1994 6.5 Starts then Stalls

[Stevediesel]

HI everyone,

My 94 6.5 has been starting up, and then stalling a few seconds later. After 2-3 15 second cranks on the starter, it will fire up, then run rough for about 15- 20 seconds, before clearing out. It will run for hours with no problem, if I shut it off, it will start right up if it's hot. After sitting for 15-30 minutes, it's back to the same problem. I have Replaced the Pmd and moved it away from the manifold. I did replace the lift pump and fuel line a few years ago. I orignally had a stalling while driving problem, and moved the Pmd thus solving that issue. Recently it started the latest issue, so I just replaced the Pmd, it ran a lot smoother but still had the start/stall issue. Any input would be apreciated.

Thank you

[a5150nut]

Have you checked that you are getting fuel to the filter, then to the IP, and last to the injectors?

Is the Fuel shut off functioning properly?

[Stevediesel]

I just Changed the filter, and got a good stedy flow. I replaced The Shutoff solenoid about Two years ago, before I realized it was the PMD. It will run once it starts, after the initial stall. So I am guessing that the IP and injectors are getting fuel. The problem is random, but has been more frequent the last few weeks. I have been using the Stanadine perfomance formular additive, as recomended by a reputable diesel parts supply place in the Boston area.

[Stevediesel]

If one or more glow plugs are not working, could that contribute to my Start/Stall problem?

[a5150nut]

Have you cleaned and checked all your ground connections?

[16gaSxS]

If one or more glow plugs are not working, could that contribute to my Start/Stall problem?

Pull DTC codes. Codes & code pulling trick info in Members area, print out and check.

[DmaxMaverick]

If one or more glow plugs are not working, could that contribute to my Start/Stall problem?

The short answer is no. There are very few, extremely unique conditions that may cause this, but you'd have numerous other indicators.

Once the engine is running, glow plugs are not required to continue running. In conditions of very cold, or very low compression, they help to clear up the smoke and smooth out, but not having them won't cause a stall unless it's -40° or colder. Essentially, if the glow plug system is healthy enough to get it started, it's a non-issue after that.

[Stevediesel]

Pull DTC codes. Codes & code pulling trick info in Members area, print out and check.

I couldn't get into the members area, But I have an OBD1 scanner tool. I have tried to pull the code, but it just keeps flashing 12... Correct me if I'm wrong, but isn't 12 the No RPM code that should flash before, and after any codes are pulled? Thus meaning it's not throwng a code?

[Hooptybass]

Be careful unless you have a scanner that is MADE for diesel it prob wont work .

I have a real nice one from the cornwell guy and it says it will do diesel but it

wont . I was chasing phantom codes for weeks. Replacing this and that sensor

till got feed up and took it the my local diesel shop . And they told me unless it

made for the diesel or a tech 2 your outa luck


brian

[16gaSxS]

I couldn't get into the members area, But I have an OBD1 scanner tool. I have tried to pull the code, but it just keeps flashing 12... Correct me if I'm wrong, but isn't 12 the No RPM code that should flash before, and after any codes are pulled? Thus meaning it's not throwng a code?

As a paying member you should have access to the Member area.
Shoot More Power an e-mail and he can help you. There is a easy way to check with out a scanner for codes with the codes.

[Stevediesel]

As a paying member you should have access to the Member area.
Shoot More Power an e-mail and he can help you. There is a easy way to check with out a scanner for codes with the codes.

I actually could get into the Members area, but The part that has the code info, prompted me for a username, and password... I enter it then it said, either my info was wrong, or my browser wouldn't recognize something or another... I know about the paper clip trick, if that's what you mean.

[Stevediesel]

When it rains it pours... I was on a Job yesterday, for 7 Hrs. I went to start the truck at the end of the day, when it stalled, and would not start at all.. I ended up killing the battery. as I was waiting for a jump start,I figured I would crack the bleeder on the fuel filter, to see if it was getting fuel, when the plastic bleeder broke off. I ended up getting towed home, changed the filter, and got it going again. I came out this AM, started it right up, then it started leaking antifreeze, from the quick connector, on the top of the thermostat housing. I just fixed that, now it's back to the stalling issue

[Stevediesel]

Ok... So, I Started it up today and it did the same start/stall thing. So after I got it running, I opened up the T-Valve, and nothing happened... no fuel came out, no stall. So with the Engine idling, I unplugged the lift pump, and used a test light to check for current. When i got a good ground on the light, it lit up, but it was very faint.. Would this be an indication of a bad ops? or should I foucus on something else? My oil pressure gauge is reading about 60 psi. could the ops still give a gauge reading, but not enough current to run the lift pump?

