Shuts off while driving - Stalling

[Eddys]

1994 Blazer Silverado with 6.5TD. It happened a few times the truck will just shut off while driving. It will start right back up again and will not trip the service engine soon light. The truck runs fine besides that. The problem is intermittent. Has anybody seen this or experienced this problem?

[ 12-17-2004, 05:37 AM: Message edited by: JohnC ]

[More Power]

This is a somewhat common problem that has been discussed many times here in this 6.5L Turbo forum. A search for the word "stalling" in this forum will yield lots of reading on this subject.

Jim

[RANCHMAN]

THAT STALLING PROBLEM IS ONE OF THE THINGS THAT HAPPENS WHEN THE DS4 SOLENOID DRIVER STARTS TO FAIL. THAT'S WHAT MY TRUCK WAS DOING AND REPLACING THE DRIVER FIXED THE PROBLEM. CHECK AND SEE IF YOU ARE GETTING A CODE 35. THIS PROBLEM HAS BEEN DISCUSSED QUITE A BIT ON THIS FORUM. CHECK THEM OUT

[ucdavis]

Given the age/mileage of the rig, could also be the ingition "switch" which is not the key switch, but a device in the steering column below the key switch. It gets worn, & breaks contact of the 12V ingition circuit. If you can wiggle the steering column & fix the problem, it is the switch. It gets worse over time, due to continued wear.

[Barry Nave]

The new,# 2 SOL-D has been working great.

[DeezlStinson]

Howdy all,

Yeah....Mine has been doing this for last couple of weeks. Today it finally would not start at all. (after I get it towed home) I'm going to do a little electrical trouble shooting. I have a PMD to install but I want to be sure that's what the problem is. I got DTC-13 and DTC-36 (1994 model)

I still think it's a 12v supply problem...possibly the ignition switch or associated wiring. If not I'll replace the PMD. I'll also probably have a look at the transistors in the PMD..I have a hard time believing that 2 PNP/NPN switching transistors and a few associated parts should cost upwards of $300 or more. We are really getting ripped off on thse things.(especially since they are so poorly designed!)


More to come!

Cheers (?)

Rick

[ 12-27-2004, 09:00 PM: Message edited by: DeezlStinson ]

[Chad Mac]

I feel like a professional on this subject because I have fixed stalling problems on my truck on 4 seperate occasions.

The first time was the ignition harness that was mentioned earlier. When mine went out it would stall while driving and no dash lights would come on. I could work the key switch back and forth til the dash lights came on and it would start right up. New ignition harness and problem solved.

The second time was the infamous PMD/FSD. When mine went out it would stall while driving and sometimes start right back up, sometimes I would have to crank on it for a while. New PMD/FSD and problem solved.

The third time was the also infamous OPS. It would only stall shortly after restart when the truck had been driven and shut down for a short time period and would require some cranking to get it going again. New OPS and problem solved.

The fourth time was the in-line fuel lift pump that assists the injection pump. Symptoms were serious hiccups under acceleration and stalling after startup with lots of cranking to get it going again. My lift pump sounded like it was working fine (humming when the key was turned forward and when the truck was running) but all it was doing was making noise and not pumping any fuel. New fuel lift pump and problem solved.

I don't know how to explain it but I love the truck. My next truck will be a 6.5 also. I guess because I know the engine so well that I feel like I can diagnose and fix almost anything on it now. Good luck with your problem!

[DeezlStinson]

I have had wiring problems, lift pump and PMD so far. I've never had the OPS fail (Optical sensor?) Nor have I had a problem with the ignition switch. Those are probably next huh?

This time it was the PMD. I think this is going to be it for me. I'll either go to a mechanical injection pump or I'll get rid of this thing and get a New pickup!

Nearly 11 years and 138000 miles is long enough to keep any vehicle!


Of course this is the place where people cry about their problems a lot!

I wonder how many 94-99 GM diesels had NO problems by comparison? The people with no problems just drove them until they got tired and got something else.

Cheers everybody!

Rick

Originally posted by Chad Mac:
I feel like a professional on this subject because I have fixed stalling problems on my truck on 4 seperate occasions.

The first time was the ignition harness that was mentioned earlier. When mine went out it would stall while driving and no dash lights would come on. I could work the key switch back and forth til the dash lights came on and it would start right up. New ignition harness and problem solved.

The second time was the infamous PMD/FSD. When mine went out it would stall while driving and sometimes start right back up, sometimes I would have to crank on it for a while. New PMD/FSD and problem solved.

The third time was the also infamous OPS. It would only stall shortly after restart when the truck had been driven and shut down for a short time period and would require some cranking to get it going again. New OPS and problem solved.

