I have a 1997 2500 4x4 6.5L turbo deisel. Stalling periodically, sometimes right after I start it, sometimes after a little driving, at all different speeds. When it stalls it just like I turned the engine off. Always starts right back up with out a problem. Stalls more often after I put Diesel in. Replaced the PMD and relocated it on a cooler. Changed the fuel filter, put a new fuel cap on, two new batteries, just put a new vacuum pump in yesturday, after it spit out the code to replace it. Was running fine until I went that evening to put diesel in and it started stalling again and still stalling today. Any suggestions on what it could be other than the Injector Pump, trying to rule everything else out seeing it is not saying any codes. Replaced the injector pump a few years ago by GM dealer (of course not still under warranty) but that time it was a different stall then this one. ANY IDEAS WILL BE APPRECIATED.


0. Describe in detail the problem you are having. Please be as descriptive as possible.
1. Does the engine crank, or 'turn over'? YES
1a. Does the engine start and run? Yes sometimes stalls right away and then starts again right away.
1a1. If the engine does not start - Crack injector line: do you have fuel? Yes/No N/A
1b. Do you have a Wait To Start Light & the amount of time (seconds) lit. YES
1c. Ambient Condition (temperature outside indicate F or C) _____ ° Does not matter temp been in cold climate and hot climate makes nmo difference.
1d. Engine Cranking speed (if you have an accurate tachometer).
1e. Are you experiencing stalling? Yes
1f. If Stalling, describe (upon startup only, down the road, hit a bump etc) Random but more often after refueling
1g. If Stalling, do you notice loss of dash or instruments?
-note if experiencing stalling,you must indicate PMD location in #24. No just turns off

1h. Check turbo inlet and air filter for obstructions. Cone filters have lost disk and stopped air to turbo. checked and clear
1i. In a no-hot start, pour a bottle of room-temp water on the injection pump. Does it start now? yes/no N/A
1.1 Lift pump test - describe results
2. Service Engine Light while running?- on/off/intermittent OFF
2a. Service Engine light does glow during start/cranking/bulb check: Yes/No Yes
3. Model year 1997 GMC 2500HD 4x4 PU sierra 6.5L turbo diesel
3a. Odometer reading (indicate if in miles or km) almost 400Km
3b. Miles on major engine components if been replaced (example Injection pump) few years ago not sure how many KM
3c. Indicate the model number on the Injection pump (starts DS4 or DB2......)
4. Have you scanned for engine codes? (varies by pre/post 96) yes/no Yes only put out about vacuum pump replaced that.
5. List exact results on engine codes:
6. Air Filter condition (visual check) Good
7. Fuel filter condition (freshly changed/condition unknown/mileage since changed) Changed a month ago
8. Condition of Battery terminal connections (removed, cleaned and tightened) clean and tight
8a. Known condition and age of the batteries. month ago
8b. Are batteries of differing age or are they a matched set? matching
8c. Condition of Major Grounds. (same drill as batt - removed, cleaned, retightened)
9. Upon cold start, does the radiator hose get hard quickly? Yes/no
10. Upon cold start, do you have excessive white smoke? Yes/no
11. Do you have excessive cranking time before the engine starts? no[/U]
12. Have you used the block heater, and does this effect engine starting?(only try for starting problems)don't have to use it not cold enough
13. During hard acceleration, do you have excessive black smoke? Yes/no no
14. Do you have any unusual exhaust smoke issues? no
15. Turbo check out - pass/fail
16. Do you have an EGR on the engine? (An F or an S engine code 8th VIN digit)F
17. Indicate if you know if it’s a 1500, 2500, 2500HD, 3500, 3500HD.2500HD
18. Indicate fuel that you are using: Bio-diesel, #2 Diesel, #1Diesel, SVO/WVO, other Diesel
18a. If running a VO (Veggie Oil fuel) setup, indicate details of your conversion (homemade, or packaged system)
19. Are you using any fuel additives? If so, please list. yes stanadyne lubricity formula
20. Please indicate geographic region you are in: (example: Texas or Canada) Canada but in california right now
21. Do you have any service history available that might pertain to the problem you are having?
22. Please indicate any modifications to the vehicle that might help us diagnose better.
23. Upon unscrewing the fuel cap, do you have a large vacuum formed in the tank? yes/no yes
24. Location of PMD/FSD? On the pump/remoted over intake/remoted out of engine bay (please specify placement specifically) on a cooler on top of engine with no cover on it
24a. If remote mounted, describe wiring harness (homemade or purchased from a vendor?) purchased from vendor they relocated it
24b. Indicate the location and condition of the FSD/IP grounding wire.
25. Are ALL glow plugs in proper working order as per this thread? yes

