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Running issues

S

srhoo

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1994 chevy 6.5 turbo diesel 3500
glow plug light doesn't stay on wont start , even when warm when they do it starts.
when running will die at will, then may start or not, may run an hour or 2 then die like you turned off ignition or run 5 mins an die.
unit has 140K on it never had any issues had previous moved the fuel pump module to fender, new fuel pump few years ago. disconnected optical sensor no difference. had in shop they couldn't fix but not sure how good they were.
Where to start.

Thanks
 
Cut and paste the questions from this post.
Make sure you DO THE TEST on a few steps that needs testing.
Post it back with your results of the test or information.

6.5 Engine Diagnostic Troubleshooting Checklist

6.5 Engine Diagnostic Troubleshooting Checklist Copy and paste this checklist into a new post, then answer all the questions by typing in your data into the (red) blanks as indicated - click in the middle of the blank, start typing. Problem: Explain your problem in concise...
www.thetruckstop.us
 
Welcome to the forum @srhoo there are lots of great knowlagable folks here to learn from. were all here to help each other out :)

Follow those steps JMJNet linked. it will get you in the best direction. from your description it could be a bad connection on the PMD or a failing PMD. what all did that shop you take it to do or what have you done up to this point when this issue arose?
 
Sounds like a classic PMD or extension harness issue. Wiggle the connection and see if it drops out. Do you have a spare PMD to try?

Also PMD failure can be caused by a bad injection pump fuel solenoid. So if it turns out to be a bad PMD it may also need an injection pump.
 
Rockabillyrat said:
Sounds like a classic PMD or extension harness issue. Wiggle the connection and see if it drops out. Do you have a spare PMD to try?

Also PMD failure can be caused by a bad injection pump fuel solenoid. So if it turns out to be a bad PMD it may also need an injection pump.
Click to expand...

We had in shop for over a month, they replaced the PMD (twice) with no help. finally towed home. We've tried disconnecting the Optic fuel sensor no help, wiggled wires while running no change. Bought a cheep OBD 1 scan tool checked codes came up with 18 then 17. tried wiggling the crank sensor connection and wires no change. I've felt the fuel pump solenoid click when started. when it dies its just like turning off key, it doesn't run bad when running no black smoke but down on power. when turning on key the glow plug light goes off immediately and its hard to start, Some times the glow plug stays on normally and it starts right up.
We've ordered a new crank sensor will be here in a couple days. at this point we're throwing parts at it, no shops in town want to work on it "to old" and its a car hauler (long)
 
Year: _1994_____
- Truck model and class (ie: c2500) __C3500_______
- Automatic or Standard __auto________
- Mileage: (indicate miles or km) __140k miles_______
- Replaced parts and mods (IP, PMD, chip/PCM, TM, injectors etc) _PMC__________
- Model: ‘S’ or ‘F’ engine, NA or Turbo, EGR? ___TURBO___________
- Ambient outside temp: (indicate *C or *F) __80F________
- What fuel are you using? (#1 Diesel, #2 Diesel, Bio, VO, WVO, etc) ___PUMP______
- What fuel additives are you using? _NONE__________
- Where are you located? _YUMA AZ____________

General maintenance: inspect and evaluate the condition of each. When were they last changed?
- Air filter _1000MILES________
- Fuel filter 1000 MILES_________
- CDR Valve? _________
- Coolant – last flushed/replaced at _____________
- Oil – synthetic/regular, changed at __DELO 1000MILES_________
- Batteries – state of charge, (matched set) replaced at ____GOOD_________
- Battery cables and grounds (removed, cleaned and tightened): __2 YEARS ____________
- Glow Plugs - how many miles on them? _140K________ What type? _____________
- Injectors - last changed at ___OEM 140K MILES____________


History: (Describe how the problem first appeared.)
- What were you doing when it happened? __DRIVING DOWN HWY 40 MILES AFTER FILL UP ____________
- How was the truck running fine before this problem appeared? __YES___________
- 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 AND 18______

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

1] Starting:
1a] Does the engine start? _Y________
1b] Does the engine crank over? Y________
1c] Are your batteries fully charged? ___Y______
1d] Have you removed, cleaned, and tightened all battery connections? __N______
1e] Does your Wait to Start light come on for a time? How long? _________
1f] Does your glow plug light come on? __Y_______ For how long? 1 Second some times other times 10 seconds_________
1g] Do you see smoke from the exhaust while cranking? What color? __N______
1h] Does the Service Engine Light Glow during Start/bulb check? __Y______

