the never ending problem

[hate my 6.5]

hi guys
i have been fighting this for a long time :mad2: hope some one can help

i have a 94 6.5 that will just shut off like the key was turned the codes at the time where 17,18,35,36
i was told it had to be the PMD, replaced it and moved it to the bumper still had the trouble!!!
talked to a different shop they said it was the IP replace that then the trans went out (whole different story)
now the truck is back up and running (kinda)
i am still having the same problem!! i have a hard time beliveing that the IP/PMD are bad with less than 1500 miles on them.

any ideas?

 

[great white]

hi guys
i have been fighting this for a long time :mad2: hope some one can help

i have a 94 6.5 that will just shut off like the key was turned the codes at the time where 17,18,35,36
i was told it had to be the PMD, replaced it and moved it to the bumper still had the trouble!!!
talked to a different shop they said it was the IP replace that then the trans went out (whole different story)
now the truck is back up and running (kinda)
i am still having the same problem!! i have a hard time beliveing that the IP/PMD are bad with less than 1500 miles on them.

any ideas?

Sudden stoppages such as your description usually indicate an electrical fault.

Pmd is a suspect, but you've replaced that.

Another common item that can cause this type of behavior is the igniton switch/tumbler assembly.

Unfortunately, this is an expensive item to replace on speculation.

Once the truck is running, try grasping the key cylinder and see if it has play in any direction. If it does and the truck dies, you have a very probable culprit....

 

[Dieseldad97]

Hahaha. Welcome here. I just saw your username hahahahahaha.

Did you replace your PMD with a brand new one, or used but good one?

 

[bk95td]

With a 94 it is less likely to be the ignition switch but it is possible.
I'd start with cleaning every ground connection. The ones on the rear of the intake and engine to firewall are very important. Check all fuse connections and fuses. These things are free and should be done to eliminate them as possibilities.
Another possibility is the Filter harness if it has one yet. It is a short harness with a rectangular black piece of plastic that is attached to the connector on the top of the IP. The short harness can be removed and run the engine with plugged in direct.
Try this FREE stuff and see what happens.
Next step is to check wiring connectors for loose or pushed out pins.[free also]
And:welcome5::welcome5:

 

[JiFaire]

Welcome here!

Please take the time to fill out the following checklist to let us 'hear and see' your truck... also let us know if you have received/tried any other advice you've gotten from other forums, so we don't duplicate stuff that obviously hasn't worked so far.

We would rather gather data and help you DIAGNOSE your problem than toss out a gazillion random ideas for you to try. Repairing engines by replacing parts can be an expensive game...

Problem: Explain your problem in concise language (ie: Cranks but won’t fire). ____________________________

Demographics: tell us about your truck and your ambient conditions:

- Year: ______
- Truck model and class (ie: c2500) _________
- Automatic or Standard __________
- Mileage: (indicate miles or km) _________
- Replaced parts and mods (IP, PMD, chip/PCM, TM, injectors etc) ___________
- Model: ‘S’ or ‘F’ engine, NA or Turbo, EGR? ______________
- Ambient outside temp: (indicate *C or *F) __________
- What fuel are you using? (#1 Diesel, #2 Diesel, Bio, VO, WVO, etc) _________
- What fuel additives are you using? ___________
- Where are you located? _____________

General maintenance: inspect and evaluate the condition of each. When were they last changed?
- Air filter _________
- Fuel filter _________
- CDR Valve? _________
- Coolant – last flushed/replaced at _____________
- Oil – synthetic/regular, changed at ___________
- Batteries – state of charge, (matched set) replaced at _____________
- Battery cables and grounds (removed, cleaned and tightened): ______________
- Glow Plugs - how many miles on them? _________ What type? _____________
- Injectors - last changed at _______________


History: (Describe how the problem first appeared.)
- What were you doing when it happened? ______________
- How was the truck running fine before this problem appeared? _____________
- Has this problem ever happened before? _______________________
- Describe any related factors that might be part of the problem. ______________
- Have you checked for DTC (Diagnostic Trouble Codes)? (Y.N) ____ And? ________

