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VP44 Diagnostic for everyone.

140K views 27 replies 15 participants last post by  Brettt 
#1 · (Edited)
This information I am pasting down here is not mine. I got this from VP44 Diagnostic www.BlueChipDiesel.com

I heard they have the top of the line VP44's for a bargin! They also have very accurate overviews and diagnostics of the VP44 so you do not waste thousands! All credibility goes to BlueChipDiesel.

Overview

I feel qualified to help you as I owned a full service performance shop for all Dodge Diesels, and Freightliner and Ford trucks with the ISB engine, from 1993 through 2006, when I became a website only, to specialize in this often misunderstood fuel system. Way back in 1998 when my brother and I received the only US Patent for enhancing fuel delivery for electronically controlled diesel engines, I felt that the research we did then might have made us a bit smarter than most, but I have to admit that the experience I have gained SINCE then has made me a much better teacher. As I still answer the phone every chance I get, I am still learning from all of you, to give me way more REAL WORLD EXPERIENCE than others in the industry. This is why I feel BEST qualified to help you. I am happy to share this knowledge and experience to help you make an accurate diagnosis of your truck’s VP44 fuel system and direct you to purchase the right part the first time. As I learn more I rewrite this amazing document to make it even better, so keep checking the update date so you are assured of the latest and greatest information.

My REAL WORLD experience has allowed me to really fine tune what works and doesn’t work for diagnosing this fuel system. To diagnose this fuel system requires a unique approach and a sense of humor as you can’t just plug in scan tool to get all the RIGHT answers. You likely can’t get what you need from a shop manual either as that was probably written before I acquired all the knowledge and diagnostic experience I have now. The codes that are in the ECM are a help, but in some cases mean nothing unless accompanied by a certain symptom. You only need to read the codes in the ECM as that is the only computer that runs the fuel system. The PCM is for all other systems in the truck. In SOME cases the codes we DON’T get are the most important part of determining an accurate diagnosis. If you follow these diagnostic procedures below you WILL get accurate answers, but not necessarily the answers you like! I am so confident in what I am about to share with you, that I make this promise. If you buy an injection pump from me that I have diagnosed with you over the phone, and it doesn’t fix your problem, I’ll take it back within the first week!

There are six components in the fuel system in a VP44 fueled truck. They are the ECM (Engine Control Module), Fuel Injectors, APPS (Accelerator Pedal Position Sensor), MAP Sensor (also known as a Boost Sensor), Fuel Filter, Lift Pump and finally the VP44 Injection pump. The ECM and OEM Injectors almost never give any problem in my experience. In fact up until 2009 I had never even heard of a bad ECM, even at crazy high mileages, so they didn’t need further consideration. Now that these trucks are getting older, I have to eat these words.The APPS and MAP Sensor rarely are a problem, and can be diagnosed with the info below. The Fuel Filter and the Lift Pump have their own diagnostic page that can be accessed by clicking on the link at the bottom of this page. This leaves the VP44 Injection Pump, which is almost always the cause of drivability issues and symptoms.

PERTINENT CODES

In my experience the 216 code is not a “Death Code” as some people say. It only tells you the injection pump can’t attain full timing advance and therefore power, and if this code is the ONLY code and you don’t have any other symptoms, the VP44 does not need to be replaced, and will not put you on the side of the road. If you DO have the 216 code you should check your lift pump pressure UNDER LOAD as lift pump pressure is what moves the timing piston and advances timing, so if lift pump pressure is low, that may be the cause of the 216 code. If lift pump pressure is good, then the code means the housing of the injection pump is worn out, which in itself still isn’t a reason to replace the VP44 either, in my mind. Click on the icon on the bottom of the last page of this section for how to diagnose a lift pump accurately.

If the truck won’t start, AND YOU HAVEN’T OPENED ANY FUEL LINES OR REPLACED THE FUEL FILTER SINCE IT LAST RAN, and you have either or both a 1688 and or a 1689 DTC code, the truck will never start until you replace the injection pump, 99% of the time. If you want to be 100% sure of your diagnosis, follow the “No Start” diagnosis below. These codes indicate either a serious internal mechanical failure, such as a seized rotor, or that the computer on the top of the injection pump is not turning on the high pressure fuel to the injectors. Other circumstances like stray RF (radio interference) can cause false codes and therefore confuse or misdirect an accurate diagnosis, so this is where symptoms have more merit than just codes, when diagnosing this fuel system. Code 1693 only means there is at least one code in the other computer, which is the PCM, which has NOTHING to do with the fuel system related drivability problems. Sometimes automatic transmission issues cause a drivability issue and appear to be a fuel system issue. In this case codes in the ECM and the PCM should be duly noted and COMBINED with the drivability SYMPTOMS and a phone call to me, I can differentiate and diagnose the problem with you.To come up with an accurate diagnosis sometimes, you have to prove all the other components of the fuel system that could cause your unique problem, are indeed good. If you have done that, you have no choice but to condemn the injection pump. This is where a missing code along with a drivability issue, is more important than an existing one!

WHY YOU SHOULD CHECK FUEL SUPPLY FIRST

You may think that low fuel supply pressure will cause many or all drivability problems, but NOT SO with this fuel system. Human nature also makes us want to take the path of least resistance, or lowest out of pocket expense, and try replacing the less expensive components before diagnosing this fuel system correctly. Please know that Lift Pumps have their own problems, but are RARELY the cause of an injection pump failure, or a drivability complaint, contrary to what a lot of people want you to believe.

A weak or failed lift pump or a plugged fuel filter will NOT give any other drivability issues OTHER than a skip, miss or buck at high load/high RPM operation. If you DO experience ONLY these symptoms, replace the fuel filter and if you can’t bleed the system, or if changing the filter doesn’t fix the problem, go to “How to Diagnose a Lift Pump” at the bottom of this page and proceed from there.

