Engine/Transmission (1998.5 - 2002) truck died - diagnosis?

[SS]

Hmmm... truck stumbled and died on the way to work.



It died similarly about a year ago and it was the poor COMP tap to the injection pump. So I temporarily repaired it with a crimp-on butt connector (and never got around to permanently repairing it). Last month it died and I assumed it was that it lost contact at the butt-connector - wiggled it to get a fresh contact and it started right up. So today I soldered it, but it still won't start. Codes 1693, 1694, 1689, and 0237 (have a boost sensor issue also). 1694 would seem to indicate lost signal to injection pump.



Here's the odd parts: The "wait to start light" is acting strange - sometimes extinguishes right after key on, sometimes comes on while cranking, sometimes seems normal. Also, the tach and oil pressure gauges occasionally stay high after a no-start when the key is left in the on position.



I soldered in about a foot of extra wire - could that be an issue to the injection pump signal? Or does it sound like ECM? Lift pump sounds to be working, though I have to go check flow. Just not sure that is the problem and looking for thoughts - thanks.

 

[SS]

Update:

Update: I jumped the fuel injection pump pin #7 to power and pin #6 to ground and the truck starts and idles perfectly. I take that to mean nothing is wrong with the pump? Interestingly enough, the "wait to start" light operates normally when the injection pump is jumped. So... still confused whether it's an ECM issue or now a wiring issue. Anybody have an experience like this? Thanks.

 

[Graphic man]

sounds to me the ECM is not supplying the power to the pump if you did the jumper and it works



maybe someone can chim in and confirm it.





Scott

 

[SS]

Thanks Scott - that's what it sounds like to me too. Plus with the dash acting a little flaky, I was leaning towards ECM. I'm not real fired up to go buy one to find out though. Maybe I can talk one of my buddies into borrowing theirs for a test - "Yeah my truck has an electrical problem so can I use your ECM?" LOL



Any other suggestions? Almost all my searching points to VP44 or ECM.

 

[SS]

Bueller? Anybody?



Guess I'll try to get to the ECM tomorrow if I can...

 

[SnoKing]

Have you cleaned all the ground connections. And resetted the connectors at the ECM and PCM? SNOKING

 

[SS]

Crazy holiday season schedule...



Anyway - I did remove the grid heater relays and cleaned all of the connections which were quite corroded. Did the same at the grid heaters though they appeared fine. Removed and cleaned IAT which needed to be done. Removed the injection pump connector and cleaned it with contact cleaner and used dielectric grease when reassembling. Same with the Cummins ECM connector. Didn't check the PCM connectors but will do that next. I will go after the battery grounds right now also.



Now I can't get the transfer pump to run (Thought for sure it was last week... maybe I'm losing it. ) Checked the connector and get 8. 8V when keyed on or cranking. Truck batteries are fully charged. The wiring diagram appears to show power coming directly from the ECM, which I guess wouldn't have to be 12V. Can I jump it with 12V to check if it's operating?



Any other suggestions on specific connectors/contacts to clean? Or other areas to check?

 

[SS]

Batteries are a month old - when I installed them I cleaned all the terminals and coated them with protective spray. Main battery grounds cleaned and reattached. Small ground screws removed, wire brushed, and reattached. I could not get either connector apart on the ground wires from the passenger side battery to the ECM and the PCM (which of course seem the most likely culprit if it is a ground issue). Anyone had issues there? Causing poor ECM behavior?



PCM connectors also sprayed with contact cleaner and coated with dielectric grease.

 

[mhenon]

Can I jump it with 12V to check if it's operating?

You can not only jump it with 12V. . you could put a relay in place of the ECM voltage and run the pump right off the battery. I got rid of all my weird LP problems after doing just that.

Mike

 

[SS]

put a relay in place of the ECM voltage and run the pump right off the battery

Thanks - that will give me a way to at least check it.

 

[ILIANBG]

SS, I just fixed my truck, and I had pretty much similar problems, except mine did not die. Are sure the third code you posted was 1689? My truck set codes 1693, 1694 and 1698. I end up spending quite a few $$. Found out it was a bad ECM. I was not hoping for that one, but that's my luck. Let me know what you find.

Ilian

 

[SS]

Definitely 1689 - looks like it's a lost communication between ECM and injection pump. 1694 is also a possible ECM communication issue.



Maybe two years ago I had a couple of instances where the gauges all went to "0" and there was a "no bus" message on the odometer. Not sure that's related though - it's never happened again.



I have read a few of your posts in my search. So you replaced the ECM and all is well?

 

[SS]

Ecu!

Swapped ECU's with a like truck and appears to have fixed the problem. I will post up when I get a replacement ECU to confirm. Thanks to those that provided advice.