fuel pressure ok? could be a lift pump located in the drivers side frame rail.first fill out a checklist (in my sig line) then read FAQs for some good info on 6.5 health and fill out a sig(also in my sig!)


And welcome to the Place!

Go through the truck, and check ALL grounds, take em off, clean em up, and reinstall them.

Stalling/eletrical issues are always a PITA, and grounds is a good place to start.

Have you looked at the OPS? Is it good? Is it the original?

Try going to the Diagonistic checklist sticky on the main 6.5 forum page and fill it out and post it up, it'll help us better, and avoid making random guesses.

Welcome to the crew :D

Before I forget, fill out your signature too, that helps us ask less questions about the truck, and more about the issue.

When you do the checklist, pay attention to the fuel cap removal part to see if you have vacuum in the tank. Since you said it stalls after you fuel up, a bad fuel cap could cause possibly cause it.

In the post it says the fuel cap was replaced.

"23. Upon unscrewing the fuel cap, do you have a large vacuum formed in the tank? yes/no yes"

So even with a NEW fuel cap you still have a large amount of Vacuum?

In the post it says the fuel cap was replaced.

Yeah, I saw that, but I've read some older posts where the dealer/parts store supplied the wrong cap, so I thought it was worth mentioning.

Have not changed oil pressure switch yet could this really cause the stalling?
Go through the truck, and check ALL grounds, take em off, clean em up, and reinstall them.

Stalling/eletrical issues are always a PITA, and grounds is a good place to start.

Have you looked at the OPS? Is it good? Is it the original?

Try going to the Diagonistic checklist sticky on the main 6.5 forum page and fill it out and post it up, it'll help us better, and avoid making random guesses.

Welcome to the crew :D

Before I forget, fill out your signature too, that helps us ask less questions about the truck, and more about the issue.

Same as it was with the last cap and it makes a decent hiss as i open it.In the post it says the fuel cap was replaced.

"23. Upon unscrewing the fuel cap, do you have a large vacuum formed in the tank? yes/no yes"

So even with a NEW fuel cap you still have a large amount of Vacuum?

I would say its the fuel cap. If not its a good start. There should be no vaccum when you remove the fuel cap. Get a new one pronto

Yeah, I saw that, but I've read some older posts where the dealer/parts store supplied the wrong cap, so I thought it was worth mentioning.

That's what I started thinking when I saw there was still a large amount of vac when opening the cap.

OPS and LP work hand in hand, so if the OPS goes, you can get LP issues.

I'd test to see how much fuel pressure you have, and also double check that fuel cap to make sure it's right.

How is the condition of the harness for your FSD?

Gas cap and visual check of the harness is the easiest to check, but I'd look at the gas cap first...

Vacuum, stalling after fuel up... Sounds like the cap so far...

By the way, where is the FSD relocated to?

If you still have the old fuel cap, you can drill a hole through the center & put it back on (or you could leave the cap off). If it doesn't stall anymore, you'll know it's the cap.

The lift pump draws power through the oil pressure switch. If it's bad, the LP won't run.
Do the LP test -see here: http://www.dieselplace.com/forum/showthread.php?t=39350

but I put a new one on yesturday and yes it is the proper one for it am i not supose to have any noise when i take off the cap

is the lp the same as the injector pump or is that two different things

on top of the engine it is where the shop in BC canada located it to

was still stalling right after they put a new one on and relocated it

What exactally are you considering a "decent hiss" Because even the correct cap will still make a hissing noise when it is first opened. But it is only for about a second or 2

ok i am going to drive it around with no fuel cap and see if that does it and change the ops.

it makes a hiss for aout a second or two

where is the ops located and is it easy to change?