You MAY have to do a lift pump diagnosis or replace the fuel filter after you put on a new injection pump because the new injection pump may make more power than the old one, therefore using more fuel, and therefore lowering the fuel delivery pressure to the point that you then have the skip or miss at high rpm/load symptoms. Be sure that you have at least 5 PSI Lift Pump pressure UNDER LOAD at all times, to be sure low lift pump pressure isn’t preventing full power or timing advance, and or causing any harm to the old style diaphragm in the VP44. We strongly suggest installing our “Low Fuel Pressure Warning Kit” to monitor fuel pressure, as a diagnostic tool and a future money saving tool. It will tell you when the restriction in the filter necessitates replacing the filter, which means you will change your filter by restriction rather than the seat of your pants and save replacement filter costs! It will also tell you if the lift pump fails mechanically or electrically. Go to our “Product List” for more info about this inexpensive money saving product.

READING CODES

If you have a late model year 2000 – 2002 truck you can read the codes by turning the ignition switch to the “run” position from the “off” position 3 times within 5 seconds and leave it in the “run” position and stare at the odometer. Write down the information displayed, so you don’t forget it when you call me, and it will help your diagnosis. To be sure the codes are pertinent to the current issue, I recommend that you clear the codes after you first read them, with a good scan tool, such as a DRB III. Then REREAD THE CODES BEFORE YOU START THE ENGINE to be sure they are actually cleared, as some scan tools don’t clear all the codes. Then drive the truck until the problem reappears, and then reread the codes. If there is no new code, that is very valuable information, and if you do have a newly set code, it is most likely relevant to your symptom. You can tell what computer you are reading by the code(s) you get. If it pertains to the engine or fueling, then it is the ECM and if it pertains to the rest of the truck it is the PCM. If you get a 1693 code that only tells you there is a code or codes in the other computer. If you have a 1998-99 or a grumpy 2000, reading codes this way will not work, so you’ll have to read the codes with a scan tool. Most auto parts stores will do this for free for you.

DEAD PEDAL

This is THE MOST COMMON DRIVABILITY COMPLAINT and is an intermittent one that happens most often when the truck is hot or working harder, but can occur much less frequently when cold too. My experience tells me that 4 times out of 5 “Dead Pedal” is worse hot, but 1 time in 5 it is worse cold! There are no codes pertaining to “Dead Pedal” that will condemn the computer and therefore the VP44.

This is due to “Lead Free” solder failure, now mandated by the federal Government!

The symptom of “Dead Pedal” is rarely caused by a faulty APPS (Accelerator Pedal Position Sensor) and 90% of the time it is caused by a faulty computer on the top of VP44 injection pump. These numbers are NOT an exaggeration. The easiest way to positively eliminate or condemn the APPS as the cause of the problem is to “scan" or read the ECM (not the PCM) in your truck to check for any codes pertaining to the APPS, such as a 121 or 122. If you DO have either or both of these codes you MAY need an APPS. IF YOU DON’T HAVE EITHER OR BOTH OF THESE CODES, THEN YOU PROBABLY DON’T NEED AN APPS, but to be sure, do this definitive test. Diagnosing an APPS accurately can be done with an ANALOG voltmeter, by monitoring and measuring the signal voltage on the blue wire with a black tracer (on Dodges) coming from the APPS electrical plug. Turn the ignition key to the “on” position and slowly press on the throttle and slowly release it. You should not ever see a jump in voltage. It should go up and down smoothly. If it repeatedly jumps up or down, then replace the APPS. As this sensor can be very intermittent, I strongly suggest you do the following test when driving the truck to prove the APPS is or isn’t the cause of your dead pedal. Extend the signal wire used in the previous test up to the dash of the truck and drive it while watching the voltage on your voltmeter. If you are holding the pedal still and the voltage drops when the engine drops power, you need an APPS. If the voltage stays the same and the power drops, you need an injection pump!

IF YOU DON’T NEED AN APPS, AND YOU HAVE DEAD PEDAL SYMPTOMS, YOU FOR SURE NEED A VP44!

If you don’t have access to a scan tool or an analog voltmeter, and want to trust my experience, let me explain the difference in symptoms between a bad APPS and a bad computer on the injection pump. A bad APPS usually is just a flat spot at a certain throttle opening, usually 65-70 MPH, and smacking the pedal to the floor a few times, usually clears it up. If pushing the throttle just a bit more makes it take right off, or if going back to a lesser throttle opening makes the engine run fine, then it is most likely a bad APPS. This usually occurs most frequently, but not always, in cold and or wet conditions. If it is caused by the computer on the VP44, the “Dead Pedal” or power drop occurs at ALL throttle positions and power comes back only if you let the pedal go to idle for a brief time to reestablish “Idle Validation”, or push the clutch in, or shut off and restart the engine, or just wait. This kind of "Dead Pedal" happens most often hot or towing, but sometimes when cold.

TRUCK DIES GOING DOWN THE ROAD

Another VP44 failure is when the truck dies driving down the road for no apparent reason, or when you let off the throttle at high RPM, and the engine won’t restart. This is usually a seized rotor in the injection pump and is most common on 1998 and 1999 trucks, or rebuilt pumps that don’t have the upgraded rotor and distributor. The cause of this failure is a poorly "deburred" rotor, according to Bosch. This machining problem has been addressed and apparently solved in later years, with the updated parts we use. If you run any rotary style pump like a VP44 out of fuel at high RPM you CAN seize the rotor because it runs out of lubrication! This symptom can also be due to contaminated fuel and related corrosion on internal parts of the pump, or an electrical failure of the computer on top of the VP44.
IMPORTANT FACT:
TO MAKE THE ENGINE START AND IDLE ONLY, YOU DON’T NEED ANY SENSORS OR COMPUTERS OR ELECTRIC LIFT PUMP. YOU ONLY NEED 12 VOLT POWER, GROUND, AND FUEL TO THE VP44.

NO START – TEST #1 FUEL SUPPLY TEST

If the fuel gauge reads 1/8 – 1/4 of a tank, put a few gallons in the tank and bleed the fuel system. I say this because of the famous Dodge fuel tank sender problem. Your gauge may be out of calibration for the first time and the tank is actually empty. In this situation air AND fuel is what you are trying to start the engine with! Pressure indicators don’t know the difference between air and fuel pressure, so you may falsely think all is OK. You will be very glad you did this if your truck runs again and you don’t need an injection pump!