The fourth time was the in-line fuel lift pump that assists the injection pump. Symptoms were serious hiccups under acceleration and stalling after startup with lots of cranking to get it going again. My lift pump sounded like it was working fine (humming when the key was turned forward and when the truck was running) but all it was doing was making noise and not pumping any fuel. New fuel lift pump and problem solved.

I don't know how to explain it but I love the truck. My next truck will be a 6.5 also. I guess because I know the engine so well that I feel like I can diagnose and fix almost anything on it now. Good luck with your problem!

[rjschoolcraft]

My uncle has a 96 with 5-speed that has not given the first problem. It has somewhere near 70,000 miles and is completely bone stock. He has towed a travel trailer with it to NASCAR races and uses it around the farm. He's the reason I bought a 6.5 in the first place.

[DeezlStinson]

Hi Ron,

We have to remember that this is the place where mostly people with problems came for help. There are probably thousands of people who had no problems at all. The average person keeps a vehicle 3-4 years, 60,000-80,000 miles and either trades it in and/or sells it and gets another one.

It's "us people" who choose to keep them to well over 100000 miles (11yrs in my case) to squeeze every last penny out of them (because it cost much to begin with!)


We are lucky to have a dedicated group of people like Jim, Lee and others who pulled us all together so we wouldn't be completely dependant on the dealers.


Happy New Year to you all!


Regards,

Rick

Originally posted by ronniejoe:
My uncle has a 96 with 5-speed that has not given the first problem. It has somewhere near 70,000 miles and is completely bone stock. He has towed a travel trailer with it to NASCAR races and uses it around the farm. He's the reason I bought a 6.5 in the first place.

[Eddys]

I will be bringing it in this week to the dealer. I'm pretty sure it's the same thing as last time THE PMD/FSD it should still be covered under the extended warranty. This morning it did it again just shut itself off on the highway on way to work I restarted it on the fly and kept on driving. I'll keep you guys posted on the turnout from the dealer.

[panchosteam]

Hi guys,about this PMD problems,how about making some kind of air entrance from the front of the truck, and maybe with some kind of pipe or something create the entrance for the air and direct it right on the PMD,or maybe even make a litle breather from top of the hood, so cooling air can help on this heating problem. May be it will help who knows it is only an idea, i don't have one of this PMD'S on mine, went mechanical
hope this helps.

1984 GMC 3/4 TON PICK UP NOW WITH 6.5 TD AND HEATH'S TURBO MASTER


9

[BUZZ]

Rick,
The DTC 13 is related to fuel shut down solenoid.
The deep well socket looking thing on top of IP, in case you did not know.
I am having shut down issues and today no start, first crank of the day. I plugged up a spare, used PMD and still no start. Well this is new. Also noticed a click click click when cranking but no run. This sounded lots like a loose spark plug wire on a gasser, you know, spark sound. Well I played around with wire and plugs still nothing. It finally started to run and shut back down. I then unplugged the fuel shut down sol., ran a straight 12 v to the shut down sol. and started right up. I then checked for 12 v at the now disconnected plug, and I read 12v. So I am now thinking not PMD but the 12 v feed going to this solenoid. Possible 12v but low current from ignition switch or bad grounds. OR maybe sol had trash or stuck and straight 12 v loosened things up a bit. Any way I plugged everything back up factory style and has run with out hitch today. Wonder if the click sound I heard was the fuel shut down sol opening and closing while cranking.
I have cold start issues and will run a straight 12v to the sol tomorrow and see if cold starts are changed.
I get paid by the word.
Thanks
Buzz

[DeezlStinson]

Hi Buzz,

Yes ...for a 94/95, DTC 13 is the shutdown solenoid. I thought it strange that I would get 36 and 13 but I don't know when they set since it always re-started each time.

By by the way DTC 35/36 are directly related to the PMD and the main fuel solenoid (like you said the shut down solenoid is different)

The shut down solenoid gets power from the ignition switch and the ground connection for it comes directly from the computer. There's a few plugs between so any loose/poor connection in either the ground or power (in those plugs) will cause a DTC13 when the key is on. (it sounds like your problem might be an ignition switch)

I had this problem with the 15 pin plug that caused this too several years ago.

I did replace my PMD last week and the thing starts and runs fine now.

I still have a problem with the PMD failures. I still think it's a mechanical failure possibly internal in the PMD. Those Motorola transistors just don't seem to get hot enough to fail due to heat. Even though they must be derated about 1.5 watts per degree above 25C They're still rated at 250w and 200 degrees C... I haven't measured the output current to the fuel solenoid but I don't think it draws much more than about 10A or so and that's pulse width modulated meaning that the duty cycle is not continuous. Has anyone actually measured the voltage/current output of the FSD?(You'd need a scope and a little test circuit to do it of course!)

I suppose there's other electronic devices in the PMD but I think it's simply a couple of switching transistors and a few other passive parts. Solenoid driver circuits are actually very simple.... Makes it about $30 in parts! MAN are we getting ripped off!.... Never mind that the PMD is possibly incorrectly/poorly designed too!

