Lift Pump Issues

[99 cummins]

When I started the truck a few days ago I noticed the fuel pumps didn't turn on during the wait to start period like usuall. Just figured it was a fluke and didn't think anything about it. Truck started right up with no problem, holds pressure at the same psi as always. Everything works just fine the pumps just don't come on when they are supposed to for priming.

Next day they are back to working just fine again.

Now today I'm delivering a trailer and on the way home lost all pressure, Fluctuated for a few minutes and then nothing. Keep in mind I have twin LP's on this, so I know they didn't just both quite at the same time and the in-line fuse I have on them and the Relay are both good. So it has to be the ECM or trigger wire. Lookin for ideas here.

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99 Quad Cab, 4wd, Comp Box W/Pump Wire & Boost Elbow installed, K&N Air Canon, MBRP exhaust, Twin PE 4200 High Pressure Fuel Pumps W/Fleetguard inline filter, Isspro EV Pyrometer, Boost Guage, Fuel Pressure Guage, DT Pro Fab Trac Bar, South Bend 13-1.25 Con O Clutch, Royal Purple Synthetics all around

374.2/846.7 at 30psi

[Mopar1973Man]

Since you are using 2 pumps in series of each other if one pump fails they both fail. The working pump cannot push and/or pul fuel through a dead pump.

So if it was me I would bump the starter to trigger the 25 second run period and verify both pumps are working properly. You should see 12V at both and both should humm pretty good. Pressure gauge will also verify that both are working...

So remember if 1 fails you whole system fails...

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Michael Nelson - 2002 Dodge Cummins

[99 cummins]

These pumps are side by side, not in series. They both feed independantly of each other as far as fuel goes. The only place they feed together is from the trigger and power from the battery.

I need some quick help on this. I'm supposed to already be headin cross country movin the first load.

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99 Quad Cab, 4wd, Comp Box W/Pump Wire & Boost Elbow installed, K&N Air Canon, MBRP exhaust, Twin PE 4200 High Pressure Fuel Pumps W/Fleetguard inline filter, Isspro EV Pyrometer, Boost Guage, Fuel Pressure Guage, DT Pro Fab Trac Bar, South Bend 13-1.25 Con O Clutch, Royal Purple Synthetics all around

374.2/846.7 at 30psi

[Mopar1973Man]

I would disconnect from the ECM trigger lead and hook straight to 12V and see if the relay trggers power for the pumps. You might have a bad relay or a bad trigger lead from the ECM...

So if hook the relay trigger lead to 12V+ it should pop on if it does put a rocker switch on the new trigger lead and this will allow you to turn the pumps on and off to move... Remember to turn ON the pumps before STARTING and turn off the pumps AFTER shutting down...

OR...

Take the trigger lead from the relay to the fuse panel inside the truck and hook up to a keyed fuse that shuts off with the key and is on in the run position...

Couple of idea...

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Michael Nelson - 2002 Dodge Cummins

[99 cummins]

If this is an ECM problem, will it keep affecting other things or will this be an issolated problem. With all these road miles coming up,I don't want to be 800 miles from home with a 20,000 pound trailers or horses behind me and have issues with this. If need be I know I can easily hook a switch up here but I am slowly sliding down this path where nobody but me will even know how to drive this truck. I would rather fix it right if I can. I already have a tractor that even after I start it nobody else can figure out how to use it because of all the jerry riggin on it. Works great for me.

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99 Quad Cab, 4wd, Comp Box W/Pump Wire & Boost Elbow installed, K&N Air Canon, MBRP exhaust, Twin PE 4200 High Pressure Fuel Pumps W/Fleetguard inline filter, Isspro EV Pyrometer, Boost Guage, Fuel Pressure Guage, DT Pro Fab Trac Bar, South Bend 13-1.25 Con O Clutch, Royal Purple Synthetics all around

374.2/846.7 at 30psi

[Oregonpharmer]

If you bypass the ECM power feed to the transfer pumps and go with 12 volts directly you run the chance of kicking the processor on the VP44 into its failsafe mode if you drive it that way. Doing the bypass for a test is just fine, as that will narrow the possible failure point, but try to not drive with the voltage bypassed.

If you are a road salt state, I would check my grounding lugs for the aftermarket fuel pumps.

[99 cummins]

Thanks to all. I think I have things back going again, but not to confident. Think I must have picked up some bad fuel somewhere along the trip. I wired right off the battery and crawled under the truck. I could hear the pumps motors trying to run but nothing happening. Changed the fuel filter and gently tapped on the Pumps with the biggest pipe wrench I have and whatever the problem was they broke lose. When I hooked the trigger wire back up to the ECM were back to working fine now, again, for now.
I'm still looking for opinions on what happened here though, in case it is still a problem in the future.

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99 Quad Cab, 4wd, Comp Box W/Pump Wire & Boost Elbow installed, K&N Air Canon, MBRP exhaust, Twin PE 4200 High Pressure Fuel Pumps W/Fleetguard inline filter, Isspro EV Pyrometer, Boost Guage, Fuel Pressure Guage, DT Pro Fab Trac Bar, South Bend 13-1.25 Con O Clutch, Royal Purple Synthetics all around

374.2/846.7 at 30psi

[99 cummins]

Still gettin some strange fluctuations in fuel pressure. Hasn't fallen below below 15psi yet but it never used to move at all. Still Need some ideas here.