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? ___N________

3] PMD / IP Issues
3a] Location of PMD (on pump, on intake, remote mounted) __RM_________
3b] Condition of Extension harness (if used) Vendor or Homemade? ___VENDOR______
3c] Condition of grounds / ground wires to IP / PMD. Check Harness. ___GOOD______
3d] PMD Make: __NOT SURE SHOP PUT ON_________
3e] PMD Age: __30 DAYS___________

4] Stalling Issues
4a] Do you experience stalling only when hot? ____N________
4b] Does it stall under particular circumstances? (ie hit bump, or on accel) _N_____
4c] Does pouring cool water over the IP seem to help with restarting? _________
4d] Is stalling momentary (engine recovers)? ___N______
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? __N_______
4h] Changes to dash lights or instruments during stalling events? ___N________

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? __N_____
5c] Any white slime on oil surfaces (dipstick, CDR, oil Fill cap)? ___N_______
5d] Excessive white smoke from exhaust on cold start? _N________
5e] Excessive black smoke from exhaust under hard acceleration? __N________

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? ___N___________
6d] Have you changed exhaust / downpipe / crossover? ___N_____________
6e] Wastegate – mechanical or vacuum (OEM)? _____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.

___
 
dbrannon79 said:
Welcome to the forum @srhoo there are lots of great knowlagable folks here to learn from. were all here to help each other out :)

Follow those steps JMJNet linked. it will get you in the best direction. from your description it could be a bad connection on the PMD or a failing PMD. what all did that shop you take it to do or what have you done up to this point when this issue arose?
Click to expand...

Helping a friend with his 1994 c3500, I have some automotive background but not with diesels. I have better computer skills than he does so I'm doing the research.

He has owned this truck since 1996 140k miles. Was traveling to Yuma AZ from Washington after fueling in Calif near Bakersfield truck ran good for 40 miles then died did restart but would shut off at will, got towed to a garage. Shop replaced the PCM twice, not sure what else they did had it over a month gave up on it. He picked it up with a goose neck trailer and brought to Yuma the pump was replaced 20 years ago with a Bosh the PMC was moved to the fender well been running good ever since no issues until now.

What I have done since getting involved, bought cheap OBD 1 code reader came up with code 18, disconnected optic sensor mad no difference in running or dying. but now get a code 17. checked the fuel solenoid felt it click when starting wiggled the wiring associated with the PMC and remote placement no change, did locate the crank sensor wiggled wiring and connector. scratched head kicked tire made no difference except made me feel better but now have sore foot. out of desperation ordered a crank sensor will be here in a few days.[/QUOTE]
 
Last edited by a moderator:
looking at code 17 and 18, that is showing the optic sensor position is out of spec or could be just set due to unplugging the sensor. try these steps.

first with the key on use a test light and check all fuses in both the in-dash box and the under hood box. verify all are good and well seated in the sockets.

then next step disconnect both batteries to clear the codes. while disconnected. look up by the tranny dipstick tube, there will be three ring terminals crimped to wires and bolted to that are of the intake. remove them and clean them well, check the crimp connections. reinstall. these are the computer grounds. also on the top side of the injection pump there is a single ground lead on one of the torx bolt near the optic sensor. verify it is also good.

third step. disconnect the PMD (pump mounted driver) extension harness at both ends, up by the injection pump and at the PMD. verify there is no corrosion or moisture inside the connectors. look in the plugs and verify there is a resistor installed. there should be what looks like a tiny circuit board pushed deep inside the connector of the PMD, you might need to unbolt the PMD with the heatsink to see in there. reinstall and verify the PMD heatsink is mounted in such a way that it's grounded to the truck frame.

last step, clean the battery cables and connections, make sure there is no corrosion or swelling with in the cables at the crimps on the battery lugs. reconnect both batteries and give it a whirl. take note if the glow plugs cycle for their proper time before cranking and is not consistent each time the key is turned on after a 30 second waiting period.

report back on your findings.
 
one more item to look for.... on the optic sensor connector of the harness. if you see what looks like an extension measuring about 6 inches long with a black square box inline on the extension, remove it from the harness and reconnect the optic sensor to the main harness. that black box extension is a noise filter and is known for giving issues. it's not needed and can be tossed.
 
also I forgot to mention on the fuses, make sure none are missing! when I first got my truck, my glow plugs weren't working and discovered a fuse in the under hood box labeled ECM-B was missing from the socket. after installing one, they worked!
 