If the engine WAS running BEFORE you CHANGED THE FUEL FILTER OR OPENED A FUEL LINE, AND IT HASN’T STARTED SINCE, or, it started and stalled after doing this, AND IT WON’T BLEED and restart, and you can hear the lift pump running, but it won’t fill the filter bowl, you most likely have a bad electric lift pump. Please remember when you are doing this diagnosis that the ECM turns on the electrical power to the electric lift pump only for 4 seconds when the key is in the “on” or “run” position. When the ECM sees the “start” signal from the ignition switch it runs the pump for 25 seconds, and when it sees idle RPM it runs continuously. If the electric lift pump doesn’t come on, or doesn’t pump fuel into the filter bowl when you click the key to the “start” and release it to the “run” position, you can bleed the system to get fuel to the VP44 and get the engine to run again, by pressurizing the fuel tank with air pressure, or diagnosing the electric lift pump. The reason this strange scenario happens, is because there is a mechanical lift pump built into the VP44 which works fine UNTIL air gets into the system. This explains why VP44 fueled engines don’t die on the side of the road when the electric lift pump fails.

NO START – TEST #2 ELECTRICAL TEST

The next no start test procedure is to test the electrical wiring and verify that there is battery voltage getting to the VP44 with the key in the “run” AND ”start” position. Remove the big plug on the back of the injection pump by wiggling the plug with your right hand pulling toward the firewall and the left hand pulling the indented locking tab toward the fender. When you have the plug in your hand, hold it so it looks like a smiley face, with six pins below the smile and three pins above. Using a test light or voltmeter, verify battery voltage on the bottom right pin (pin #7, which is a red wire with a light green tracer) during both “run” and “start” key functions and verify the ground on the bottom left pin (pin#6, which is a black wire with a tan tracer) by doing a voltage test at the positive battery terminal with the ground lead of the test light or voltmeter on pin 6. Use only pin positions, not wire color, if diagnosing a Ford or Freightliner. If you don’t have power at the plug, research the voltage supply to it. Is the fuse in the PDC (Power Distribution Center, aka fuse box under the hood) for the fuel system OK? If it is, then swap the fuel system relay with the one for the horn. If you have battery voltage on pin #7 in both key positions, and a known good ground on pin 6, cut the black tape off the VP44 plug harness to access the wires going into the plug and reinstall plug. On Dodges find the light blue wire with a red tracer (pin #5) and verify that there is NOT battery voltage there during either the “run” or the “start” functions of the ignition switch, WITH THE PLUG PLUGGED IN. The ONLY time there should be battery voltage on pin 5, is for about three seconds after turning the key to the “off” position. If there is battery voltage there at any other time, the engine is being told to not start or run by a pissed off ECM. This test is accurate 99% of the time in my experience. It is not unusual and OK to see low voltage, like .2 -.4 volts at pin 5. The important thing here is to NOT have battery voltage here, and if you do have it there at the wrong times, I have found cutting that wire and running the truck forever that way causes no harm!

NO START TEST #3 HOT WIRE TEST - THE BEST TEST

If you want to be 100% sure it is the pump causing the no start , and not a pissed off ECM or “BUSS” wiring issue to the VP44, follow these next directions exactly, to be sure of not damaging a possibly good pump. This test POSITIVELY eliminates the possibility of overlooking an electrical problem that could affect the start or run function of the VP44, as long as you have verified fuel delivery to the injection pump. Remove the electrical plug at the back of the injection pump and hot wire the pins on the pump as follows. Get two wires long enough to reach from the battery to the VP44. Install an INSULATED ¼ inch female spade connector onto one end of each wire. Connect one INSULATED connector to pin 7 on the pump, which is the pin on the BOTTOM row of the socket on the injection pump, closest to the engine, to preferably fused (10 amp is fine) positive battery power in the PDC (Fuse box under the hood), or directly to the positive battery terminal if you like to take risks!.

Connect the other INSULATED connector to the pin directly above the previous connection, the top row of pins, the one closest to the engine, and attach the other end to battery ground. Now try to start the engine and if it doesn’t start, you absolutely positively 100% need an injection pump! If the engine starts this way but not with the big plug installed on the pump, you know there is something in the 12 volt wiring or buss wiring to the ECM causing the engine to not start. Call me for help if this is the case.

IF YOU HAVE FUEL, POWER AND GROUND, PROVEN BY THE ABOVE TESTS AND STILL HAVE NO START, YOU NEED AN INJECTION PUMP!

If you still want more proof that you need an injection pump after you have proven that you do indeed have electrical power, ground, and fuel to the injection pump, loosen three injector lines at the valve cover. Crank the engine a few times for 30 seconds each time, and if high pressure fuel only comes out of one line or none of the lines, this indicates either a seized rotor, or a stuck fuel solenoid pintle valve. To start the engine you need high pressure FUEL delivery, AND NOT AIR, to at least three of the injectors, NOT just lift pump pressure. To determine if it is or is not HIGH pressure, look for a puddle on the ground after 60 seconds of cranking. No puddle, no high pressure. We proved that you cannot put this pump in a hydraulic lock as the rotor turns, so therefore fuel, low or high pressure, HAS to come out of one injection line even if the rotor is not turning. If high pressure fuel doesn’t come out of any of the open lines, the rotor may be stuck or seized at a closed line. If the rotor IS turning, therefore not seized, and the solenoid pintle valve is stuck in the open position, or the pistons are stuck compressed in the rotor, due to fuel contamination or corrosion, you won’t get high pressure fuel out of any line and the engine will NOT run. If you don’t have high enough pressure to pop off the injectors the engine can’t start. If you have only a feeble fuel flow, this is due to having only lift pump pressure moving fuel through the lines. This injection pump failure is either caused by an electrical issue in the computer or a mechanical issue, neither of which you can fix. Either of these situations confirms that the engine will not start until you replace the VP44, as long as you have done the other tests above.
 