[FONT=&quot]
[/FONT] Diagnostics:

1] Starting:
1a] Does the engine start? _________
1b] Does the engine crank over? ________
1c] Are your batteries fully charged? _________
1d] Have you removed, cleaned, and tightened all battery connections? ________
1e] Does your Wait to Start light come on for a time? How long? _________
1f] Does your glow plug light come on? _________ For how long? _________
1g] Do you see smoke from the exhaust while cranking? What color? ________
1h] Does the Service Engine Light Glow during Start/bulb check? ________

2] Fuel Issues (if not running):
2a] Can you hear your lift pump working? ____________
2b] Do you get a steady flow of fuel from the water drain (T-handle) ? _________
2c] Loosen the inlet line from the IP – is fuel coming out (Lift Pump on)? ___________
2d] Loosen an injector line and crank the engine - does fuel come out? _________
2e] Do you hear a vacuum (hiss) when you remove the fuel cap? ___________

3] PMD / IP Issues
3a] Location of PMD (on pump, on intake, remote mounted) ___________
3b] Condition of Extension harness (if used) Vendor or Homemade? _________
3c] Condition of grounds / ground wires to IP / PMD. Check Harness. _________
3d] PMD Make: ___________
3e] PMD Age: _____________

4] Stalling Issues
4a] Do you experience stalling only when hot? ____________
4b] Does it stall under particular circumstances? (ie hit bump, or on accel) ______
4c] Does pouring cool water over the IP seem to help with restarting? _________
4d] Is stalling momentary (engine recovers)? _________
4e] Does SES light come on when engine hiccups? _________
4f] Does cruise control quit working when engine hiccups? ___________
4g] Does re-starting seem to reset engine, restoring cruise and power? _________
4h] Changes to dash lights or instruments during stalling events? ___________

5] Running Issues
5a] On cold start, does upper rad hose get hard before engine warms up? _______
5b] Any bubbles or oil film in coolant overflow tank? _______
5c] Any white slime on oil surfaces (dipstick, CDR, oil Fill cap)? __________
5d] Excessive white smoke from exhaust on cold start? _________
5e] Excessive black smoke from exhaust under hard acceleration? __________

6] Performance Issues
6a] Do you have gauges (boost, EGT) ? ___________
6b] Maximum boost under load? ____________
6c] Have you added a performance PCM (reflash) or Chip? ______________
6d] Have you changed exhaust / downpipe / crossover? ________________
6e] Wastegate – mechanical or vacuum (OEM)? ______________

7] Temperature-related Issues:
7a] Single or dual thermostats? ____________
7b] Have you replaced them lately? Manufacturer of replacements? _________
7c] Have you pulled and cleaned Radiator and coolers lately? ____________
7d] Have you replaced the fan clutch? Manufacturer of replacement? ________
7e] (winter) Have you tested your antifreeze? Good to what temp? __________
7f] (winter) Are you using a winter grille cover? ___________

List and describe any other factors which are not addressed in this checklist. We can’t see, hear, smell, or touch your truck, so the more descriptive information you can give, the more likely it is that somebody can assist you.

_________________________________

 

[3500GMC]

Cheer up, it get's worse. :rof:

 

[buddy]

Are you saying that you had these issues and then to resolve them you replaced the PMD and the IP? And the same problem is still happening, which is stalling.

And you really have to better define the stalling, because if you turn off the key you lose all the lights and radio and stuff, or do you just mean it stalls all of a sudden?

What fuel or additives are you putting in the truck?

So were the codes 17, 18, 35 and 36 with the old or new IP? Where did the new IP come from?

You must realize most shops have no idea how to troubleshoot stuff anymore, least of which this vehicle. So dont think its something really weird just because they are clueless.

Like said earlier, it sounds like a poor ground wire on the back of the passenger side head. There should be a couple ground wires attached to the back intake bolts and a coolant blockoff plate stud.

