need help on engine dying

[dieseltech06]

Hey all, I have a 2002 cummins 2500 SLT, manual trans, 4X4. The problem I have been having that just started a few months ago is the engine with die and then come back on going down the highway. The engine will do this on off on off surge like someone is turning the key on and off very fast. This will happen with the throttle pedal and or the cruise control. The fuel system is solid with a fass fuel pump and I have verified 15psi at my VP44. I have cleaned all grounds and verified wiring connectors are tight and problem free. I have no codes and have verified that I have no ripple effect coming from my alternator. I stopped in at a dodge performance place and went for a road test with a scanner hooked up. The tech showed me that in the PCM screen real time, the fuel shut down was changing from on to off very fast and causing our surging problem. I'm at a loss being a diesel tech for caterpillar I have tried everything that I can think of. Can someone also clarify what the ECM takes as an input for throttle. IE ( APPS and Cruise control) Or does the PCM control cruise control and the ECM controls throttle from the APPS only. Thanks

[Cumminz]

Do you have a stock VP44? The only things I can think of are hooking up a clear line between vp44 and lift pump and check for air. Other than that try the "Hot wire test" on vp44 for proper computer function. http://bluechipdiesel.com/vp44_diagnostics.html#noStart3  Also the APPS signal is sent to the ECM and then goes to PCM. Cruise control i can't remember off top of my head. I think just to ECM.

 

NO START TEST #3

HOT WIRE TEST - THE "FOR SURE TEST" TO DETERMINE IF THE VP44 IS WHY THE ENGINE WON'T START

It is very rare, but possible, for a problem with the wiring harness or the CAN Bus wires to prevent the engine from starting, so if you want to be 100% sure it IS the Injection Pump causing the no start, follow the following directions exactly, to be sure of not damaging a possibly good pump. This test POSITIVELY eliminates the possibility of overlooking an electrical problem caused by other components 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 harness or CAN bus wiring to the ECM telling or causing the engine to not start. Call me for help if this is the case.

Edited March 27, 2016 by Cumminz

[TFaoro]

To me this sounds like a cam position sensor starting to die. When the engine receives no signal it cuts all fuel, then it comes back right away and fuels it. Do you notice your tach completely dying when it does this?

[dieseltech06]

I've checked for air in the return and its all clear so no air. I forgot to mention that it does this intermittently and runs great when cold. After warming up and running for awhile the dying comes back only with cruise control and then sometimes with the throttle pedal. All guages stay working and no warning lights. All is stock on this engine. 

[Dieselfuture]

If no codes and fuel and boost is good, could be injectors, A/C noise from alternator, bad vp44 fuse or something mechanical in vp that isn't throwing a code yet, grounds, if you have tuner unhook completely and try driving, maybe valve adjustment. 

[Mopar1973Man]

 

19 hours ago, dieseltech06 said:

The tech showed me that in the PCM screen real time, the fuel shut down was changing from on to off very fast and causing our surging problem.

 

Ummm... PCM doesn't control the VP44. I'm going to assume from this point ECM. So that leads me to believing there is a internal issue with the ECM. You could try and have it flashed again see if its software issue but it sound like a MOSFET or cracked solder joint is failing in the ECM.

[Hawkez]

Is your FP gauge in the cab and can you monitor it while driving?  I know you said you have 15 psi at the VP44, but when the truck is cutting in and out can you see what your pressure is doing?  What is the condition of  your fuel filter?

[hodag56]

I had a similar problem 2yrs. ago, it turned out to be the power to the lift pump from the ecm was intermitantly shutting off as soon as the engine warmed .If you have a away to test that while driving you would be able to see if that's what it is .Eventually my power to the lift pump quit , and I had to have my ecm rebuilt. If you think that's what it is you might find another ecm and see if that works .I think I had a bunch of codes when mine went out. Good luck those intermitant   problems are the hardest to diagnose. Make sure you find a reputable rebuilder because there are a lot of bad ones out there.

[twarnock01]

i had the same symptoms i was getting codes and after checking all wiring (with alot of help from this forum) determined it was a bad ecm i borrowed an ecm for testing. then a whole new symptom appeared doing exactly as you describe going down the road the truck would intermintently shut off and come back to life no codes no change in gauges etc i was going nuts cleaning grounds resetting apps new alt (mine was bad) which probably fried the old ecm. i ended up picking up a used ecm and had it flashed to my truck using a smarty problems all gone i'd be willing to bet your ecm is on its way out.

[Silverdodge]

I had a issue like this it ended up bring a fuel relay gone bad

13 minutes ago, Silverdodge said:

I had a issue like this it ended up bring a fuel relay gone bad

I got code 1689 I think and I found an article on here about it being a relay 

[dieseltech06]

Thank you for all your responses and support guys. I have located a test engine ecm that a guy will loan me in town so once I get that put in, hopefully Thursday night we will see how the truck runs the rest of the week and weekend. I will keep u posted on how it turns out. Happy wrenching!

[dieseltech06]

Update. The ecm has been in for two weeks now and no probs so

i think I got her licked. Since the ecm is out of an 01 I'm going to dodge to flash it with the latest software.

The ecm was out of a blown up engine so the guy gave it to me as long as I bought an exhaust system from him. No prob I said

[dripley]

Good to hear.

[dieseltech06]

Well dodge says this ecm

that i have is unprogramable. Depending on the year some could get flashed once and some are re- flash able. Anyone have any onsite on this topic. They wanted to

sell me a 1500 dollar new ecm and I said hell no. 

The truck runs good, just wanted to get the latest software in it

[dripley]

I have no idea on the flash ability of your ECM. But Dodge offering a fully flashed ECM for $1500 sets me back.