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#2 · (Edited)
HARD START HOT, LONG CRANK TIMES, and then instantly runs smoothly

Hard start hot is ALWAYS an electrical issue due to heat soak, where the computer gets hot from the latent heat from the engine after the engine is shut off. Cooling the computer by either time or an outside source restores the crystallized and therefore intermittent lead free solder connection(s) on the computer circuit board, and it takes off and starts. To test for this or convince yourself that I am right, try this trick. Run cold water over the computer on the top of the injection pump for a few minutes the next time you know it will be hard to start, and if it starts right up you know you need a new pump.

HARD START COLD, LONG CRANK TIMES, and then instantly runs smoothly

This is most often due to a cracked or broken diaphragm inside the injection pump. To test for this try disconnecting the electrical power from the lift pump BEFORE turning the key on, and see if it starts better. This can happen because the electric lift pump pushes air from the fuel chamber inside the VP44 pump, through the crack or break in the diaphragm, into the mechanical high pressure pump and it becomes air-bound until the mechanical pump rotates enough times to bleed out the air. If it starts better without an electric lift pump, that indicates leak down in the high pressure mechanical pump due to a cracked or broken diaphragm which means VP44 replacement to fix the problem.
HARD START, COLD OR HOT, LONG CRANK TIMES, runs rough for a few seconds after start and then clears up and runs smoothly, or ENGINE SOUNDS DIFFERENT OR LOUDER UNDER LOAD, OR MAKES A CRACKLING SORT OF SOUND

AIR IN FUEL TEST

If the engine runs rough for a brief period of time after starting, just a few seconds, or sounds funny when running, this usually indicates air in the fuel supply system, caused by either fuel drain back or air getting into the fuel supply line somewhere. This symptom is NOT caused by the injection pump. Please know that good fuel pressure does NOT mean that there is no air in the supply line, as the pressure sensor doesn’t know the difference between fuel and or air pressure! My latest trick to accurately determine if air is a problem is to get a 12 foot section of clear polyethylene or vinyl 3/8” hose from the hardware store and put it in the steel line between the fuel filter and the injection pump where the rubber section is. For aftermarket plumbing upgrades, figure out how to install it between the fuel filter and the injection pump. Loop it up under the windshield wiper for easy observation while driving and starting. Bleed the system to get all the air out of the newly installed line, and when you know the engine will be hard to start, monitor the line before, during, and after starting, and even driving, to determine if air ever gets into the pump. This test positively tells you that you DO or DO NOT have an air issue which can be very important when diagnosing the VP44 fuel system. If you do have air in the clear line, run the engine from a can of diesel in the bed of the truck with a rubber hose stuck in it, connected to the inlet of the lift pump. If the air goes away, the problem is behind the lift pump. If it is still there, it is forward of the inlet of the lift pump. This can be the lift pump itself, if it is a Fass with a leaky o-ring inside, leaking sealing washers, or it can be the o-rings on the “Fuel Tubes” in the cylinder head. Call me if you need more help determining where the air is coming from.

ROUGH OR ROLLING IDLE OR INTERMITTENT MISS AT HIGHWAY SPEEDS AT LESS THAN FULL THROTTLE

This is almost always the computer on the top of the injection pump, especially if it only happens warm or hot, as long as there is no air in the fuel and no relevant codes. If those codes exist, diagnose and or replace those components. It can also be an internal mechanical issue. This only means REPLACE THE VP44!

TRUCK IS DOGGY ON TAKEOFF, COLD

If the truck is gutless when driving for the first little while after start up cold, and then all of a sudden takes off and runs fine, this is always a bad computer on top of the injection pump, IF THERE ARE NO CODES TO INDICATE ANY OTHER COMPONENT, which of course means replace the injection pump. If you can predict when it is going to do this, try heating the computer on top of the pump with a hair dryer for a few minutes when you know it will be bad, and if the heat fixes it immediately, you know I am right.

DOGGY ON TAKE OFF, COLD OR HOT, AND NOT DEAD PEDAL

This one is rare AND tricky to accurately diagnose. The ECM needs to see voltage above and below certain parameters to NOT cutback or restrict fuel delivery from the VP44. The ECM wants to only see MAP signal voltage on 1998 through 2000 trucks between .5 and 1.74 volts and 1.0 to 2.2 volts on 2001-2002 trucks. If the signal voltage is outside of these parameters, the ECM will cut back fuel delivery commands to the VP44 and make the engine run in a de-rated or “Limp” mode. If this symptom is the ONLY drivability complaint and the following tests are done and the voltages are timely and right, then YOU NEED AN INJECTION PUMP! If this symptom isn’t the only drivability issue, then you probably have condemned the VP44 pump already, from another test. Either with a scan tool, or voltmeter on the signal wire of the MAP sensor, which is grey with a red tracer in a Dodge, verify that the MAP signal voltage is at .5 volt for 98, 99 and 2000 trucks at idle and or “key on” and 1.0 volt on 01 and 02 trucks. If the signal voltage is lower than these specs during this test, it can be due to a bad sensor, but more likely because the truck has a device on it that attaches to the MAP sensor, like a timing box or electronic gauge setup, that draws the voltage down below the desired parameters. To determine which component is possibly the cause, disconnect the wires of the device(s) from the MAP sensor harness. You can’t just turn it (them) off, to see if the problem goes away, because any device hooked up to either the 5 volt supply wire or the signal wire at the MAP sensor, can draw the voltage down, even if it isn’t turned on. If the MAP signal voltage is still lower than spec after disconnecting the device(s), call me to find out how to give the MAP Sensor an enema to fix the low voltage and related delayed fueling. If the voltages are right after this test, then attach an extension wire from the signal wire up to the dashboard and read the voltage with a volt meter when the truck is driven.

Monitor the MAP signal voltage on gentle take off and if the voltage stays low and then jumps higher and then the truck takes off, you probably need a MAP Sensor. If the voltage rises almost immediately and the truck is still doggy, YOU NEED AN INJECTION PUMP! The tricky part of this diagnosis is determining if the voltage goes up exactly as fast as the fuel demand is increased, or a while afterwards, to determine where to place the blame.