That wouldnt cause those codes though, the codes are IP codes, and removeing the Optical Sensor filter may help. That is covered on the first page of this writeup of common maintenance items. Although stalling and these codes can also be caused by air in the fuel, so if you dont know how to test your fuel pressure from the fuel tank it would be a good time to learn. Also, check the fuel lines right above the fuel tank, even with good fuel pressure it could be sucking air into rotten fuel lines and causing stalling.

 

[WarWagon]

Cheer up, it get's worse. :rof:

:thumbsup: And this fellow is an optimist!

 

[Burning oil]

Like a few have said, check the ground specialy the rear pass intake stud. If you replaced the IP and it fixed the problem for awhile its probaly because in the process they had to remove and reinstall the grounds on that stud causing them to temp make contact again. Those grounds have to be perfect, so whatever it takes get them right.
It will cause the truck to shut off like you turned the key off.

I love to hate my 6.5 too.

 

[orrum]

Yee Haw!!!!! :hello: Grounds, grounds, grounds, gotta check them grounds, its all about them grounds!!!!! :agreed: Its all this newbie is qualified to do but boy am I good at it, got bare @ssed copper all over my engine, for every ground I found I added another one!!!! :thumbsup: Now if I could just get a handle on that woodchuck chuckin wood thing::::::: :mad2:

 

[DieselSlug]

Yee Haw!!!!! :hello: Grounds, grounds, grounds, gotta check them grounds, its all about them grounds!!!!! :agreed: Its all this newbie is qualified to do but boy am I good at it, got bare @ssed copper all over my engine, for every ground I found I added another one!!!! :thumbsup: Now if I could just get a handle on that woodchuck chuckin wood thing::::::: :mad2:

Dang woodchucks! Quit chuckin' my wood! LOL

There is also a small ground wire that should stay attached to the I/P. Make sure it still is.

 

[hate my 6.5]

WOW I was not expecting so many replys thanks everyone

Dieselklad the PMD was new when relocated

bk95td all the fuses are good and I have checked the grounds (I think i got them all) going to check them again

buddy just the engine stops every thing else will stay on, if my memory serves me right the last time i checked the fuel pressure it was running about 7 psi looking for my guage to recheck it, strange how tools just disapear every time you need one

diesel slug yes the ground is still on the top of the IP

now today the air temp was below 80F and it ran like a champ with no shut downs at all

 

[hate my 6.5]

Demographics: tell us about your truck and your ambient conditions:

- Year: ____1994__
- Truck model and class (ie: c2500) ___3500______
- Automatic or Standard ______auto____
- Mileage: (indicate miles or km) _____161,000 miles____
- Replaced parts and mods (IP, PMD, chip/PCM, TM, injectors etc) ____IP,PMD,OPS_______
- Model: ‘S’ or ‘F’ engine, NA or Turbo, EGR? _____"F" tubro, no EGR_________
- Ambient outside temp: (indicate *C or *F) ___trouble starts about 80-85deg f _______
- What fuel are you using? (#1 Diesel, #2 Diesel, Bio, VO, WVO, etc) ___#2______
- What fuel additives are you using? ____power service_______
- Where are you located? _____MT________

General maintenance: inspect and evaluate the condition of each. When were they last changed?
- Air filter _____about 5000 mile ago____
- Fuel filter ____yes several times_____
- CDR Valve? _____HUH?____
- Coolant – last flushed/replaced at _______unknown______
- Oil – synthetic/regular, changed at ____regular 3000ish miles_______
- Batteries – state of charge, (matched set) replaced at _matched set fully charged replaced 2 years ago_______
- Battery cables and grounds (removed, cleaned and tightened): ____yes__________
- Glow Plugs - how many miles on them? ____unkown_____ What type? _____unknown________
- Injectors - last changed at _____unknown__________


