• Welcome to The Truck Stop! We see you haven't REGISTERED yet.

    Your truck knowledge is missing!
    • Registration is FREE , all we need is your birthday and email. (We don't share ANY data with ANYONE)
    • We have tons of knowledge here for your diesel truck!
    • Post your own topics and reply to existing threads to help others out!
    • NO ADS! The site is fully functional and ad free!
    CLICK HERE TO REGISTER!

    Problems registering? Click here to contact us!

    Already registered, but need a PASSWORD RESET? CLICK HERE TO RESET YOUR PASSWORD!

scary problem. I need the big brians to wiegh in on this

devildogadam

devildogadam

Active Member
Messages
278
Reaction score
83
Location
Yakima WA
So I was sitting at a light on my way home enjoying the wonderful 29palms heat when all of the sudden my truck went wide open throttle Balls to the walls. I was lucky to have my foot already on the brake, I stomped on the brake pedal and she poored black smoke and started to spin the tires. Cars all around where terrified. I kept my foot on the brake and pumped the fuel pedal a few times then after a bit it quit. But then I had no throttle response. Shut it off and restarted it would rev up and run away. Then after a few more restarts it would idle fine but no real throttle response would only do about 10mph and misfire and rev and stall. Pulled over and let it sit for about 15 minutes then it ran fine on the way home. This is the first time it has done it in drive but lately when idling it would randomly rev to red line then back like someone was snapping the throttle. The only code it threw was a code 35. So I am at a bit of a loose
 
You most likely need a new PMD. Your accelerator pedal could be a problem, as could the optic bump - who did that, by the way? It is usually used to compensate for a stretched timing chain, and is a controversial modification.

Anyway. Runaways caused by PMD failure are fairly common.
 
Adam,
AKdieseldriver and I experienced a similar situation while hot footing my truck around in Vegas. It had done it a while before here at home months earlier. First instance I had issues with fuel supply system. Second time I exchanged PMDs under warranty. No more issues. Old unit was a D-Tech mounted on the skid plate. New on is Stanadyne Grey.

Also, check the PMD Harness for chaffing etc.

APP has three check circuits and a failure in any of them will code.

On edit, check your phone messages....:hello:

.
 
NO SCANNER... i love buying tools but that one is still just a bit pricey for me.

and Paul, thank you so much for all the help, i cant say that enough. And yes, i will move that heat sink to the bumper and stop being stubborn
 
devildogadam said:
NO SCANNER... i love buying tools but that one is still just a bit pricey for me.

and Paul, thank you so much for all the help, i cant say that enough. And yes, i will move that heat sink to the bumper and stop being stubborn
Click to expand...

Happy to help. D-Tech spare on the way and should be there Thursday. Since my warrantied kit came with a Grey unit and the new IP from the build had one as well, I couldn't use it anyway.
Use the savings and call a site vendor and get an extension harness shipped out yesterday! Forgot you had that thing in the engine bay....no wonder.

NVW said:
The last item on this page is the best scan tool for 94-95 6.5's http://www.leroydiesel.com/Page_2.html
Click to expand...

This and the harness will run you a lot less than a new PMD....HINT!:thumbsup:
 
I already have a extension harness. Been sitting in my tool box for a while, I was just being lazy and now I am paying for (paying a lot less thanks too you Paul) in reliability and embarrassment.
 
I was just looking at the thread title, and wondering...

Who the hell are the Big Brians?

FF_020207_bigBrian_t600.jpg brian-wilson-big-lebowski-shirt.jpg
 
Ok gents, I change my fuel filter and added some fuel lubricant, but that didn't help. Thanks to the generosity a member here I got a new pmd,
I put it on an extension harness I had been holding on to. Wouldnt start, found a broken wire on the harness so for now it it back on my fsd heatsink and it works great. Pmd solved all the problems. So i ordered a new harness from leroy diesel and will move it once it comes in.
 
Glad to see your back running again, at idle when you want it to be end the scary problem. Unfortunately with a ds4, a spare good pmd is just a necessity like a spare tire. Just be quick to reach for the key to kill it when in doubt.