RPM GOES UP ON ITS OWN OR WAIT TO START LIGHT IS DUMB

This is a new one for 2010. A few of my callers have remarked that the RPM goes up on it’s own, so we have them check that the signal voltage, on the blue wire with a black tracer signal wire (on Dodges) coming from the APPS, doesn’t go up or down when the RPM goes whacky, which confirms it is NOT the APPS. Therefore it only makes sense to blame the ECM. If you hot wire the pump as explained in “No Start” above and the idle is smooth, but if the idle rolls or is erratic with the VP44 plug being plugged in, and the APPS is good, then you have to blame the ECM. The other strange symptom or indicator of a bad ECM is when the truck won’t start until you see the “wait to start” light go out, or it comes on when driving. These are the only two symptoms that I have seen or heard of, SO FAR, that necessitate replacing or repairing the ECM. As these trucks are getting older, and only in the last few years, have I very rarely heard of these symptoms. The good news is these symptoms are unique so far! At least one of the symptoms described above have been common to all the very few ECMs that I have found to need repair or replacement. The only way to diagnose an ECM in my experience is to try a replacement. It doesn’t seem to matter what year or engine rating the test ECM comes from, with or without a crank sensor, as long as the above symptoms go away with the borrowed test unit. I have had many callers do it this way, so I feel confident you won’t hurt anything as long as you remember one thing, PLEASE. When installing any ECM, be SURE to ground it to the engine FIRST, before connecting the big plug. This prevents any problem from static electricity or a voltage spike getting into the ECM which can blow away the software and or computer inside. Yes the test ECM may set codes, but if it runs better and or doesn’t have the above symptoms any more, then you know a replacement or repaired ECM is in your future.

CONTAMINATED FUEL AND ALTERNATE FUELS

Lastly, is the internal injection pump damage caused from using WVO, more than 5% Biodiesel or contaminated fuel. The resulting corrosion inside the injection pump causes the close tolerance parts inside to seize or stick and cause drivability complaints, such as a high speed skip, low power or no start. These problems can rarely be cured by some sort of fuel additive being put in the fuel AFTER the problem is observed.

These corrosion problems are the most common reason Bosch denies a warranty claim. Contamination rusts or corrodes and therefore destroys the internal components in VP44 pumps. Most often if there are drivability issues due to contaminated fuel, ALL the internal parts of the injection pump will be ruined and have to be thrown out, which usually means the pump is not worth rebuilding, and possibly not even eligible to be a core! These situations are so hard for me to deal with and explain to customers, because typically they don’t know they have a contaminated fuel issue until too late, when we open up the pump for warranty consideration, failure diagnosis, or repair.
IN CLOSING

If you think you might need an APPS, Injection Pump, Low Fuel Pressure Warning Kit, or a Lift Pump, but aren’t sure of your diagnosis after reading all this rhetoric, give me a call and I’ll try to explain it in terms you will understand, to verify an accurate diagnosis with you. If you really do need a replacement part, I surely hope you will consider Blue Chip Diesel to supply you with an improved unit that has all the best and latest upgrades to give you the best performance and bang for your buck. Selling better replacement parts is how I pay the phone bill and support this website!

I hope you can learn in a few hours from this diagnostic sheet what has taken me many years to collect, to research and prove, works efficiently and accurately. I keep updating this as I get smarter in an effort to help my potential customers make accurate and wise decisions, and I want to thank all those people that have learned from this and then became customers. To all of you that have spoken with me over the years to get me to this place, I humbly say THANK YOU!

Any and all suggestions for this awesome document will be gladly received.

Thanks for reading, Chip Fisher

Blue Chip Diesel 888-ISB–PERF or 603-966-6459

Email info@bluechipdiesel.com

9AM TO 5PM MONDAY THROUGH FRIDAY, EASTERN TIME
 
#3 ·
If this against the rules for pasting this and or is in the wrong section please inform me. I am only trying to help since I am having the same problems as well and this has clearly summed my problem up in a matter of reading this!
 
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#5 ·
Thanks I am trying to get thanks and posts to keep it at the top! Hopefully can get stickied at the top eventually.
 
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#7 ·
I have a question about the timing of the VP. Does the VP use the cam sensor for calculating top dead center or does it do this internally? If it does it with the cam sensor, then does it get the info from the ecm and can a bad sensor or bad ecm signal for timing cause issues. I don't remember reading anything about this in your post.
 
#8 ·
A question like that should be sent directly to him at info@bluechipdiesel.com . He is the man you want to talk to. A LOT of experience under his belt with fuelling systems.
 
#9 ·
to the top
 
#10 ·
Chip is a worthless POS! I spent $2200 on his pump and 8 months later the case halves separated. He declined my warranty and ignored all my calls. I called on another phone and he hung up once he got my name.
 
#12 ·
Very well, I did not see that post at all. Feel free to remove this post If need be. Sorry guys just trying to help all!
 
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#13 ·
Friendly bump for whomever likes to read :)
 
#14 ·
Hey thanks for the post!! Looks like Im right, I need a new pump though. :banghead::banghead:
 
#15 ·
No problem at all. Yea, I was in the same position when I read this. So I dropped $1500 on vp$$ and Raptor 150. In shop now being installed waiting for it to get out so I can be 100% it was.
 
#17 ·
hey i think my truck has the doggy take off when cold symtoms. it feels like bad turbo lag through 1,2,3 and once it warms up its fine. the codes i got are p1694, p1693, p1698 those have somthing to do with the computers not comunicating.
do i have to replace the vp or just the computer (vp is tapped)
 
#21 ·
If I remember right, those are are codes I get from my rad box, has to do with can and bus connections. Don't know why I'm saying this as I don't know what to say for help haha. Do good more reading and chip's tests if any apply.
 
#18 ·
To the top for you guys whom need help!
 
#20 ·
#24 ·
I just recently was doing some maintenance and replaced my fuel filter, I also had a line that was leaking on my pickup pump on top of my tank. I also replaced my pickup pump because there was no way to patch that line. So, now my truck will only run for about 30 seconds at a time? I can turn my key on and off and get it to prime, and then it will crank again, but will shut off after approx. 30 seconds?
 
#25 ·
Ive been away guys. Sold the diesels, regretted it and now im back with a 4th gen! I havent veen on here much but if you need held, tbis is a bump.
 
