[phalfhide]

My truck start good and it will run fine then all of a sudden it will shut off I will try to start it and it wont start then in about 2 minuts it will start up and run fine for the rest of the day ,starting and running fine.
It only happens once in a while I put a new furl filter thinking it is not getting fuel
What do you all think?

 

[edzzed]

pmd and or lift pump ??? but first do the diagnostic checklist and post the results. Ed

 

[phalfhide]

. 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
1a1. If the engine does not start - Crack injector line: do you have fuel? Yes/No
1b. Do you have a Wait To Start Light & the amount of time (seconds) lit.
1c. Ambient Condition (temperature outside indicate F or C) _____ °
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) Down the road
1g. If Stalling, do you notice loss of dash or instruments?
-note if experiencing stalling,you must indicate PMD location in #24.

1h. Check turbo inlet and air filter for obstructions. Cone filters have lost disk and stopped air to turbo.
1.1 Lift pump test - describe results open t valv while engine is running and furl runs out​

2. Service Engine Light while running?- on/off/intermittent no light come on
2a. Service Engine light does glow during start/cranking/bulb check: Yes/No Yes
3. Model year 96 gmc suburban
3a. Odometer reading (indicate if in miles or km)185000 Miles new IP at 95000
3b. Miles on major engine components if been replaced (example Injection pump)
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
5. List exact results on engine codes:
6. Air Filter condition (visual check) new
7. Fuel filter condition (freshly changed/condition unknown/mileage since changed) I put a new on in 2 days ago
8. Condition of Battery terminal connections (removed, cleaned and tightened) tightened
8a. Known condition and age of the batteries.4 months old
8b. Are batteries of differing age or are they a matched set? matching set
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?
12. Have you used the block heater, and does this effect engine starting?(only try for starting problems)
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.
18. Indicate fuel that you are using: Bio-diesel, #2 Diesel, #1Diesel, SVO/WVO, other
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. Lucas injector cleaner
20. Please indicate geographic region you are in: (example: Texas or Canada) N Carolina
21. Do you have any service history available that might pertain to the problem you are having? No
22. Please indicate any modifications to the vehicle that might help us diagnose better. see sig
23. Upon unscrewing the fuel cap, do you have a large vacuum formed in the tank? yes/no
24. Location of PMD/FSD? On the pump/remoted over intake/remoted out of engine bay (please specify placement specifically) Under front bumper (used)
24a. If remote mounted, describe wiring harness (homemade or purchased from a vendor?)Purchased
24b. Indicate the location and condition of the FSD/IP grounding wire. locared on Ip
25. Are ALL glow plugs in proper working order as per this thread? Yes

 

[chickenhunterbob]

I think...

That maybe, just maybe, that "good used" PMD you bought a couple months ago, should be the prime suspect in your investigation.

At the time, you mentioned the PMD on the pump was good, and you were going to leave it there, for a spare.

If I were you, I'd plug the regular harness back into the PMD on the pump, and go from there, because now it seems you're in need...of a spare

 

[phalfhide]

I also have one in my glove box, I will change the PMD and see what happens I think I am going to put a new OPS also.
Where is the ops and is it hard to change

 

[HamOP]

You skipped 2, either one of which may point to your problem.

1g. If Stalling, do you notice loss of dash or instruments?

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

Since it starts and runs but croaks off occasionally #23 is probably OK. If you loose the dash though it could be a ground problem or your ignition switch. Give those two a look see again.

The FSD (not a PMD anymore) is in a great location in the front bumper -- Is it mounted to a heat sink?

 

[phalfhide]

You skipped 2, either one of which may point to your problem.

1g. If Stalling, do you notice loss of dash or instruments?

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

Since it starts and runs but croaks off occasionally #23 is probably OK. If you loose the dash though it could be a ground problem or your ignition switch. Give those two a look see again.

The FSD (not a PMD anymore) is in a great location in the front bumper -- Is it mounted to a heat sink?

Yes my "FSD" is on a sink
when it shuts off my lights on the dash come on Like if i turn the ignition on before I start

 

[JMJNet]

Check the extension cable, make sure there is no rub that can cause some chaffing.

Also check your ground, may be something loose.

 

[phalfhide]

Check the extension cable, make sure there is no rub that can cause some chaffing.

Also check your ground, may be something loose.

where are the grounds I know 2 going to the engine which i cleaned is there more?

 

[Schwind]

look at the picks in my garage. there is also one on the firewall under the A/C evaporator and on on the frame rail at the upper A-arm passengers side.

 

[phalfhide]

where is the OPS i cant find it?

 

[JMJNet]

OPS on a 96+ is under the intake manifold on the engine valley.

It is a little bit more difficult to access.

My suggestion is to also get a relay like the one Schwind suggested while you changed it so you don't have to change the OPS again.

Oh, if I have not mentioned, get an ACDelco one.

 

[phalfhide]

OPS on a 96+ is under the intake manifold on the engine valley.

It is a little bit more difficult to access.

My suggestion is to also get a relay like the one Schwind suggested while you changed it so you don't have to change the OPS again.

Oh, if I have not mentioned, get an ACDelco one.

What does the relay do ?Is it something I have to wire up?

 

[phalfhide]

I put my backup on ,so far so good Lets see what happens

 

[phalfhide]

Up date

5 days with new PMD/FSD no problem
T just wanted to give a heads up
p.S. I think it it a good idea to have a backup PMD in your glove box like I did you just don't know when it will act up and with a remote on my bumper I could hook up my back up and zip tie it till I get home.
HAVE FUN