This has me to thinking again about the Toyotas and the accidents and law suits, vs this issue.
By the time I saw the thread it was already responded to about the pmd and I think "pmd x 4" was kinda pointless for me to add in. Any run away starts with blaming the pmd, and once in a blue moon is something different. But How many people out there don't know about the problem. I really cant believe there has not been an accident or two due to the bad pmd issue.

"No really dad, it just went full throttle by itself- I wasn't trying to show off to Tommy." What about explaining that to a cop or judge.

I am looking for a truck for my currently 14 year old son, but will not consider the 6.5 w/ ds4 for him because of it. My last p/u with a 6.5 & ds4 had me almost rear ending a frikkin Ferrari in a drive through- last ds4 for me. Where I live, you cannot retro fit a vehicle with equipment older than the year of the vehicle. A 1990 truck can get a 1996 engine, but a 1996 can not get a 1990. All in the name of smog pollution. Anything I would get him would have to come stock with a db2. I know how to convert a ds4 to a db2, but can't get it registered here because the fuel system is part of emissions system.

Sorry for the psycho left turn on your thread, it just kills me to see this issue not being resolved by GM. bad window regulators, or interior door handles-ok, but GM should not be allowed to not fix something that is plain dangerous out there when it is clearly a case of not spending the $ to make a better part.
 
In your long term plan, rather than just a spare PMD, though cheaper, I would purchase a complete kit from either Leroy or Heath and install that. Use the SSD and current PMD as the spare. That way you aren't in the desert trying to swap a PMD onto a heat sink using a flash light, hoping to have the right sized Allen wrench in your glove box and a spare tube of Arctic Silver laying around too. Just plug and play if and when needed.
 
Yes the fact that gm has let us this slide is unacceptable. Before this I have had pmds go out while I was doing 75mph down the high way, and just crap out in the middle of the night and not start in the morning. This was the first full throttle experience I had had with a pmd and it did it while at a stop and a few times while driving down the road. It is dangerous and gm should do something about it.
 
They did. It's called a Duramax :hihi:

Seriously, we've all had this issue since 1994. Somebody even tried to design a new PMD. The only cure has been Bills PMD Isolator, and now there are derivatives.

This issue has kept Steaksauce and Laurence J Kaplan alive for a decade.
 
Hey guys, let's not overlook the obvious while concentrating on the PMD as the culprit. I noticed in his signature that he has a 94. The early MY 94's has a design defect with their APP senders that forced the shut down of the assembly line until the bug was worked out - namely the early units had only two senders and if either one of them went bad (open or short) it would send an unbalanced signal to the PCM that was interpreted as WOT and the PCM would then send a full throttle signal to the IP. GM's cure was to add a third sender to the APP as a fail safe. If you had an intermittent failure of one of the senders that was temperature dependent (you mentioned that you were sitting in traffic at the time ie: heat soak from the crossover pipe to the lower firewall/trans tunnel would warm the APP sensor and cause a bad winding to open) that could be the cause of your problem and throw the code you got, not necessarily the PMD.

My last generation black Stanadyne PMD is mounted to a homemade heat sink (half of a 2hp 3phase motor speed controller heat sink) that is slightly larger than the SSD FSD cooler (but with 22 1" tall fins that gives it a total of 220 square inches of radiating surface) and just lays to the side of the intake manifold on the IP harness "temporarily" for the last four years and 32,000 miles including four nonstop 1,200 mile runs, a six hour run on a 113* day on the Interstate with NO PMD issues.

For peace of mind, if your APP has a two sensor arrangement (two modules attached to the top of the pedal), locate a tested good used '94 1/2 and later 3 sensor unit (new ones are several Benjamins) and swap it out.

Just my two cents worth.
 
Ok here is an update. I received the extension harness from Leroy, thank you very much. And installed my pmd on a fsd heat sink but mounted it behind my drivers head light. I removed the battery and drilled and taped the frame so I could just bolt it up. It is very easy and I believe it will get enough air flow. On top of that it is away from all the heat of the enigine. I will try to post some pictures if I get time
 
You must log in or register to reply here.
Back
Top