#26 ·
This information I am pasting down here is not mine. I got this from VP44 Diagnostic Blue Chip Diesel

I heard they have the top of the line VP44's for a bargin! They also have very accurate overviews and diagnostics of the VP44 so you do not waste thousands! All credibility goes to BlueChipDiesel.

Overview

I feel qualified to help you as I owned a full service performance shop for all Dodge Diesels, and Freightliner and Ford trucks with the ISB engine, from 1993 through 2006, when I became a website only, to specialize in this often misunderstood fuel system. Way back in 1998 when my brother and I received the only US Patent for enhancing fuel delivery for electronically controlled diesel engines, I felt that the research we did then might have made us a bit smarter than most, but I have to admit that the experience I have gained SINCE then has made me a much better teacher. As I still answer the phone every chance I get, I am still learning from all of you, to give me way more REAL WORLD EXPERIENCE than others in the industry. This is why I feel BEST qualified to help you. I am happy to share this knowledge and experience to help you make an accurate diagnosis of your truck’s VP44 fuel system and direct you to purchase the right part the first time. As I learn more I rewrite this amazing document to make it even better, so keep checking the update date so you are assured of the latest and greatest information.

My REAL WORLD experience has allowed me to really fine tune what works and doesn’t work for diagnosing this fuel system. To diagnose this fuel system requires a unique approach and a sense of humor as you can’t just plug in scan tool to get all the RIGHT answers. You likely can’t get what you need from a shop manual either as that was probably written before I acquired all the knowledge and diagnostic experience I have now. The codes that are in the ECM are a help, but in some cases mean nothing unless accompanied by a certain symptom. You only need to read the codes in the ECM as that is the only computer that runs the fuel system. The PCM is for all other systems in the truck. In SOME cases the codes we DON’T get are the most important part of determining an accurate diagnosis. If you follow these diagnostic procedures below you WILL get accurate answers, but not necessarily the answers you like! I am so confident in what I am about to share with you, that I make this promise. If you buy an injection pump from me that I have diagnosed with you over the phone, and it doesn’t fix your problem, I’ll take it back within the first week!

There are six components in the fuel system in a VP44 fueled truck. They are the ECM (Engine Control Module), Fuel Injectors, APPS (Accelerator Pedal Position Sensor), MAP Sensor (also known as a Boost Sensor), Fuel Filter, Lift Pump and finally the VP44 Injection pump. The ECM and OEM Injectors almost never give any problem in my experience. In fact up until 2009 I had never even heard of a bad ECM, even at crazy high mileages, so they didn’t need further consideration. Now that these trucks are getting older, I have to eat these words.The APPS and MAP Sensor rarely are a problem, and can be diagnosed with the info below. The Fuel Filter and the Lift Pump have their own diagnostic page that can be accessed by clicking on the link at the bottom of this page. This leaves the VP44 Injection Pump, which is almost always the cause of drivability issues and symptoms.

PERTINENT CODES

In my experience the 216 code is not a “Death Code” as some people say. It only tells you the injection pump can’t attain full timing advance and therefore power, and if this code is the ONLY code and you don’t have any other symptoms, the VP44 does not need to be replaced, and will not put you on the side of the road. If you DO have the 216 code you should check your lift pump pressure UNDER LOAD as lift pump pressure is what moves the timing piston and advances timing, so if lift pump pressure is low, that may be the cause of the 216 code. If lift pump pressure is good, then the code means the housing of the injection pump is worn out, which in itself still isn’t a reason to replace the VP44 either, in my mind. Click on the icon on the bottom of the last page of this section for how to diagnose a lift pump accurately.

If the truck won’t start, AND YOU HAVEN’T OPENED ANY FUEL LINES OR REPLACED THE FUEL FILTER SINCE IT LAST RAN, and you have either or both a 1688 and or a 1689 DTC code, the truck will never start until you replace the injection pump, 99% of the time. If you want to be 100% sure of your diagnosis, follow the “No Start” diagnosis below. These codes indicate either a serious internal mechanical failure, such as a seized rotor, or that the computer on the top of the injection pump is not turning on the high pressure fuel to the injectors. Other circumstances like stray RF (radio interference) can cause false codes and therefore confuse or misdirect an accurate diagnosis, so this is where symptoms have more merit than just codes, when diagnosing this fuel system. Code 1693 only means there is at least one code in the other computer, which is the PCM, which has NOTHING to do with the fuel system related drivability problems. Sometimes automatic transmission issues cause a drivability issue and appear to be a fuel system issue. In this case codes in the ECM and the PCM should be duly noted and COMBINED with the drivability SYMPTOMS and a phone call to me, I can differentiate and diagnose the problem with you.To come up with an accurate diagnosis sometimes, you have to prove all the other components of the fuel system that could cause your unique problem, are indeed good. If you have done that, you have no choice but to condemn the injection pump. This is where a missing code along with a drivability issue, is more important than an existing one!

WHY YOU SHOULD CHECK FUEL SUPPLY FIRST

You may think that low fuel supply pressure will cause many or all drivability problems, but NOT SO with this fuel system. Human nature also makes us want to take the path of least resistance, or lowest out of pocket expense, and try replacing the less expensive components before diagnosing this fuel system correctly. Please know that Lift Pumps have their own problems, but are RARELY the cause of an injection pump failure, or a drivability complaint, contrary to what a lot of people want you to believe.

A weak or failed lift pump or a plugged fuel filter will NOT give any other drivability issues OTHER than a skip, miss or buck at high load/high RPM operation. If you DO experience ONLY these symptoms, replace the fuel filter and if you can’t bleed the system, or if changing the filter doesn’t fix the problem, go to “How to Diagnose a Lift Pump” at the bottom of this page and proceed from there.

You MAY have to do a lift pump diagnosis or replace the fuel filter after you put on a new injection pump because the new injection pump may make more power than the old one, therefore using more fuel, and therefore lowering the fuel delivery pressure to the point that you then have the skip or miss at high rpm/load symptoms. Be sure that you have at least 5 PSI Lift Pump pressure UNDER LOAD at all times, to be sure low lift pump pressure isn’t preventing full power or timing advance, and or causing any harm to the old style diaphragm in the VP44. We strongly suggest installing our “Low Fuel Pressure Warning Kit” to monitor fuel pressure, as a diagnostic tool and a future money saving tool. It will tell you when the restriction in the filter necessitates replacing the filter, which means you will change your filter by restriction rather than the seat of your pants and save replacement filter costs! It will also tell you if the lift pump fails mechanically or electrically. Go to our “Product List” for more info about this inexpensive money saving product.

