Diesel Place banner
1 - 20 of 22 Posts

·
Registered
Joined
·
10 Posts
Discussion Starter · #1 ·
So this is really picking me. It's my sons truck and we have been through it from end to end. I am just looking for suggestions for something I have missed. The truck has had intermittent stalling issues for a while now. Some days it starts and runs like a champ, and other days (more frequent now) it starts, runs for ten minutes and stalls, and then will not run again. It will catch and immediately stall. If we keep trying it will magically run and cause no issues the rest of the day.
We bought the truck this summer cheap with two codes. Optic sensor and stepper motor. We replaced the optic sensor a while ago and the code is gone. It ran fine with and without that code. We also had a stepper motor code. Replaced that and the code did not go away. I pulled the pump and found the piston was actually stuck. (the truck sat for a while before we bought it.) I tapped it and it freed up. I pulled the covers and lubed the heck out of it and it moved easily. Put it all back together and no more stepper motor code. There was a chisel mark to time the pump and I made very sure to put it back in the same spot, but rotating it one to 2 mm either way makes no difference to the stalling anyway. So it runs great when it runs but this stalling thing is a head scratcher. I thought it was air in the fuel but now I am not so sure. To eliminate air leaks and fuel issues I have: dropped the tank. Clean as a whistle and clean sock. New lift pump. Added wires to bypass the FSS and it is verified to work fine and has 7 psi at the pump. Lots of flow at the tee. New fuel filter. replaced all fuel lines. Not a drop of fuel leaking or any wetness anywhere including under the pump. Valley is dry. When I crack the drivers side injectors I have fuel at all four. No bubbles in the fuel. Makes no difference if the fuel cap is on or off. (minor vacuum after running for a while) Along the way we have tried two known good PMD's (one new) with no difference. And when it is not stalling it runs fine on both of them. PMD is on a heat sink out of the valley. When it is stalling and not wanting to start it it makes no difference whether the optic eye is plugged in or not. I have checked every single electrical connection and I have cleaned all the grounds and also added a big heavy new one frame to motor. Truck has 280,000 km on it. What have I missed? Thanks in advance for any suggestions.
 

·
Registered
Joined
·
10 Posts
Discussion Starter · #3 ·
Also, glow plugs all verified working well. I can go out at minus 15 and one glow plug cycle will start it....if it feels like it. But it will run for ten minutes and then shut off and then its 30 minutes of crank-catch-stall crank-catch-stall and eventually it will go.
 

·
Administrator
Joined
·
21,805 Posts
Welcome

Please tell us more about the vehicle ( Year, Make, Model ) and list all mods
(y)
 

·
Registered
Joined
·
10 Posts
Discussion Starter · #5 ·
1. Describe the problem you are having in detail:

2. Year of truck/engine. 1995 2500 4x4
3. Odometer reading (indicate miles or kilometers). 280,000 km
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. 2500
6. Do you have an EGR on the engine? (An F or an S engine code 8th VIN digit) no
7. Air Filter condition (visual check). new
8. Fuel filter condition (freshly changed, mileage since changed). new
9. Location of PMD/FSD? (ex. on pump/remote over intake, behind bumper).over intake.
9a. If remote mounted, describe wiring harness (homemade or purchased from which vendor). ebay. no difference with or without
9b. Indicate the location and condition of the FSD/IP grounding wire. all grounds good. this one is as factory
10. Outside Temperature (C or F). _ ° not temp dependent

11. Service Engine Light while running?- on/off/intermittent no codes
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. none

13. Condition of Battery terminals (removed, cleaned and tightened). good
14. Known condition and age of Batteries. near new
14a. Are batteries a matched set of same age? yes
15. Condition of Major Grounds (removed, cleaned and tightened) all good
15a Have the batteries been individually load tested? yes. cranks great

16. Does engine crank, or "turn over"? yes
16a. Does engine start and run? sometimes
17. If engine does not start- Crack injector line: do you have fuel? Yes/No yes
18. Does your Wait To Start light come on? yes
18a.Number of seconds WTS light is lit. not sure. 5 sec maybe
19. Engine Cranking speed (if you have an accurate tachometer). don't know. fast

20. Are you experiencing Stalling? yes
20a. Describe the event (upon startup only, down the road, hit a bump, etc...) as described above
20b. Do you notice loss of dash or instruments? no they all work
21. Check turbo inlet and air filter for obstructions. all good
22. In a no-hot start, pour a bottle of room-temp water on the injection pump. Does it start now? not a hot start issue
23. Lift pump test - Describe results. 7 psi good flow

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 sometimes
27. Have you used the block heater? Does it affect engine starting? (only try for starting problems). yes. works fine
28. Are all glow plugs in proper working order? yes

29. During hard acceleration, do you have excessive black smoke? Yes/No no, pulls great
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 pump 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. none
34. Upon unscrewing fuel cap, do you have a large vacuum formed in the tank? Yes/No a bit
35. Do you have any service history available that might pertain to the problem you are having? as described
36. Please indicate any modifications to the vehicle that might help us diagnose better. none. Bone stock.
 