You need and injection pump

GM TSB #67-63-04: HARD START, NO START, START STALL, ROUGH IDLE

CONDITION:
SOME OWNERS MAY COMMENT ON THE FOLLOWING CONCERNS: HARD/NO START, START STALL, ROUGH IDLE, AND ENGINE STUMBLE WHEN OPERATING UNDER HIGH TEMPERATURES AND LOAD CONDITIONS. RELATED DTCS: (1996: P0251, P0370, P1216, P1217), (1994-95: CODES 17, 18, 35, 36).

CAUSE:
A DISTRESSED OPTICAL SENSOR CIRCUIT BOARD MAY CAUSE NO OR IMPROPER CAM SIGNALS WHICH AFFECTS PUMP TIMING. ALSO, LOW LUBRICITY FUEL MAY RESULT IN WORN INJECTION PUMP CAM ROLLERS CAUSING LOW FUEL OUTPUT.

CORRECTION: AN ENHANCED FUEL INJECTION PUMP WAS RELEASED BEGINNING WITH THE 1997 MODEL YEAR THAT CONTAINS AN IMPROVED OPTICAL SENSOR. IN ADDITION, NEW CERAMIC ROLLERS ARE ALSO RELEASED WHICH WILL HELP PREVENT ROLLER WEAR DUE TO LOW
 
There are a set of question on Lift Pump that you have not answered.
You need to somehow energize the LP and see if it is pumping fuel.
Also, due to water in fuel possibility, I suggest while the LP is pumping fuel (assuming it works), you need to open the drain valve and drain the fuel.
Then, change the fuel filter and also clean the fuel filter canister (may have to take it off).
Reinstall it and turn the LP on again to bleed using the bleeder valve.

I agree with above, check all the fuses.
 
JMJNet said:
There are a set of question on Lift Pump that you have not answered.
You need to somehow energize the LP and see if it is pumping fuel.
Also, due to water in fuel possibility, I suggest while the LP is pumping fuel (assuming it works), you need to open the drain valve and drain the fuel.
Then, change the fuel filter and also clean the fuel filter canister (may have to take it off).
Reinstall it and turn the LP on again to bleed using the bleeder valve.

I agree with above, check all the fuses.
Click to expand...
I use a 12 volt fuel pump to clean the filter bowl - sometimes an old lift pump that may not be good enough to run, but still moves fuel. I dump some Sea Foam in the Bowl, do some cleaning and suck it out.

A 95 and older needs the lift pump relay upgrade with prime feature.

I usually jumper the lift pump & run about 1/2 gallon of fuel out the T drain into a gallon pickle jar. Leave it sit and look for water bubbles on the bottom. Sometimes you can see crud right away.
 
A repair book/manual for one of these is mighty handy.
A person should have the book for every piece of equipment that they own.
I used to have a Haines manual for my older gas truck, 1993, abd I kept that book when I got this 2000 K3500. I found that the Haines book did not have near the information for the 6.5 diesel as was needed for even daily maintenance and simple repairs. The Chiltons book is much better and goes into some great detail about repairs, and, wiring diagrams.
A good wiring diagram will show You which is the hot wire connection in the plug for the lift pump relay. You can remove the relay and cross that hot wire to the LP wire and have the LP run without the engine running. That wire to the LP can be crossed to a battery + terminal and then the key does not have to be on to run the LP.
That is great for diagnosis and also for purging air from the fuel filtars.
After You get the running issues sorted out, look into leroydiesel.com and get his improved LP relay wire harness with the push to prime switch. He has a lot of other nice items for the 6.5 platform too.
 
