Dodge Cummins Diesel Forum banner
1 - 20 of 20 Posts

· Registered
Joined
·
160 Posts
Discussion Starter · #1 ·
So ive been trouble shooting for a bad injector this whole time... but i dont know anymore... I had it hooked up to a computer and shut off each injector one at a time... i have rain caps so it was easy to hear a difference in the exhaust... trying to find which injector is bad... well the first 5 injectors when cut off dropped to the same pitch... number 6 REALLY dropped... now dodge replaced one injector when i got it from the dealer... So this didnt make any sence to me really... THEN we were checking out the fuel pressure... at WOT at redline i was only getting 16,000psi "ish" when the book said i should be getting 23,***... Now whats weird is the computer tells you what its suppose to be as you push the throttle and the fuel pressure is right where the computer says its suppose to be... but the computer thinks im suppose to have 16,000ish at WOT when the book says different??? i forget what its called... like "set" psi or something is what the computer says... So now i have no freakin clue what could be wrong... i dont have the puff of smoke at start in the morning like a bad injector... and i have the relief valve blocked so 16000 psi is all i got? could it be a FCA (fuel pressure regulator basically)??? I did the DIY CP3 Mod but i couldnt tell you if thats when my problems started... i forget... then i read about a overflow valve? do CP3's have a overflow valve on them? something about a ball and spring? really couldnt find much on that... but i think i see it plain as day in there... any ideas guys??? Thanks for the time in advance!!
 

· Northern CA Chapter President
Joined
·
3,301 Posts
commanded rail pressure :thumbsup:

i bet it had something to do with the DIY mod you did. no offense. try replacing the fca.
 

· GA CUMMINS CREW PREZ & Captain of the USS FAILBOAT
Joined
·
5,525 Posts
so your positive its not the pressure relief valve on the rail? and double check the fca, if you got the cuts wrong, thats your problem.. and yes it does, its called a cascade overflow valve...

CASCADE OVERFLOW VALVE

DESCRIPTION
The COV is located on the front cover of the high pressure pump.
The Cascade Overflow Valve has three functions:
- regulation of lubrication fuel to the internal moving parts of the high-pressure pump
- regulation of the fuel pressure being supplied to the Fuel Control Actuator solenoid valve
- return excess fuel to the fuel tank
This regulated internal pressure is known as housing pressure, and is determined by engine displacement and power requirements
 

· Registered
Joined
·
160 Posts
Discussion Starter · #4 ·
so your positive its not the pressure relief valve on the rail? and double check the fca, if you got the cuts wrong, thats your problem.. and yes it does, its called a cascade overflow valve...

CASCADE OVERFLOW VALVE

DESCRIPTION
The COV is located on the front cover of the high pressure pump.
The Cascade Overflow Valve has three functions:
- regulation of lubrication fuel to the internal moving parts of the high-pressure pump
- regulation of the fuel pressure being supplied to the Fuel Control Actuator solenoid valve
- return excess fuel to the fuel tank
This regulated internal pressure is known as housing pressure, and is determined by engine displacement and power requirements
Im POSITIVE its not the relief valve... ive got a bolt ran through the line and into the valve blocking it off... im taking it back out after i figure this out... i dont have a rail gauge so im just using it to troubleshoot for now... i heard if you take off the FCA and flip it back and forth the piston should slide inside... if not its bad... after i first did the mod it was sticking and after giving alot of pedal the truck would cut off... but start back... so i took it off and sure enough it was stuck... took it back apart and sanded it down some more... then slid around in there fine... ill take it off again tomorrow and check if it moves... but the cuts really werent that hard so i dont think there wrong... i still left the tips and everything... is it possible the COV could be bad? its a cheaper part... is there any way to clean it or something? thanks for the time man!
 

· GA CUMMINS CREW PREZ & Captain of the USS FAILBOAT
Joined
·
5,525 Posts
not real sure about checking it, this is the operation if it tells you maybe what you could do to check it...


OPERATION
The COV has a spring-loaded center spool-piece that has a drilled channel with three passages: one for initial low-pressure lubrication, one for lubrication at housing-pressure , and one for overflow. The valve is operated in three stages based on the level of pressure at the inlet.

Stage 1
When the fuel pressure entering the tip of the COV is between 0 and 3 bar (43psi), pressure is too low to overcome regulator spring tension and fuel flows through the center channel, only . This passage always allows fuel flow through to the pump center-ring and lubricates the pump bushings and internal moving parts. This circuit also allows air to bleed during initial cranking and returns the air to the fuel tank.
The COV is in Stage 1 during cranking, only.