·
Ronald Reagan fan
Joined
·
5,025 Posts
You say the pmd is on a heat sink so what kind of shape is the relocation harness in?Is it a harness that’s made up from scratch to extend the pmd out of the engine compartment or a new harness?Oh wait……I just read you have it above the intake…..you should go behind the front bumper with a 6ft harness.The pmd will never stay cool to the touch when it’s mounted there.

I’m just going to say a few words about extension harnesses.Even if a new harness is being purchased,there is some junk being sold online so if not purchased from a well known supplier you can have your share of trouble.I’ve also seen cases where the pins in the pmd wiring connector can get pushed backwards when you attempt to connect to the pmd itself.Myself personally I would buy a new stanadyne pmd harness that connects to the armature area on the back of the injection pump so you can rule that out and make sure the ground from that harness is upon the injection pump.

Also the main injection pump harness under the intake that connects to a large weather proof connector at the back of the engine is another thing you should inspect carefully.That harnes is subject to extreme heat over the years and should be replaced anyway.I bought a couple new complete harnesses here from a member that does great work and I’ve been more than happy with it.
 

·
Ronald Reagan fan
Joined
·
5,025 Posts
These are both harnesses I was referring to….
 

Attachments

·
Registered
Joined
·
10 Posts
Discussion Starter · #8 ·
The PMD harness seems to be well made and if makes no difference whether or not it is used. We get the same symptoms plugging the PMD in to the factory plug.
I looked quite carefully at the other pump harness and it seems to be in good condition. This is a West coast truck and everything is quite clean and rust free. I cleaned every ground but they were all excellent to begin with. The one exception is that there was a section of rusty fuel line for some reason, along the frame rail. But I dropped the tank and the lines going into the tank were fine. Still, for lack of ideas and much left to look at I am going to rig up a temporary fuel supply today and bypass the tank and most of the fuel line.
 

·
Administrator
Joined
·
21,805 Posts
The PMD harness seems to be well made and if makes no difference whether or not it is used. We get the same symptoms plugging the PMD in to the factory plug.
I looked quite carefully at the other pump harness and it seems to be in good condition. This is a West coast truck and everything is quite clean and rust free. I cleaned every ground but they were all excellent to begin with. The one exception is that there was a section of rusty fuel line for some reason, along the frame rail. But I dropped the tank and the lines going into the tank were fine. Still, for lack of ideas and much left to look at I am going to rig up a temporary fuel supply today and bypass the tank and most of the fuel line.
I would install a piece of clear fuel line on the return side of the IP to help locate any air in fuel issues as shown here in this link: Question: - 1999 GMC Bluebird 6.5L TD - PMD &amp...
 
  • Like
Reactions: Glagulator

·
Registered
Joined
·
10 Posts
Discussion Starter · #10 ·
If nothing else, perhaps you all can help me rule out either fuel or electrical. It is a pretty basic diesel, so to run and keep running what does it need?
Good supply of air free fuel but will run or at least idle without a lift pump.
Clean unrestricted air supply
FSS retracted to allow fuel through the pump
Isn't everything else secondary to it actually running and staying running?
 

·
Registered
Joined
·
10 Posts
Discussion Starter · #11 ·
We already had a clear return line. So this morning I ran a fuel line from my track loader through its lift pump and filter directly to the truck pump inlet. The truck cleared some air and then ran and idled fine. No bubbles at all while it was idling. Good flow from the return. I turned it off after ten minutes and straight back to the usual. Catches and dies catches and dies. But now I see very little fuel returning out of the pump. So what is there in the pump itself that could restrict or turn fuel off other than the FSS? I dont want to replace the pump but i dont know what else to check. And if its something in the pump then what is it?
 

