well heres a long story that i cant figure out i have a 99 vin x and engine f 6.5l diesel i had a problem with my cruze it would hit 2g then drop to 650 and 2 again on a down hill making it a rough ride sooooo. some one told me the computer was bad cause my scanner would not give values so i took it to the dealer to program a new computer and it was worse the engine wouldnt idle below 1500 rpm with black smoke and every few seconds want to run away then come back down to 1500. with the new computer programmed for a 99. so i put my 96 computer in and it ran fine except for the security light on the dash so i figured out that the production date on the door said 3/98 thats not a 99 so when entering the scanner vin for id i used w for 98 and wala all my values came too and the dealer told me to change my injection pump so i changed my pump and my cruse stopped acting up and i was able to put my orignal comp back in the truck i had a problem of looosing power and on the highway it would shudder very bad it broke the 2 lower bell housing bolt heads right off. so the other night i got on the highway and put my foot down to merge and it fell on its face almost dying and then cleared up i found that where the old mechanical 6.2 advance arm would be on a db2 pump theres an electronic one with a 5 or 6 pin plug unsure of what it is .....was un plugged so i plugged it back in and now the truck is galuping just like it did before with lots of black some i have put the 96 computer back in to drive it cause its all i have and it has cleared it self please help i am so upset i dont even want this truck anymore it has been a whorrible experience give me my 96 7.3 back ....... so anyhow if any one can help please do cause im almost at my end...

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i guess im alone on this one im just gonna find it a new home thanks for ur help!

 

The apparatus on the side of the IP is the timing stepper motor.
The build date denotes a 98.

Often a bad PMD will cause the symptoms you describe,kit including a 6' extension harness,an aluminum heatsink a new PMD and a PMD resistor is required to to remote mount the PMD outside the underhood area=blow/behind the frt bumper or behind the grill on a rad support are common locations for remote mounting.

You haven't indicated any trouble codes,if any were present they could aid in diagnosis.

Please copy and paste the checklist in this link to your next reply:
Diagnostic Checklist version 2.0 [10-2009] - Diesel Place : Chevrolet and GMC Diesel Truck Forums

Then edit in the answers to the questions and the results of the required tests-blue highlights are links to how the tests are performed.

need more info on the problem and what you have done to diagnose it to give a reasonable answer.

Also please hit enter every once in a while to make your post easier to read.

 

it has the updated pmd on the fender well not made by standadyne i tried swapping out my

spare one and no change ran the same but

i have no dtc either kinda stomped here

 

Get going on the diagnostic checklist then if you please.

Also have you checked for DTC's or is the check engine light off leading you to that conclusion?

 

is it possible that the stepper being unplugged damaged the computer?
i checked for dtc no engine light and i have a snap on scanner

 

Unlikely the stepper hurt the ECM but is possible?

You need to do the checklist so we have something to go on.

 

The Diagnostic Checklist:
Please fill out to best of your knowledge.



1. Describe the problem you are having in detail:

2. Year of truck/engine.
3/98 but vin x says 99

3. Odometer reading (indicate miles or kilometers).
truck 270,000 engine rebuilt 10,000

4. Indicate the model number on the Injection pump (starts DS4 or DB2......).
ds4

5. Indicate if you know if it’s a 1500, 2500, 2500HD, 3500, 3500HD.
k2500

6. Do you have an EGR on the engine? (An F or an S engine code 8th VIN digit)
vin f no egr

7. Air Filter condition (visual check).
ok

8. Fuel filter condition (freshly changed, mileage since changed).
1000 miles on new filter

9. Location of PMD/FSD? (ex. on pump/remote over intake, behind bumper).
pmd located on driver inner fender well

9a. If remote mounted, describe wiring harness (homemade or purchased from which vendor). purchesed from vendor cant remember who

9b. Indicate the location and condition of the FSD/IP grounding wire.
right on to of ip

10. Outside Temperature (C or F). _32-38___f_ °

11. Service Engine Light while running?- on/off/intermittent
no light

11a. Service Engine light does glow during start/cranking/bulb check: Yes/No

12.Have you scanned for engine codes? Yes

12a. List exact results on engine codes.
no codes present

13. Condition of Battery terminals (removed, cleaned and tightened).
all above

14. Known condition and age of Batteries.
older

14a. Are batteries a matched set of same age? no

15. Condition of Major Grounds (removed, cleaned and tightened) yes

16. Does engine crank, or "turn over"? yes

16a. Does engine start and run? yes

17. If engine does not start- Crack injector line: do you have fuel? starts

18. Does your Wait To Start light come on? yes

18a.Number of seconds WTS light is lit.
7-10 sec depends

19. Engine Cranking speed (if you have an accurate tachometer). unsure

20. Are you experiencing Stalling?
only once

20a. Describe the event (upon startup only, down the road, hit a bump, etc...)

idled for 10 min went to drive away started up small hill and shut off wouldnt restart then sat for min it hesitated to start and then restarted an was fine the rest of the ride

20b. Do you notice loss of dash or instruments? no

21. Check turbo inlet and air filter for obstructions. ok

22. In a no-hot start, pour a bottle of room-temp water on the injection pump. Does it start now?
it starts hot or cold

23. Lift pump test - Describe results.

24. Upon cold start, does the radiator hose get hard quickly? No

25. Upon cold start, do you have excessive white smoke? No

26. Do you have excessive cranking time before the engine starts? No

27. Have you used the block heater? Does it affect engine starting? (only try for starting problems). n/a

28. Are all glow plugs in proper working order? yes 60 g ac delco

29. During hard acceleration, do you have excessive black smoke? No

30. Do you have any unusual exhaust smoke issues? lots of soot

31. Turbo check out - Pass

32. Indicate fuel that you are using:
#2 Diesel

32a. If running Veggie Oil fuel setup, indicate details of your conversion (homemade or packaged system). n/a

33. Are you using any fuel additives? If so, please list.
power service

34. Upon unscrewing fuel cap, do you have a large vacuum formed in the tank?
small vac

35. Do you have any service history available that might pertain to the problem you are having?
nothing doc in my records

36. Please indicate any modifications to the vehicle that might help us diagnose better.
only differance is i put 6.2 diesel heads when i rebuilt my engine wint 6.5 pistons nothing else diff

 

Need the results of the LP test.

PMD suspect,anywher under the hood is a bad location for PMD placement.

Also when PMD was remote mounted was heat transfer paste/pad used between the PMD and heatsink?

PMD torqued to 20-25 inch pounds on heatsink?

 

yes pmd was replaced with a mew one to rule out this problem and there was no difference

 

LP test results?

Most of your difficulties would lead me to the APP or the PMD,IP but nearly all should throw a code.

Condition of major grounds refers to the 3 ground wires at th rear of the intake mounted to a stud-are they clean and secure?