VP failure?

[Matt0matic]

Trying to diagnose a my truck dying while driving down the freeway.

 

Truck is a 1999 Cummins 5 Speed in a 83 Ford.

VanAken Box

1/2 Napa fuel strainer before the Fuel pump

Walbro 255 Fuel Pump

20 Mic Water Separator w/drain Donaldson P558000

3 Mic Fuel Filter Donaldson P551313

1/2 fuel line from the sump to VP

 

 

 

 

The Fuel system is all brand new from tank to the filters to the 1/2 line to the VP as of 6 months ago.

 

Here is how yesterday went:

 

Brother gave me a bottle of Power Service Diesel Kleen and figured why not try it, I haven’t had a heavy trailer on in a while and have been using it on short trips. Filled up 38.8 gallons of fuel and poured in the dosage for 40 gallons.

 

Loaded up a trailer full of wooden spools and moved them to another job site 30 miles away I get literally one mile from my destination and the truck dies after I let out of the throttle coming off the freeway. Had 20psi fuel pressure when it died; after that it would just turn over and not fire when ignition was engaged.

 

I get a coworker to pull me off the freeway and I put the truck in gear to slow down to keep from hitting him, at this point the truck fires up from the motor turning over while in gear and remains running. I end up being able to drop the load of and return back to the  shop 30 miles away without a hiccup, same 20psi fuel pressure.

 

End up running some errands and total another 40miles on the truck until it is time to go home at which the truck dies again as I let out of the throttle on an off ramp en route to the yard. Had the boss pull my truck the remaining one mile to the yard- and again the truck wouldn't fire with the ignition but it would fire from being pulled and slipping it into gear. Still have 20psi showing on the gauge.

 

Today after work I get to take a look at the truck- flip the key to run, where normally it jumps right up to 20psi BUT this time it slowly climes to 20psi. I check the voltage at the pump and it is only pulling 8.5v, disconnect the pump and I have 12.5 at the wire. I replace the pump with a new on and now it pulls 9.8v- but it still is slow on reaching 20psi. After bleeding the air out of the system the truck fires up and runs for about 3 mins surging the whole time and eventually dies on its own accord.

 

My next step is to replace the fuel filters and if that doesn’t clear it up going to take the wiring harness of the VP and just give it power and ground to rule out faulty IP.

 

Any suggestions or advice?

[mopartechnician]

Verify pressure with another gauge. Kinda wondering if the computer in the vp is going bad. Pour water over the top of the vp when it acts up and see if it starts

[mulcher812]

well do you still have the APPS sensor? If so I think i would check voltage to it also.

[Matt0matic]

Timbo APPS sensor on the truck which replaced the failing OEM, I'll check function tomorrow.

[Matt0matic]

Good idea on a second gauge, I'll report back with new readings ASAP.

[Mopar1973Man]

APPS sensor doesn't really control idle. When the IVS grounds for idle position then the ECM uses its own internal software to manage idle speed. So even without a APPS sesor present the truck will still start and idle.

 

Basics... Error codes and fuel pressure tested with a mechanical gauge.

[rancherman]

seeing this is a transplant, I'll bet you don't have a cel wired in, and probably have codes in the

ecm?

My 2000 did exactly what you are describing, ran for a bit, died, didn't restart until cold, repeat.

it was my vp44, or at least the electronics in it.

[Dieselfuture]

I don't know much about internals of vp, but it makes me think your rotor inside vp or something is getting stuck when you put it in nutral and cutting of fuel supply internally, and if you pull it with another truck and get it in gear you force it to turn again and it runs.

[Mopar1973Man]

I don't know much about internals of vp, but it makes me think your rotor inside vp or something is getting stuck when you put it in nutral and cutting of fuel supply internally, and if you pull it with another truck and get it in gear you force it to turn again and it runs.

 

http://articles.mopar1973man.com/2nd-generation-24v-dodge-cummins/25-fuel-system/437-bosch-vp44-injection-pump-exploded-view

 

Give a clue. But I can tell you if the parts are damaged it would be stalling all the time. All parts are harden steel.

[JAG1]

I know some guys with the screen strainer in front of the lift pump have had clogs show up there.

 

I would have the 20 micron prefilter before the lift pump instead/ removing the screen. this protects the lift pump and allows easy changing of a filter there instead. Check screen, remove and see if there is free flow of fuel from inside the tank as well or if there is an old fuel filter in there or varnished screens.

 

With gauge responding slower than usual I think is a clue to what's happening.

Edited May 13, 2014 by JAG1

[Dieselfuture]

http://articles.mopar1973man.com/2nd-generation-24v-dodge-cummins/25-fuel-system/437-bosch-vp44-injection-pump-exploded-view

 

Give a clue. But I can tell you if the parts are damaged it would be stalling all the time. All parts are harden steel.

Man, vp looks more complicated than the engine itself. I think I'll have no problem rebuilding an engine and don't even feel like looking that hard at vp pictures giving me a headache already. Lol.

[Mopar1973Man]

Strange enough I pull it all apart and put it back together and sitting on my shelf in the shop for future needs.

[Matt0matic]

Bypassed the filter system with some 1/2" line and a remote 5mic filter and the truck fired up after bleeding the system, including injectors.

I replace all filters and reinstalled the fuel system and the truck runs like it did prior to this episode fuel pressure jumps straight up to just under 20psi by both my mechanical gauges and holds there under all driving conditions.

I cut open the water/fuel filter and it looked brand new with no visible wear- to me it looked brand new; the 3 micron Donaldson on the other hand was slightly discolored compared to the fuel/water, but other than that there was nothing I could see obstructing flow. The only filter I wasn't able to inspect was the 1/2" fuel screen prefilter before the pump. (But it got replaced before I bypasses the system and didn't cause an improvement.)

If I had to take a wild *** guess: either a bad batch if fuel or the Diesel Kleen injector cleaner causes something to go wrong.

[Matt0matic]

Or I somehow pumped air into the injector and didn't have the VP bled correctly; but, I don't understand how that could happen with a daily driven vehicle.

[Matt0matic]

Still running without problems, I'm thinking the PowerService Diesel Kleen had something to do with the fuel filters clogging they were only 5-6 months old; or a bad batch of fuel.

[Mopar1973Man]

I personally don't suggest Power Service products. Causes more issues than it fixes.