·
Registered
95 K2500 Suburban, 6.5L
Joined
·
17 Posts
So this is really picking me. It's my sons truck and we have been through it from end to end. I am just looking for suggestions for something I have missed. The truck has had intermittent stalling issues for a while now. Some days it starts and runs like a champ, and other days (more frequent now) it starts, runs for ten minutes and stalls, and then will not run again. It will catch and immediately stall. If we keep trying it will magically run and cause no issues the rest of the day.
We bought the truck this summer cheap with two codes. Optic sensor and stepper motor. We replaced the optic sensor a while ago and the code is gone. It ran fine with and without that code. We also had a stepper motor code. Replaced that and the code did not go away. I pulled the pump and found the piston was actually stuck. (the truck sat for a while before we bought it.) I tapped it and it freed up. I pulled the covers and lubed the heck out of it and it moved easily. Put it all back together and no more stepper motor code. There was a chisel mark to time the pump and I made very sure to put it back in the same spot, but rotating it one to 2 mm either way makes no difference to the stalling anyway. So it runs great when it runs but this stalling thing is a head scratcher. I thought it was air in the fuel but now I am not so sure. To eliminate air leaks and fuel issues I have: dropped the tank. Clean as a whistle and clean sock. New lift pump. Added wires to bypass the FSS and it is verified to work fine and has 7 psi at the pump. Lots of flow at the tee. New fuel filter. replaced all fuel lines. Not a drop of fuel leaking or any wetness anywhere including under the pump. Valley is dry. When I crack the drivers side injectors I have fuel at all four. No bubbles in the fuel. Makes no difference if the fuel cap is on or off. (minor vacuum after running for a while) Along the way we have tried two known good PMD's (one new) with no difference. And when it is not stalling it runs fine on both of them. PMD is on a heat sink out of the valley. When it is stalling and not wanting to start it it makes no difference whether the optic eye is plugged in or not. I have checked every single electrical connection and I have cleaned all the grounds and also added a big heavy new one frame to motor. Truck has 280,000 km on it. What have I missed? Thanks in advance for any suggestions.
How about the crank sensor? Mine was bad (and also gunked up) and never threw a code. Caused all kinds of problems.
 
  • Like
Reactions: dieselolds

·
Registered
Joined
·
42 Posts
I have had an intermittent stall or no start for some time. I found it would happen more frequently driving around a corner or reversing up a hill.

In my case, I have traced it back to some sort of wiring fault that affects the wire to the optical sensor from the ecu.

The wires from the optical sensor come together in a loom that runs to the back of the engine, and then has a T join with a major loom running over the top of the bellhousing by the firewall.
I have not yet had time to fully dissect it, but I have made a little more room and wiggling the wires can cause a running engine to stall, and getting them in the right place lets the engine run.

Mine is a RHD factory suburban though, so it could be quite different from yours, it has the hummer 6.5 with the turbo over the bell housing.
 

·
Registered
Joined
·
10 Posts
Discussion Starter · #15 ·
Thank you for the suggestions. I replaced the pump and crank sensor together and it is cured so I guess I will never know which the problem was. The crank sensor fell apart and I had to wind a drywall screw into it to get it out so maybe the wiring inside the end was bad. I suspect though it was the delivery solenoid.
 

·
Registered
Joined
·
71 Posts
Thank you for the suggestions. I replaced the pump and crank sensor together and it is cured so I guess I will never know which the problem was. The crank sensor fell apart and I had to wind a drywall screw into it to get it out so maybe the wiring inside the end was bad. I suspect though it was the delivery solenoid.
What was involved with replacing both the crank sensor and delivery solenoid? Did you use AC Delco for both?
 

·
Registered
Joined
·
10 Posts
Discussion Starter · #17 ·
The delivery solenoid is in the bottom of the pump. I made no attempt to touch that. I just replaced the whole pump. I got a pump from pensacola diesel because it was cheap. It did fix the problem but I am not real excited about the "rebuild" they did. I am not saying its a bad pump, but.... Not really rebuilt either. It was the cheapest one on ebay for a reason. I made a video of what I noticed if you want to look.


Again, not saying its a bad pump, but I dont expect a long trouble free life from it either.

The crank sensor falls apart when you touch it. Not fun. After the fact I see it is a common issue and there is lots of info online.
 

·
Administrator
Joined
·
21,805 Posts
The delivery solenoid is in the bottom of the pump. I made no attempt to touch that. I just replaced the whole pump. I got a pump from pensacola diesel because it was cheap. It did fix the problem but I am not real excited about the "rebuild" they did. I am not saying its a bad pump, but.... Not really rebuilt either. It was the cheapest one on ebay for a reason. I made a video of what I noticed if you want to look.


Again, not saying its a bad pump, but I dont expect a long trouble free life from it either.

The crank sensor falls apart when you touch it. Not fun. After the fact I see it is a common issue and there is lots of info online.
Lots of Customer no-service complaints and parts quality issues with Pensacola. Just Google their reviews
 
  • Like
Reactions: dieselolds

·
Ronald Reagan fan
Joined
·
5,025 Posts
The delivery solenoid is in the bottom of the pump. I made no attempt to touch that. I just replaced the whole pump. I got a pump from pensacola diesel because it was cheap. It did fix the problem but I am not real excited about the "rebuild" they did. I am not saying its a bad pump, but.... Not really rebuilt either. It was the cheapest one on ebay for a reason. I made a video of what I noticed if you want to look.


Again, not saying its a bad pump, but I dont expect a long trouble free life from it either.

The crank sensor falls apart when you touch it. Not fun. After the fact I see it is a common issue and there is lots of info online.
I’ve only had one experience with Pensacola diesel.I mentioned this maybe a couple weeks ago in these threads but the 94 truck I worked on for a guy I knew at the time had a Pensacola reman pump installed on it by me and the experience dealing with them was a good one and never had a issue with that pump after that so that was at least 15 yrs ago.No issues since then that I know of.
 
1 - 20 of 22 Posts
Top