Stage 2
When the fuel entering the COV exceeds 5bar (80psi), but is less than 12.4bar (180psi), the spool-piece moves against spring tension aligning a second passage for lubrication purposes.
Stage 2 can be reached during cranking and initial start up.


Stage 3
When fuel pressure exceeds 12.4bar (180psi), the spool-piece aligns with the overflow passage. This stage relieves the pressure into an overflow circuit that sends the fuel back to the inlet side of the gearotor pump, thus limiting maximum fuel pressure to 12.4bar (180psi).
Lubrication fuel continues to flow through all channeled passages during this stage.
Excess fuel is sent back to the fuel tank through the fuel-return circuit
Stage 3 is reached at over-pressure
 

· Registered
Joined
·
160 Posts
Discussion Starter · #6 ·
hhmm... i guess ill just have to pull it and play with it... lol... the thing you posted says its on the front cover? like up where the belts are? i looked earlier and it looks like its right on top of the CP3... like plain as day if i look down at the CP3... looks like a nut with a ball in the middle of it... I just noticed your from GA... you ever been to Jeff Garmens shop here in Griffin? hes got one of his rides in diesel power right now...
 

· Registered
Joined
·
160 Posts
Discussion Starter · #7 ·
im thinking if that spring is worn that the fuel pressure would allow it push all the way up allowing fuel to go back to the tank because its thinking its at max pressure... but does that explain why the obd3 or whatever it was... was saying that my max psi should be 16,000psi at WOT when the book says it should be 23,000ish?
 

· GA CUMMINS CREW PREZ & Captain of the USS FAILBOAT
Joined
·
5,525 Posts
that could be a fca problem, you pumped is limited to 180 psi before it starts flowing back into the tank, and yes, i have been to jeffs, great guy, had a dyno day there last year... :thumbsup:


i noticed you just joined also.... welcome to the team go check out the chapter site, click the link in my signature....
 

· Registered
Joined
·
160 Posts
Discussion Starter · #9 ·
commanded rail pressure :thumbsup:

i bet it had something to do with the DIY mod you did. no offense. try replacing the fca.

Dang sorry just saw your post... guess i passed by it... yeah sucks... im kinda thinking the same thing... either i F'ed it up or its the overflow valve... i really dont think its a bad injector anymore though... but i guess it still could be... i wouldnt think a leaking injector would cause me to loose 8,000psi though... unless like all of them were leaking... with my luck anything possible...
 

· Registered
Joined
·
160 Posts
Discussion Starter · #10 ·
that could be a fca problem, you pumped is limited to 180 psi before it starts flowing back into the tank, and yes, i have been to jeffs, great guy, had a dyno day there last year... :thumbsup:


i noticed you just joined also.... welcome to the team go check out the chapter site, click the link in my signature....
Yeah hes pretty cool... ive talked with him alot about it and hes probly tired of me bugging him but i dont have the extra dollars to just drop it off with him... he got his $3,400 from me when i dropped second gear last summer... got his tranny and TC in it now... should be good for alllooonnngg time... he thought it was a injector for sure for the last 2 months till i hooked up the computer and told him what happened... he thinks maybe the FCA and i should swap it out with another truck and see what happens but i dont know anyone with another cummins... thats not a 12v anyway... asked him about the overflow valve and he thought i was talking about the relief valve so dont guess he knows much about the COV... or else he knows it as something different... he does that dyno days i think once a year... should be coming up actually i think? maybe ill have mine fixed... lol... never been dynod... dont have a programmer yet but i was able to bark 2nd still before this problem... just abunch of small stuff... and his tranny...
 

· Registered
Joined
·
160 Posts
Discussion Starter · #11 ·
Well i took the FCA out again the other day... played with it for awhile... i read that if you shake it and it rattles then its good... i can shake mine and get nothing but if i pop it on my hand itll rattle... so i dont know if thats the same thing... the little piston i did the mod to still slides back and forth fine... So heck i dunno... could be anything i guess... i hate to just start buying parts for it and see what happens... dont have any buddies around here i could pull there FCA for a min off there cummins... im a loner... the rest drive dang powerstrokes... that would tell me id its that or not anyway... so the COV valve is kinda out of the questions also with only 16 thousand psi at WOT... doesnt really affect rail pressure huh? So probly FCA or would a bad injector even cause me to have that low of pressure?
 

· Registered
Joined
·
160 Posts
Discussion Starter · #14 ·
fuel override test? not sure i remember seeing that... remember doing a test where we cut off each injector but not sure what it was called now... how do you do a fuel return test? ill search it right now but ive never came across it before? Thanks!!
 