1 psi or 2" of vacuum is acceptable. when the tank is empty it will make a bigger noise than when it is half full.a second or 2 probly wont hurt but try it without the cap on to eliminate it as an issue.

The lp or LP or lift pump is not the same as the injector pump. the LP is an electric fuel pump mounted in the frame rail that supplies fuel to the IP.http://www.dieselplace.com/forum/showthread.php?t=39350 read this and do the test to eliminate the lift pump as an issue.

Mounting the FSD on the manifold isn't the best location for it.
Heath Diesel puts theirs behind/under the bumper.

LP stands for Lift Pump, it draws fuel from the tank, and supplys the Injection Pump with fuel.

2 different things, but a bad/non working LP can take out an IP.

I'd check your fuel pressure and go for a drive, and watch the gauge, if you lose fuel pressure and it stalls, then it can be a LP/OPS issue, if it stalls without loosing pressure, it could be something else.

I hate seeing people spend money only to still have the problem.

where is the ops located and is it easy to change?

It's located towards the rear of the engine, in the vee, it's black and almost the size of a BIC lighter, if not slightly larger.

http://www.dieselplace.com/forum/attachment.php?attachmentid=8736&d=1126898315

Lift pump not issue lots of fuel coming out when did test.

Lift pump not issue lots of fuel coming out when did test.

How long ago was the FSD replaced and mounted to the manifold?

stalls with out loosing pressure watch my guages all the time.

was still stalling right after the put the new pmd in then they put another new pmd in to rule that out still stalled.

So if the LP is working should I replace the OPS? It looks like the one from the factory I don't think it has ever been changed.

stalls with out loosing pressure watch my guages all the time.
you have a fuel pressure gauge?

Did you clean all the grounds per the FAQ's? Good grounds are the VERY important to a 6.5.

other than that I wonder about "snot on the stocking"? seems the problem comes whenever refuelled, crap in the tank maybe? taking stabs in the dark here?

Grounds on the batteries are good but have not done others, are there certain ones I should be looking for. My brother normally does this for me but unfortunately I am in California and can not stand getting ripped off by the dealerships anymore. So any advice or discription is appreciated. I do know how to work on my truck just need some discription and I will do what ever is needed. How do you check snot on the sock and how do I get at it?

i ment the oil pressure guage not fuel. I watch my guages an the oil pressure always stays the same before it stalls.

It would, oil pump is mechanically driven off the crank.

I ment fuel pressure. If you lose fuel pressure then stall, it could be either the LP or OPS.

You'd have to get a fuel gauge, and plumb it inline between the lift pump and injection pump.

Go to the Referance Material & FAQ sticky, and look through it, the second post has everything in alphabetical order, look for Snot in the sock, OPS, LP, any and everything, the more you know, the better off you are.

Do you fill up at the no name diesel pumps or the big ones? Shell, Petro Can, Esso, etc etc

Low grade diesel can plug a fuel filter in no time, causing stalling too.

I'm just trying to think of anything that can cause stalling, sadly, on the 6.5 it could be a fuel, eletrical, componant or mechanical issue... Lots to cover.

http://www.dieselplace.com/forum/showthread.php?t=181489&highlight=snot+stockings
fuel strainer sock is in the fuel tank at the end of the draw tube. crap in the tank aka."snot" can restrict fuel flow. Don't know if this is your issue, but I am runnin outta ideas.

look in the FAQ for pictures of ground locations. Good write up in there.

You never answered how old the PMD is?

The pmd is a month old and was still stalling right after they put it in so they put a new one in again just to rule out a faulty new one. Still stalling after the second new one.

Check the ground wire on the pmd harness too. It needs to be grounded to the IP.

Ok so I took the fuel cap off my truck and have driven it all day and last night. NO STALLING so far...YAY!!! MAye this is it cross your fingers for me... I have ordered a new one from GM. Thank you everyone for your help let you know if I have more problems.