MrMarty51 said:
A repair book/manual for one of these is mighty handy.
A person should have the book for every piece of equipment that they own.
I used to have a Haines manual for my older gas truck, 1993, abd I kept that book when I got this 2000 K3500. I found that the Haines book did not have near the information for the 6.5 diesel as was needed for even daily maintenance and simple repairs. The Chiltons book is much better and goes into some great detail about repairs, and, wiring diagrams.
A good wiring diagram will show You which is the hot wire connection in the plug for the lift pump relay. You can remove the relay and cross that hot wire to the LP wire and have the LP run without the engine running. That wire to the LP can be crossed to a battery + terminal and then the key does not have to be on to run the LP.
That is great for diagnosis and also for purging air from the fuel filtars.
After You get the running issues sorted out, look into leroydiesel.com and get his improved LP relay wire harness with the push to prime switch. He has a lot of other nice items for the 6.5 platform too.
Click to expand...
On the 94, I think I just pulled the fuse on the passrnger side and stuck a spade connector in it. I made up a short fused alligator wire with a safety toggle switch. I'd flip it on and off as desired.

That was before I installed a permanent toggle switch to run the lift pump for diagnosis and priming.. I never liked Leroy's momentary switch. I prefer an on/off. . I think he may have offered that later.

I also prefer a mountable relay socket as opposed to mountable relay with seperate wires running to it.

Much easier to mess with, if the need ever arises.
 
MrMarty51 said:
Yeah, the switch on the harness I got for My 2000, it is a press to turn on, it stays on until it is pressed again to turn it off.
The harness all the way back to the LP is of the highest quality.
Click to expand...
Absolutely. Even though I would do a much better job now, I would not make my own harness again. Too easy and too fast to just by Leroy's plug and play.
 
srhoo said:
"to old" and its a car hauler (long)
Click to expand...
srhoo said:
after fueling in Calif near Bakersfield
Click to expand...

I hope this is personal use and "Not For Hire". If this is hauling cars commercially in California the owner and driver had better be aware of the Retro-Laws there banning old Diesels for commercial use that do not have a DPF filter, emissions equipment. In other words this old Diesel doesn't belong in CA commercially with few exceptions that may have expired by now.

#1 thing to check on these engines is "Air In Fuel."
Clear return line off IP. Look for bubbles.
What's the fuel pressure at the water drain? Lift pump on via a wire jumper etc.

Lift pump making noise means NOTHING!

The engine WILL NOT RUN on fuel full of air from a kinked hose, clogged tank sock, or intermittent lift pump (bad itself or from a bad Oil Pressure Switch feeding it low voltage/current.) Gasoline Smell or water/bugs are also a problem a clear jar of fuel from the water drain can show you.

Fuel filter is how old? Of course you don't assume anyone knows where or what it is... You are "Starting Over" your troubleshooting.

Is the PMD on it now NEW or did they put the old back on as it didn't fix it?

The ONLY TWO PARTS you EVER throw at these are a PMD and the extension cable. They are so unreliable and flaky backed by Primitive Artificial Stupidity for a Computer/PCM/ECM that has no way to know it failed. Esp with the 'delay warranty claim' timers that don't expire to set a code before the engine is "not running" and the software mode switches to Not Running. The timers allow a flaky connection bothered by a pothole to not cause you trouble as well.

Replace the PMD extension harness with a Made IN USA from LeroyDiesel


srhoo said:
glow plug light doesn't stay on wont start , even when warm when they do it starts.
Click to expand...

Glow Plug Light.

You are new to Diesels. Cheap parts engine to start learning on. However you need an understanding of WTF Glow Plugs are and how they work, NOW. Bluntly the light IS supposed to go out. You turn the key to RUN without starting the engine. Wait for the Glow Plug Light to go out. The Glow plugs are now hot and will help light the Diesel fuel from HEAT in the pre-combustion chamber. Put Key to start and engine should start immediately. The Glow Plug Light may cycle after the engine is running. If the engine is hot enough there is NO need for Glow Plugs and they WILL NOT TURN ON.

Do not bother cranking over 20-30 seconds. Seriously: the 10HP starter is overheating to ruin and the Glow Plugs have cooled off to USELESS. (Batteries also now HATE you after 30 seconds and are unwilling to give it a full push the next time.) Wait at least 2 min before trying again. A big Battery Booster charger can ruin Glow Plugs. Remove Charger before starting attempts.

There is sometimes a starting procedure of the back of the driver sun visor. RTFM (Owners Manual) also helps here.

DO NOT USE STARTING AIDS. The sticker is a fair warning you can instantly ruin the glow plugs and engine. (Look up Diesel Engine Runaway as one of several ways to kill it. Slowly is bent rods.) IF The fireball coming back out of the intake from working glow plugs doesn't send you to the burn ward.


Video of it's start sequence via YouTube linked here can help.
 
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