History: (Describe how the problem first appeared.)
- What were you doing when it happened? ___driving about 30 MPH___________
- How was the truck running fine before this problem appeared? _____running good________
- Has this problem ever happened before? _________no______________
- Describe any related factors that might be part of the problem. ______________
- Have you checked for DTC (Diagnostic Trouble Codes)? (Y.N) __Y__ And? ____17,18,35,36____


Diagnostics:

1] Starting:
1a] Does the engine start? _____yes____
1b] Does the engine crank over? ____yes____
1c] Are your batteries fully charged? ____yes_____
1d] Have you removed, cleaned, and tightened all battery connections? ____yes____
1e] Does your Wait to Start light come on for a time? How long? _________
1f] Does your glow plug light come on? _____yes____ For how long? __15-20 sec_______
1g] Do you see smoke from the exhaust while cranking? What color? ___no_____
1h] Does the Service Engine Light Glow during Start/bulb check? ___yes_____

2] Fuel Issues (if not running):
2a] Can you hear your lift pump working? ____yes________
2b] Do you get a steady flow of fuel from the water drain (T-handle) ? _____yes____
2c] Loosen the inlet line from the IP – is fuel coming out (Lift Pump on)? ___yes________
2d] Loosen an injector line and crank the engine - does fuel come out? _________
2e] Do you hear a vacuum (hiss) when you remove the fuel cap? _______yes____

3] PMD / IP Issues
3a] Location of PMD (on pump, on intake, remote mounted) _____behind bumper______
3b] Condition of Extension harness (if used) Vendor or Homemade? ___new vendor______
3c] Condition of grounds / ground wires to IP / PMD. Check Harness. _____good____
3d] PMD Make: ____stanadyne_______
3e] PMD Age: ______1000 miles_______

4] Stalling Issues
4a] Do you experience stalling only when hot? _____yes_______
4b] Does it stall under particular circumstances? (ie hit bump, or on accel) ____anytime__
4c] Does pouring cool water over the IP seem to help with restarting? ____no_____
4d] Is stalling momentary (engine recovers)? _____no____
4e] Does SES light come on when engine hiccups? ___sometimes______
4f] Does cruise control quit working when engine hiccups? ___yes________
4g] Does re-starting seem to reset engine, restoring cruise and power? ____yes_____
4h] Changes to dash lights or instruments during stalling events? _____no______

5] Running Issues
5a] On cold start, does upper rad hose get hard before engine warms up? _______
5b] Any bubbles or oil film in coolant overflow tank? __no_____
5c] Any white slime on oil surfaces (dipstick, CDR, oil Fill cap)? ___no_______
5d] Excessive white smoke from exhaust on cold start? ___no______
5e] Excessive black smoke from exhaust under hard acceleration? _____some but not alot_____

6] Performance Issues
6a] Do you have gauges (boost, EGT) ? ____no_______
6b] Maximum boost under load? ____________
6c] Have you added a performance PCM (reflash) or Chip? ______no________
6d] Have you changed exhaust / downpipe / crossover? _____no___________
6e] Wastegate – mechanical or vacuum (OEM)? ________vacuum______

7] Temperature-related Issues:
7a] Single or dual thermostats? ______single______
7b] Have you replaced them lately? Manufacturer of replacements? _____no____
7c] Have you pulled and cleaned Radiator and coolers lately? ____no________
7d] Have you replaced the fan clutch? Manufacturer of replacement? ____no____
7e] (winter) Have you tested your antifreeze? Good to what temp? __________
7f] (winter) Are you using a winter grille cover? _____no______

 

[buddy]

So then the questions about the fuel you use, the current condition of the IP and the check for rotted fuel lines above the fuel tank are needed. You can try taking the fuel cap off to see if that helps, or drill a hole in it so it cannot make any vacuum in the tank which increases the chances for air coming into tiny holes.

Are these DTC codes since changing the IP? If so you got a bad IP or there is air in the fuel.

Edit: just saw your list....your glow time is way too long if it is a stock setup your Intake Air Temp (IAT) sensor and Coolant Temp Sensor (CTS) are messed up, reading much colder that actual. That still doesnt cause stalling.