READING CODES

If you have a late model year 2000 – 2002 truck you can read the codes by turning the ignition switch to the “run” position from the “off” position 3 times within 5 seconds and leave it in the “run” position and stare at the odometer. Write down the information displayed, so you don’t forget it when you call me, and it will help your diagnosis. To be sure the codes are pertinent to the current issue, I recommend that you clear the codes after you first read them, with a good scan tool, such as a DRB III. Then REREAD THE CODES BEFORE YOU START THE ENGINE to be sure they are actually cleared, as some scan tools don’t clear all the codes. Then drive the truck until the problem reappears, and then reread the codes. If there is no new code, that is very valuable information, and if you do have a newly set code, it is most likely relevant to your symptom. You can tell what computer you are reading by the code(s) you get. If it pertains to the engine or fueling, then it is the ECM and if it pertains to the rest of the truck it is the PCM. If you get a 1693 code that only tells you there is a code or codes in the other computer. If you have a 1998-99 or a grumpy 2000, reading codes this way will not work, so you’ll have to read the codes with a scan tool. Most auto parts stores will do this for free for you.

DEAD PEDAL

This is THE MOST COMMON DRIVABILITY COMPLAINT and is an intermittent one that happens most often when the truck is hot or working harder, but can occur much less frequently when cold too. My experience tells me that 4 times out of 5 “Dead Pedal” is worse hot, but 1 time in 5 it is worse cold! There are no codes pertaining to “Dead Pedal” that will condemn the computer and therefore the VP44.

This is due to “Lead Free” solder failure, now mandated by the federal Government!

The symptom of “Dead Pedal” is rarely caused by a faulty APPS (Accelerator Pedal Position Sensor) and 90% of the time it is caused by a faulty computer on the top of VP44 injection pump. These numbers are NOT an exaggeration. The easiest way to positively eliminate or condemn the APPS as the cause of the problem is to “scan" or read the ECM (not the PCM) in your truck to check for any codes pertaining to the APPS, such as a 121 or 122. If you DO have either or both of these codes you MAY need an APPS. IF YOU DON’T HAVE EITHER OR BOTH OF THESE CODES, THEN YOU PROBABLY DON’T NEED AN APPS, but to be sure, do this definitive test. Diagnosing an APPS accurately can be done with an ANALOG voltmeter, by monitoring and measuring the signal voltage on the blue wire with a black tracer (on Dodges) coming from the APPS electrical plug. Turn the ignition key to the “on” position and slowly press on the throttle and slowly release it. You should not ever see a jump in voltage. It should go up and down smoothly. If it repeatedly jumps up or down, then replace the APPS. As this sensor can be very intermittent, I strongly suggest you do the following test when driving the truck to prove the APPS is or isn’t the cause of your dead pedal. Extend the signal wire used in the previous test up to the dash of the truck and drive it while watching the voltage on your voltmeter. If you are holding the pedal still and the voltage drops when the engine drops power, you need an APPS. If the voltage stays the same and the power drops, you need an injection pump!

IF YOU DON’T NEED AN APPS, AND YOU HAVE DEAD PEDAL SYMPTOMS, YOU FOR SURE NEED A VP44!

If you don’t have access to a scan tool or an analog voltmeter, and want to trust my experience, let me explain the difference in symptoms between a bad APPS and a bad computer on the injection pump. A bad APPS usually is just a flat spot at a certain throttle opening, usually 65-70 MPH, and smacking the pedal to the floor a few times, usually clears it up. If pushing the throttle just a bit more makes it take right off, or if going back to a lesser throttle opening makes the engine run fine, then it is most likely a bad APPS. This usually occurs most frequently, but not always, in cold and or wet conditions. If it is caused by the computer on the VP44, the “Dead Pedal” or power drop occurs at ALL throttle positions and power comes back only if you let the pedal go to idle for a brief time to reestablish “Idle Validation”, or push the clutch in, or shut off and restart the engine, or just wait. This kind of "Dead Pedal" happens most often hot or towing, but sometimes when cold.

TRUCK DIES GOING DOWN THE ROAD

Another VP44 failure is when the truck dies driving down the road for no apparent reason, or when you let off the throttle at high RPM, and the engine won’t restart. This is usually a seized rotor in the injection pump and is most common on 1998 and 1999 trucks, or rebuilt pumps that don’t have the upgraded rotor and distributor. The cause of this failure is a poorly "deburred" rotor, according to Bosch. This machining problem has been addressed and apparently solved in later years, with the updated parts we use. If you run any rotary style pump like a VP44 out of fuel at high RPM you CAN seize the rotor because it runs out of lubrication! This symptom can also be due to contaminated fuel and related corrosion on internal parts of the pump, or an electrical failure of the computer on top of the VP44.
IMPORTANT FACT:
TO MAKE THE ENGINE START AND IDLE ONLY, YOU DON’T NEED ANY SENSORS OR COMPUTERS OR ELECTRIC LIFT PUMP. YOU ONLY NEED 12 VOLT POWER, GROUND, AND FUEL TO THE VP44.

NO START – TEST #1 FUEL SUPPLY TEST

If the fuel gauge reads 1/8 – 1/4 of a tank, put a few gallons in the tank and bleed the fuel system. I say this because of the famous Dodge fuel tank sender problem. Your gauge may be out of calibration for the first time and the tank is actually empty. In this situation air AND fuel is what you are trying to start the engine with! Pressure indicators don’t know the difference between air and fuel pressure, so you may falsely think all is OK. You will be very glad you did this if your truck runs again and you don’t need an injection pump!