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99 Quad Cab, 4wd, Comp Box W/Pump Wire & Boost Elbow installed, K&N Air Canon, MBRP exhaust, Twin PE 4200 High Pressure Fuel Pumps W/Fleetguard inline filter, Isspro EV Pyrometer, Boost Guage, Fuel Pressure Guage, DT Pro Fab Trac Bar, South Bend 13-1.25 Con O Clutch, Royal Purple Synthetics all around

374.2/846.7 at 30psi

[Oregonpharmer]

Drop some Power Service 911 in the tank and see if you have a bit of ice or paraffin in the pump housings that needs to be dissolved.

If the transfer pumps are working flawlessly and there is no ice or paraffin built up, then I would suspect the VP44 front housing fuel circuit diaphragm has failed and is letting fuel bypass the injection pump pressure circuit. Unfortunately, if that occurs it is time for a rebuild.

That front VP diaphragm fails if the truck is run without pressure to the injection pump, and sometimes it only takes an instant on one with some time on the pump. If you do need a rebuilt VP, look for one with the new linered rear housing that keeps the case from eroding around the timing valve.

[99 cummins]

Originally Posted by Oregonpharmer

Drop some Power Service 911 in the tank and see if you have a bit of ice or paraffin in the pump housings that needs to be dissolved.

If the transfer pumps are working flawlessly and there is no ice or paraffin built up, then I would suspect the VP44 front housing fuel circuit diaphragm has failed and is letting fuel bypass the injection pump pressure circuit. Unfortunately, if that occurs it is time for a rebuild.

That front VP diaphragm fails if the truck is run without pressure to the injection pump, and sometimes it only takes an instant on one with some time on the pump. If you do need a rebuilt VP, look for one with the new linered rear housing that keeps the case from eroding around the timing valve.

Thanks OP. I just changed out the VP44 last year with a Blue Chip New pump. The ice or pariffin may be an issue here. A couple of tanks prior to this starting I was using PS every tank full. I had changed over to just 2 stroke oil and two tanks later this started up. May just be coincidence, I don't know. Just find it hard to beleive that two pumps that had worked flawlessy for a year now both start giving me problems at the same time.

I am also convinced that it is an issue with the LP's because you can hear the difference in how they sound when the pressure fluctuates. I also have a pressure guages mounted just after each pump and I could watch it jump as the motors sounded like they were freeing up. It sounded just like they had a blockage of some sort working it's way through.

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99 Quad Cab, 4wd, Comp Box W/Pump Wire & Boost Elbow installed, K&N Air Canon, MBRP exhaust, Twin PE 4200 High Pressure Fuel Pumps W/Fleetguard inline filter, Isspro EV Pyrometer, Boost Guage, Fuel Pressure Guage, DT Pro Fab Trac Bar, South Bend 13-1.25 Con O Clutch, Royal Purple Synthetics all around

374.2/846.7 at 30psi

[Mopar1973Man]

Ok.. Lets start simple...

Do you have stock fuel pick up unit? Is the screen intact? Is the screen plugged up?

Do you have debris in the fuel lines? (Rotten rubber, trash, etc)

What kind of pumps do you have? How old are they? (miles / Time)

I would start over again and inspect from start to finish. I would start at the tank and inspect the fuel pick up unit and the inside of the tank. (Yes this requires lifting the bed) After you sure the pick up and the contents of the tank are fine move foreward up the line. Make sure you don't have rubber flaking off and jamming up you LP pumps. I would disconnect all line and blow them out. (Yes. Now you got to reprime the system.) But you'll know the lines and the pumps at this point are clean. If you haven't change your filter do it now and drain the filter housing in to a container and inspect the fuel for debris, water, gelling, etc...

As fore the pressure there is a OVERFLOW VALVE on the VP44 pump. It can be tested with a blow gun. Sometimes the check valve will hang open and dump all the pressure back to the tank.

Something you wrote maybe you should follow your own advise...
Fuel System Troubleshooting Guide

You taugh me alot by writing that article...

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Michael Nelson - 2002 Dodge Cummins

[R-N-R]

I popped a fuse on the frame pump once, the truck kept running fine with the motor mounted pump but with less pressure. A couple of weeks ago I tried filling up with Super Diesel. The pump was running really slow so I bailed and finished up with regular diesel. About 5 minutes later the truck started gagging on the highway, pressure was gone. The fuse looked fine, I used the bypass and the trucks is running fine, albeit at a lower psi. The pump (carter) must have quite with the vanes blocking fuel. The first time the vanes must have been "open" when the fuse blew. My first LP to go out died slowly. Is there any chance yours is dying slowing with the vanes in different positions when the failure occurs?

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'02 2500, 2WD, 4.10, QC LB Cap, Bilstein, Gauges
DTT, AFE, PDR Boots ARP, B1-2, MagnaFlow, GRAND ROCK, Drag Comp, Regulated Fuel Delivery, IIS HRVP, M4.5, HTT
28' 6500# Sunline TT, Hensley, Prodigy