[Stevediesel]

Ok... I opened the Tee valve, and blew into the hose a few times, and then felt air suddenly rush in. So I got the truck going again, and let it warm up. Then I opened the Tee valve, No fuel came out... after a few seconds it stalled. I went to Advance, and picked up an OPS. As I Was removing the old one, it just broke off right where the sensor goes into the fitting. I got the fitting out,with no problem, insalled the new OPS, and BINGO!!! she fired right up within 6 seconds!! Soooo... Let's hope that solved the problem! Time will tell. If not for this forum, I probably would have given up, and torched the Damn thing !!! Thanks a million to whoever started the Diesel Page!!!

[More Power]

Glad you got it going. Ordinarily, a bad OPS/Lift Pump won't cause a stalling problem. It's on the list of causes, because it can on occasion, but it's not near the top of the list of possibilities.

A lift pump not working usually causes a "missing" when the driver presses on the accelerator pedal, like when passing or on-ramp merging.

[Stevediesel]

Thanks Morepower... I never even thought about the OPS being the culprit. But after reading up on the operation of the lift pump, I figured I would focus on that for a while. I had stalling problems before, and it turned out to be the PMD. But this time was different, when the PMD was bad, it would only stall after the truck ran for a while. It would just shut off, as if somone reached over, and turned the key off. It would start right up and run fine for a while, then stall again. After a while it just stopped running all together. With the start, then stall, then hard starting, I thought it was someting else, but just bought a new PMD, only to have the same problem. I think, that maybe the LP was not priming the injector Pump, and it would just run untill the fuel filter ran dry of the leftover fuel from the last time it ran. So far, today it has fired up within about 6 seconds, and not stalled, four times... It seems to run better than it has in a long time. Hopefully, this problem is solved, once, and for all.

Thanks again !

[Deadeyedonk30.06]

I have a '94 K2500 as well that was doing the same, exact problem. Frustrated the heck out of me. I think it also ruined my starter because I had to crank and crank on it to get fuel back to the IP. I suspected the OPS but didn't want to sink any more of my hard earned cash into this truck and replace the OPS which "potentially" may have resolved the issue. I had already replaced and relocated the PMD, replaced the lift pump with the '93 version (somewhere on this site recommended this due to the higher output) but still had the stalling problem. I checked the voltage to the lift pump and it was floating between 9 and 12 vdc. So, very recently, I decided to throw caution to the wind and hardwire the lift pump to an open spade plug at the fuse panel under the dash. I found one of the spades that apply power when the key is in the "on" position as opposed to waiting for the OPS to get the pump pumping AFTER the motor is running (sorry, but what a crappy design GM). I understand the reason they did this (sort of), for safety. I wanted my LP to begin pumping when the key is on, to start the priming process (just like every other vehicle) while I wait for the glow plugs to get to temp. Again, somewhere on this site they recommended NOT directly wiring the LP because the pump would run and run and run... Whereas this may be true with wiring it to the Aux power somewhere, the spade plug ONLY provides power with the key in the "on" position (FYI! One downside is it also provides power with the key in the "backwards" position. Not good when you want to sit in your truck and listen to the radio while the kids are busy with their activities. But, I just insert the earbuds from my iPod and problem solved!). This allowed the lift pump to begin pressurizing the fuel system prior to starting and... VOILA!!, no more stalling! Problem solved! I'm exstatic, it hasn't stalled at all! Again, I want to stress that this method is not recommended by the "experts". But if, for some reason, I'm in an accident and am immobilized to the point of not being able to shut off the key to stop my LP from pumping, well, at that point, it will be the least of my worries. I'll be eagerly awaiting an ambulance! Until then, I'll take the chance to keep my truck from stalling.

[DmaxMaverick]

If a powered lift pump is required for a successful start (with an otherwise healthy fuel supply system), then your IP is failing mechanically. A new pump is in your near future.

[Stevediesel]

Well... almost a month later, and she's running great ! Next mission, Glow plugs... Stay tuned .