Anyway so far mine is running as good as ever so I either fixed it by cleaning up the plugs, replacing the PMD or reconnecting the system ground. (I also did a complete battery connection cleanup)

Hope yours goes as well!

regards,

Rick

Originally posted by BUZZ:
Rick,
The DTC 13 is related to fuel shut down solenoid.
The deep well socket looking thing on top of IP, in case you did not know.
I am having shut down issues and today no start, first crank of the day. I plugged up a spare, used PMD and still no start. Well this is new. Also noticed a click click click when cranking but no run. This sounded lots like a loose spark plug wire on a gasser, you know, spark sound. Well I played around with wire and plugs still nothing. It finally started to run and shut back down. I then unplugged the fuel shut down sol., ran a straight 12 v to the shut down sol. and started right up. I then checked for 12 v at the now disconnected plug, and I read 12v. So I am now thinking not PMD but the 12 v feed going to this solenoid. Possible 12v but low current from ignition switch or bad grounds. OR maybe sol had trash or stuck and straight 12 v loosened things up a bit. Any way I plugged everything back up factory style and has run with out hitch today. Wonder if the click sound I heard was the fuel shut down sol opening and closing while cranking.
I have cold start issues and will run a straight 12v to the sol tomorrow and see if cold starts are changed.
I get paid by the word.
Thanks
Buzz

[Yangtze]

I've recently puchased a (Canadian) 97 1/2T Silverado 6.5L at an auction. 121000 mi. Now you understand why it was at the auction. I didn't - I'm a diesel newbie - ignorant of 120000 mi warranties. I've also never done a forum before, nonetheless - I'll proceed. When driving the vehicle home from the auction I noted the RPMs seemed excessive - 2200 for 60 MPH. The error codes were 118, 223, 236,380, & 405. Took it into the dealership - reported 12 severed (Cleanly) wires going into the PCM behind the glove box and spliced all - engine ran intermittantly and spat out codes 223, 251, 370, 380, & 405. They finally cleared those, got it to run - markedly improved performance and stated they believed the EGR passages should be cleaned and the fuel filter should be replaced as the lift pump pressure 'appeared low'. Picked it up from the dealership and it stalled driving off the lot....... and numerous times since - both under load and going uphill. I've changed the filter and checked the lift pump pressure - 4.5 psi. Since becoming a member yesterday I've read with rapt interest the voluminous message traffic irt this subject - stalling. I took the vehicle back to the dealer and asked them to investigate the stalling and steered them towards the FSD. They insist on revisting the PCM harness and may perhaps work there way over to the FSD. Seems a plausible approach given someone had destroyed the harness and it IS possible a connector or conductor is degraded .....but all your postings about the FSD are very compelling - will update when known.

IRT the SOL-D product - as a supervisory electrical design engineer for the US Navy I can't over-emphasize the importance in 1st article testing of components that are to be placed in service in mission critical systems - whether it's the propulsion system on a nuclear aircraft carrier or your vehcile carrying your wife and children through a blizzard or across the desert - it had better be 'proven'. One observation from the SOL-D feedback comments is that the suspect diode was rated for 150 C - is that rise above ambient - or - absolute ? If ambient - what does your specification state as ambient ? Doesn't encapsulating the diode degrade it's thermal properties by trapping the dissipated heat ? I applaud this type of after market platform (SOL-D) and it's premise of attempting to improve/replace an OEM product - and I may ultimately install one as my confidence level in my dealership is waning - but I don't desire to be a participant (at my expense) in the test phase twice (dealership and SOL-D).
Having said all this - anyone ever encounter similar issues - ie cut harnesses ? My bet is the previous owner astutely determined how to bypass the PCM and keep it running (degraded performance) and once > 120000 - took it to the auction.
thanks

[Heilander]

Yantze, you mentioned that this was a Canadian truck, which means that the odometer would display in kilometes - does it show 121,000km or did you do the conversion from 197,000km to miles?
- Just curious.

[Eddys]

Got the Blazer back from the dealer on Friday. Result like I suspected from the begining the PMD! I'm thinking of purchasing the remote PMD package from A1 customs. Has anyone bought anything from them?


later

[rjschoolcraft]

I would not recommend that guy. Lot's of negative feedback. Kennedy Diesel or Heath Diesel would be better choices, with my preference being Kennedy.

[JohnC]

Originally posted by Eddys:
I'm thinking of purchasing the remote PMD package from A1 customs. Has anyone bought anything from them?

All I will say is that he is banned from this and at least one other site.

[DILLIGAFRI]

Went thru the stalling prob with my 98 Cured the prob with Bill Heath's unit. No problems and a clean install. High reguards for his product
Dave