If the engine WAS running BEFORE you CHANGED THE FUEL FILTER OR OPENED A FUEL LINE, AND IT HASN’T STARTED SINCE, or, it started and stalled after doing this, AND IT WON’T BLEED and restart, and you can hear the lift pump running, but it won’t fill the filter bowl, you most likely have a bad electric lift pump. Please remember when you are doing this diagnosis that the ECM turns on the electrical power to the electric lift pump only for 4 seconds when the key is in the “on” or “run” position. When the ECM sees the “start” signal from the ignition switch it runs the pump for 25 seconds, and when it sees idle RPM it runs continuously. If the electric lift pump doesn’t come on, or doesn’t pump fuel into the filter bowl when you click the key to the “start” and release it to the “run” position, you can bleed the system to get fuel to the VP44 and get the engine to run again, by pressurizing the fuel tank with air pressure, or diagnosing the electric lift pump. The reason this strange scenario happens, is because there is a mechanical lift pump built into the VP44 which works fine UNTIL air gets into the system. This explains why VP44 fueled engines don’t die on the side of the road when the electric lift pump fails.

NO START – TEST #2 ELECTRICAL TEST

The next no start test procedure is to test the electrical wiring and verify that there is battery voltage getting to the VP44 with the key in the “run” AND ”start” position. Remove the big plug on the back of the injection pump by wiggling the plug with your right hand pulling toward the firewall and the left hand pulling the indented locking tab toward the fender. When you have the plug in your hand, hold it so it looks like a smiley face, with six pins below the smile and three pins above. Using a test light or voltmeter, verify battery voltage on the bottom right pin (pin #7, which is a red wire with a light green tracer) during both “run” and “start” key functions and verify the ground on the bottom left pin (pin#6, which is a black wire with a tan tracer) by doing a voltage test at the positive battery terminal with the ground lead of the test light or voltmeter on pin 6. Use only pin positions, not wire color, if diagnosing a Ford or Freightliner. If you don’t have power at the plug, research the voltage supply to it. Is the fuse in the PDC (Power Distribution Center, aka fuse box under the hood) for the fuel system OK? If it is, then swap the fuel system relay with the one for the horn. If you have battery voltage on pin #7 in both key positions, and a known good ground on pin 6, cut the black tape off the VP44 plug harness to access the wires going into the plug and reinstall plug. On Dodges find the light blue wire with a red tracer (pin #5) and verify that there is NOT battery voltage there during either the “run” or the “start” functions of the ignition switch, WITH THE PLUG PLUGGED IN. The ONLY time there should be battery voltage on pin 5, is for about three seconds after turning the key to the “off” position. If there is battery voltage there at any other time, the engine is being told to not start or run by a pissed off ECM. This test is accurate 99% of the time in my experience. It is not unusual and OK to see low voltage, like .2 -.4 volts at pin 5. The important thing here is to NOT have battery voltage here, and if you do have it there at the wrong times, I have found cutting that wire and running the truck forever that way causes no harm!

NO START TEST #3 HOT WIRE TEST - THE BEST TEST

If you want to be 100% sure it is the pump causing the no start , and not a pissed off ECM or “BUSS” wiring issue to the VP44, follow these next directions exactly, to be sure of not damaging a possibly good pump. This test POSITIVELY eliminates the possibility of overlooking an electrical problem that could affect the start or run function of the VP44, as long as you have verified fuel delivery to the injection pump. Remove the electrical plug at the back of the injection pump and hot wire the pins on the pump as follows. Get two wires long enough to reach from the battery to the VP44. Install an INSULATED ¼ inch female spade connector onto one end of each wire. Connect one INSULATED connector to pin 7 on the pump, which is the pin on the BOTTOM row of the socket on the injection pump, closest to the engine, to preferably fused (10 amp is fine) positive battery power in the PDC (Fuse box under the hood), or directly to the positive battery terminal if you like to take risks!.

Connect the other INSULATED connector to the pin directly above the previous connection, the top row of pins, the one closest to the engine, and attach the other end to battery ground. Now try to start the engine and if it doesn’t start, you absolutely positively 100% need an injection pump! If the engine starts this way but not with the big plug installed on the pump, you know there is something in the 12 volt wiring or buss wiring to the ECM causing the engine to not start. Call me for help if this is the case.

IF YOU HAVE FUEL, POWER AND GROUND, PROVEN BY THE ABOVE TESTS AND STILL HAVE NO START, YOU NEED AN INJECTION PUMP!

If you still want more proof that you need an injection pump after you have proven that you do indeed have electrical power, ground, and fuel to the injection pump, loosen three injector lines at the valve cover. Crank the engine a few times for 30 seconds each time, and if high pressure fuel only comes out of one line or none of the lines, this indicates either a seized rotor, or a stuck fuel solenoid pintle valve. To start the engine you need high pressure FUEL delivery, AND NOT AIR, to at least three of the injectors, NOT just lift pump pressure. To determine if it is or is not HIGH pressure, look for a puddle on the ground after 60 seconds of cranking. No puddle, no high pressure. We proved that you cannot put this pump in a hydraulic lock as the rotor turns, so therefore fuel, low or high pressure, HAS to come out of one injection line even if the rotor is not turning. If high pressure fuel doesn’t come out of any of the open lines, the rotor may be stuck or seized at a closed line. If the rotor IS turning, therefore not seized, and the solenoid pintle valve is stuck in the open position, or the pistons are stuck compressed in the rotor, due to fuel contamination or corrosion, you won’t get high pressure fuel out of any line and the engine will NOT run. If you don’t have high enough pressure to pop off the injectors the engine can’t start. If you have only a feeble fuel flow, this is due to having only lift pump pressure moving fuel through the lines. This injection pump failure is either caused by an electrical issue in the computer or a mechanical issue, neither of which you can fix. Either of these situations confirms that the engine will not start until you replace the VP44, as long as you have done the other tests above.
Can i get a phone number to reach you?
 
#27 ·
I have a 1999 Ford mid size truck, with a dead pedal. The ECU was replaced because it was footprinted and could not be read. Then the lift pump was changed as is was not coming on at all and then finally the VP44 was changed. Now the truck starts good but will only idle. All of the previous codes are gone. Now we have code 2559. The APP was also wired up wrong we believe. Long story short we cannot get anything out of the engine except an idle. Can you help with this??
 
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