[waynesmobile]

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.1995
3. Odometer reading (indicate miles or kilometers).85781 miles
4. Indicate the model number on the Injection pump (starts DS4 or DB2......).----?
5. Indicate if you know if it’s a 1500, 2500, 2500HD, 3500, 3500HD.--- 2500HD
6. Do you have an EGR on the engine? (An F or an S engine code 8th VIN digit) VIN code F
7. Air Filter condition (visual check). Good
8. Fuel filter condition (freshly changed, mileage since changed). changed since problem started.
9. Location of PMD/FSD? (ex. on pump/remote over intake, behind bumper). PMD
9a. If remote mounted, describe wiring harness (homemade or purchased from which vendor).
9b. Indicate the location and condition of the FSD/IP grounding wire.
10. Outside Temperature (C or F). _90____ °F

11. Service Engine Light while running?- on/off/intermittent ---Intermittent
11a. Service Engine light does glow during start/cranking/bulb check: Yes/No --Yes
12.Have you scanned for engine codes? Yes/No--- Yes
12a. List exact results on engine codes.---DTC18----DTC35

13. Condition of Battery terminals (removed, cleaned and tightened).Yes
14. Known condition and age of Batteries.--Good 2 years old
14a. Are batteries a matched set of same age?---Yes
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? Yes/No
18. Does your Wait To Start light come on?---Yes
18a.Number of seconds WTS light is lit.
19. Engine Cranking speed (if you have an accurate tachometer).

20. Are you experiencing Stalling? ---Yes
20a. Describe the event (upon startup only, down the road, hit a bump, etc...) It varies, sometimes on startup, traveling at any speed, if you are stopped or traveling slow the engine will die if you are up to speed the truck jerks real hard and the check eng light comes on.
20b. Do you notice loss of dash or instruments?---No
21. Check turbo inlet and air filter for obstructions. ---Clear
22. In a no-hot start, pour a bottle of room-temp water on the injection pump. Does it start now?
23. Lift pump test - Describe results. found bad oil press switch and replaced/ no help The lift pump flows good and has good pressure.

24. Upon cold start, does the radiator hose get hard quickly? Yes/No ---No
25. Upon cold start, do you have excessive white smoke? Yes/No---No
26. Do you have excessive cranking time before the engine starts? Yes/No --No
27. Have you used the block heater? Does it affect engine starting? (only try for starting problems).
28. Are all glow plugs in proper working order?
---Yes
29. During hard acceleration, do you have excessive black smoke? Yes/No --When the check engine light is on it smokes.
30. Do you have any unusual exhaust smoke issues?--No
31. Turbo check out - Pass/Fail--Pass
32. Indicate fuel that you are using: Bio-Diesel, #2 Diesel, SVO/WVO, other--#2 diesel
32a. If running Veggie Oil fuel setup, indicate details of your conversion (homemade or packaged system).
33. Are you using any fuel additives? If so, please list.--Two stroke oil TCW-3
34. Upon unscrewing fuel cap, do you have a large vacuum formed in the tank? Yes/No--No
35. Do you have any service history available that might pertain to the problem you are having? Injection pump was replaced @ 28071 miles 1997.
36. Please indicate any modifications to the vehicle that might help us diagnose better. all stock
__________________

Does anyone have any suggestions, or should i get a new injection pump?

Thank you very much.
Wayne

 

[FloridaHorseman]

You didn't specify a remote location for the PMD so it's still on the IP? You would do well to install a new PMD w/remote kit and heat sink before condemning the much more expensive and labor intensive IP. Intermittent PMD failure has the symptoms you're experiencing. But so does a restriction in the fuel line causing fuel starvation under driving conditions. A vacuum condition in the fuel delivery could be responsible for the Optic Sensor "seeing" air and throwing those codes. You cannot know fuel "pressure" under load just by judging the flow rate from the water drain or bleeder valve at idle. All that indicates is the lift pump is working. Tee'ing in a fuel pressure gauge at the IP inlet hose and extending it to the windshield cowl to observe while driving is invaluable for isolating fuel delivery problems from PMD/IP problems. Note the fuel pressure as the stall occurs. If you have at least 1-2 PSI of pressure when the engine quits it's probably PMD/IP related. IF pressure drops to or stays at zero prior to the stall a clogged fuel strainer sock in the fuel tank would become highly suspect.