If you have checked the grounds well, found two ground terminals on passenger head at the rear, with a total of three wire (one ring has two wires) then also check on the back of the engine closer to the fuel filter manager and the tranny dipstick mount. Other than that I would believe air is getting into the fuel, from pinholes in the lines or even a hairline crack in the fuel pickup inside the tank. Outside temps could be a factor for swelling pinhole leaks and what not.

Also, highly recommend not using solely Power Service, and dont use the anti-gel one unless its below freezing out. PS doesnt lubricate enough, better off using a quart of 2-stroke oil, or a couple quarts of Non-Detergent (ND) SAE30 oil. There are some good diesel additives for lubricity, but only a few specific ones, which is why those two common oils are easier to use.

 

[jrsavoie]

Also A new part doesn't mean a good part. Greg will vouch for that.

Do you have anybody near that has a 6.5 that you could switch PMD's with? It could also be the extension cable. Where did you get them and what did you get?

Did the truck run good with no dieing initialy after the new IP was installed? How about after the PMD?

Where are you located?

You could put a hose on the out port of the lift pump run some fuel and look for air bubbles.

 

[Acesneights1]

I would put clear tubing. between the fuel line and the inlet barb of the IP. Maybe 2 ft worth and see if there are any bubbles at all. That is easy to do. when it stalls does it start right back up or is it a bitch and you gotta hold your foot to the floor. Any smoke when it restarts ?

 

[JiFaire]

I'm wondering about Bk95's question; on the top of your IP is a filter harness... it has 4 wires, and just connects the IP harness to the IP.

You can unplug both ends of it and plug the harness directly into the IP, it should run just fine without it. Clear your codes, and see if they come back.

Also, as buddy says, dump a quart of non-detergent 30-wt motor oil into your next tank of diesel...

Also, those codes are common with failing PMDs in the 1994 system, especially with 5068 IPs. Don't ask me why they are more sensitive than the 5521s, I don't know, but they seem to be more finicky that way.. probably why GM obsoleted them.

So - free things to try: clear fuel line, look for bubbles. Remove OS filter harness. Quart of Oil to clear up the IP tolerances.

A little more difficult, check the PMD and the harness. Any little glitch in that system will cause you grief.

 

[buddy]

Thats a good question too, does the truck have a DS4-5068 IP or a 5067/5521 type DS4 IP.

Since it is a 94 3500 it could have come with the unique 5068. So unless you know what was on it and what was put on, you can check the PROM code inside the PCM to see what it should have, there is a 4 letter code starting with B on the removeable chip inside the PCM. A mismatch causes some stupid stuff to happen, but will run.

 

[TurboTahoe]

WOW I was not expecting so many replys thanks everyone

Dieselklad the PMD was new when relocated

bk95td all the fuses are good and I have checked the grounds (I think i got them all) going to check them again

buddy just the engine stops every thing else will stay on, if my memory serves me right the last time i checked the fuel pressure it was running about 7 psi looking for my guage to recheck it, strange how tools just disapear every time you need one

diesel slug yes the ground is still on the top of the IP

now today the air temp was below 80F and it ran like a champ with no shut downs at all

This does indeed sound electrical. In addition to repairing and replacing grounds (and adding new ones) I also recommend that you look at ALL the fuses in the fusebox, both under the hood and in the cab. I recommend you pull them, clean the legs (I used a dremel tool and a little wire brush), spray with Deoxit, spray the sockets as well, and replace them all. Mine were QUITE oxidized. You might also do this for other critical connections, such as the plugs for your ECU, etc. Remember, 90% of electrical failures are typically due to failed connectors.

Good luck!

-Rob

P.S. Welcome!

 

[Acesneights1]

You know re reading the OP Buddy has a valid point. I wonder if the shop put the wrong IP on it...Worth double checking for sure. You can read the numbers off it with a dentist mirror as well.