· Registered
Joined
·
76 Posts
To do a fuel return test disconnect the return line quick connect easiest through the wheel well(at least on mine). Connect a hose to the hard line. Remove the banjo bolt on the back of the fuel filter housing the one closest to the block. You will need a banjo bolt with a hose fitting on the end of it. Connect a hose to the banjo fitting. Stick the ends of the hoses into something measurable. Run the truck until you get flow from both hoses, then measure flow for the minute at idle. You're allowed 180ml for the injector return, I got around 50, 60 after I did my injectors. And you're allowed 1000ml for the pump return, if it is greater they say the cascade overflow valve is bad.

Also there should be no leakage(flow) at the pressure relief valve at 16,000 or for that matter 23,000.
 

· Cummins Fanatic/INJECTION PUMP TECH ADVISOR
Joined
·
419 Posts
Are you just checking the rail pressure with no load at WOT? If you computer is only asking for 16,000 psi and you have no codes then you are not testing the system correctly. If this is the issue then you would be looking at a sensor not an actuator like the FCA.

What exactly is your problem?
 

· Registered
Joined
·
160 Posts
Discussion Starter · #18 ·
havent had any luck yet... i had ONE buddy with a 03 cummins and he was gonna let me pull his FCA and swap it onto mine but i got there and we stripped out 3 torx bits and his torx bolts so dang it man... BUT i do have a buddy who blew his motor in his 06 and dodge wont cover it of course so his dad works at LKQ and got him the hook up on a motor that had caught fire and melted everything around it... So hes going to stick that block in his truck with all his crap around it... thing is the motor only had 26,000 miles on it and hes got aftermarket injectors so hes keeping his... he has to have some to go back as a core so im going to pull the injectors out of the burnt motor and stick them in mine and stick mine in the box with the rest of the parts to that one... Cool thing is it aint costing me a dime!!! hes not out anything so he doesnt want anything... he already sold the core block for what he got the burnt motor for... So... by the end of this week i should be running new injectors and maybe that will help... maybe it wont... either way i got 150,000 and 26,000 is waaayyy better for free... even better when they cost so dang much... but after this i will let you guys know what happens!! sorry it took awhile to write back... i dont check this every day cause honestly i dont hear much back often.... well as often as the cherokeeforum im in... lol...
 

· Registered
Joined
·
160 Posts
Discussion Starter · #19 ·
Are you just checking the rail pressure with no load at WOT? If you computer is only asking for 16,000 psi and you have no codes then you are not testing the system correctly. If this is the issue then you would be looking at a sensor not an actuator like the FCA.

What exactly is your problem?

no load at WOT... just when it was sitting in the shop... we went down the road and he watched it but i didnt so i couldnt tell ya... im pretty sure it only hit 16,000 psi also... or else he would have said something... the computer says something like set PSI which goes up along with your actuall PSI as you slowely press the gas... this is where your fuel pressure is and the set is where the computer says it should be... both are pretty close to each other which is right... but it only went to 16,000 psi the whole time... for less then a blink of a eye it jumped to 24,000ish but then went instantly back to 16,000ish... like i didnt know what happened at first it was so fast... and no theres no codes... but i think its fool proof testing the fuel pressure since its a computer you just plug in and click "fuel pressure" or whatever... Thanks for the help guys!!
 

· Registered
Joined
·
160 Posts
Discussion Starter · #20 ·
To do a fuel return test disconnect the return line quick connect easiest through the wheel well(at least on mine). Connect a hose to the hard line. Remove the banjo bolt on the back of the fuel filter housing the one closest to the block. You will need a banjo bolt with a hose fitting on the end of it. Connect a hose to the banjo fitting. Stick the ends of the hoses into something measurable. Run the truck until you get flow from both hoses, then measure flow for the minute at idle. You're allowed 180ml for the injector return, I got around 50, 60 after I did my injectors. And you're allowed 1000ml for the pump return, if it is greater they say the cascade overflow valve is bad.

Also there should be no leakage(flow) at the pressure relief valve at 16,000 or for that matter 23,000.
ive got the rail return pluged so nothing is going back through if its good or bad... actually i think its bad cause i pulled the banjo bolt and started the truck and alittle bit was coming out at idle... so i just pluged it till i fix this... i may also swap the cascade overflow valve out with the motor my buddies got just incase... its all metal so it should be fine... all the plastics on the motor were burnt up though... but this will be easier then doing that test i think since now i got one i can get for free...
 
1 - 20 of 20 Posts
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top