Even if it's not the PMD now, if you're gonna be a 6.5L pilot you need the PMD relocation kit and a SPARE working PMD as much as you need a spare tire. The PMD is the Achilles Heel of the 6.5. ~FH

 

[HeavyChevy95]

Read

 

[waynesmobile]

Thanks for the great information...
I hooked up a pressure gauge on the fuel system and ran it in the drivers window. Test driving the truck gave me 5 lbs at idle 4.5 lbs at 55 mph. Under full throttle from 0--70 mph 2lbs-- 1lb. When I turned the engine off I waited 5 min and still had 3 lbs. A paying customer came in so I didn't get a chance to try a new PMD.

Thanks
Wayne

 

[FloridaHorseman]

That's good fuel pressure. Keep an eye on it when the truck eventually stalls. If the pressure is still at or above 2 PSI when it happens the problem is most likely in the electronics. ~FH

 

[waynesmobile]

The engine stalled once while idling and the fuel pressure did not change and it set a check eng light at 55 mph and the fuel pressure did not change.

Thanks

Wayne

 

[waynesmobile]

I finally got a chance to try a new PMD and it still does the same thing. So I ordered a rebuilt injection pump.

Thanks for all your help.

Wayne.

 

[waynesmobile]

I installed a rebuilt injection pump (GM) and the truck runs great for a while then jerks real hard and sets DTC 18 & DTC 35 any ideas?

Thank you
Wayne

 

[JMJNet]

Have you time the new IP?

 

[waynesmobile]

Yes I timed it with a tech 1.


Thanks.

Wayne

 

[HeavyChevy95]

airleak.......

 

[waynesmobile]

Any ideas where to look for an air leak? When I hooked a test gauge up it held good fuel pressure at idle and all driving conditions.

Thank you.

Wayne

 

[HeavyChevy95]

If your 100% positive the fuel pump is functioning at 100%, I'd start looking between the lift pump and fuel tank. That portion of the fuel supply system is always under vacuum. NEVER ASSUME that just because no obvious fuel leaks are present that an airleak doesn't exist. Often enough, an inop/faulty LP will expose airleak(s) that would otherwise go unnoticed. Trust me, it doesn't take much air to cause the ECM/PCM to start freaking out....
How old are the rubber fuel lines? Like tires, fuel hoses deteriorate too and should be inspected annually and replaced at least once a decade...
Has the fuel manager been overhauled within the last decade, several possible sources for an air leak there...

 

[sathackr]

Any ideas where to look for an air leak? When I hooked a test gauge up it held good fuel pressure at idle and all driving conditions.

Thank you.

Wayne

I'll second the air theory...I had the "hard jerks" (known as fishbites) a couple of times. One was a loose fuel line on the IP inlet...check to make sure the clamp on it is tight and has a good seal.

Also I just replaced my IP last weekend and started getting fishbites again. Apparently the newer/rebuilt IPs are designed to not need the short filter harness that my old pump had on it. I removed that and the fishbites went away.

 

[waynesmobile]

I removed the short filter harness and pluged the truck harness directly into the optical sensor and the truck runs great!
Do I need to replace the filter harness or just leave it out?

Thanks for all the great ideas!

Wayne

 

[sathackr]

I removed the short filter harness and pluged the truck harness directly into the optical sensor and the truck runs great!
Do I need to replace the filter harness or just leave it out?

Thanks for all the great ideas!

Wayne

If it works...leave it out. From what I understand it's to prevent RF interference from the pump and the newer ones are designed not to need the filter.

 

[waynesmobile]

Thought I would update this thread, the truck ran great for about 75 miles and sterted doing the same fishbite/dying thing. Seting the same codes plus a code that said low voltage to fuel pump, check the alt and it was charging great at highway speed but not at low speed. Replaced the alt and that code went away. Still had fishbite/dying, replaced the PCM and the truck has run fine for 3 months now so I hope it is fixed.

Thank you for all the help.

Wayne