1st Stall in 2 yrs, then drove 150miles no prob

[Matt Bachand]

Going to work today, drove a 1/2 hourish, turned off truck, loaded up, 30 mins later started her up again, and drove another 30 min ride...

Half way there, she stalled while cruising, guages said NOTHING, exceept the Check Throttle light was on, NO OTHERS, without doing anything it 'caught itself' and continued running after about 2 secs of stall. I was able to notice my fuel guage pegged straight down, and when it 'caught itself' it went back to its normal bouncy state.

Grounds I thought, especially FSU ground, where is that??


Decided to take 75miles (each way) road trip to go pick up some new tires so I headed out, right past Aces place and got my new 'used' tires.

Within the first 10 miles of the trip on the turnpike it stalled again, this time it never caught itself, but i tossed it in neutral and cranked it over once and it did. I gave it about 7-10 seconds or so (who knows, time stands still on the highway when a stall happens, lol). I gave it enough time to know it wouldn't catch on its own i felt...

The next 2 hours and 130 miles later, doing 75 at times 2500rpm up hills, letting my 6.5 'clean out' .

No further Stall incident, and topped tank off got 15.9mpg with a few miles of traffic and city driving in there, lots of hills, slight windy day.

I wonder if my PCM fuse is loose? I remember it was blown when I did head repair in winter when starting first time...

Where are all the fuel guage related grounds? FSU ground specifically as my fuel guage is constantly erratic...??

Put a NON DELCO Ignition switch in 2-3 years ago, and it made me think of it, but no wigglieng of key could duplicate the condition...

Any thoughts?

On the good note, got my remaining skins to re-size my tires Saturday hopefully!

Look forward to it, got 4 from a guys 5th wheel camper it turned out, dual axle camper, they in great shape, only one looks 1/2way perhaps, Some old Duramax guy just felt like buying new skins for the 5er due to the 1 in question... 100 bux.

So, for 180bux over the weekend I rounded up 6 better than decent skins, 2 of them beefy beef. Good deal to me.

 

[Edzzed]

sudden unexplained stalling sounds like a pmd. doesn't mean it is though. case in point. when my pmd started faileing i was still able to drive from Vancouver BC to Calgary and back. Then took it to a dealer as the truck was under warranty. they did the ip. and two years later got sudden stalling again. shoulda remote mounted it as the warranty was now up. replaced the pmd under the bumper and has been fine for 3 years. if your stalling gets more frequent or won't start when hot, splash some water on it. simple test but like i said it doesn't always mean pmd. Ed

 

[Matt Bachand]

Agree, Heath unit 2 yrs old (doesn't mean bulletproof), but when it stalled i had NO dash lights at all but the check throttle light.

I remembert that symptom before from ignition switch problem i head years back i want to remember.

Also that fuel guage funky had something to do with it, as that straightenend out and the truck fired up on its own (doing 50mph)...

I'm cleaning fuses, (heath pmd connector, which i UNDID to remove my head) I'll give that the reclean, and try to find this fuel guage ground issue. I'll do this this weekend I hope... works getting busy, got the tire thing i'm hijacking everyones threads with.... and I feel like i'm not spending enough time with my daughter all of a sudden, and I don't like that feeling one bit ...

 

[bk95td]

The fsu grounds should be on the frame rail near the tanks. Checkout the body to frame ground by the downpipe. Also battery to body ground near the batterys. I ran extras with battery cable where they were visable. I'm not real fond of the bare small straps.Redundancy is a good thing. If one fails there still is more.

 

[Matt Bachand]

The fsu grounds should be on the frame rail near the tanks. Checkout the body to frame ground by the downpipe. Also battery to body ground near the batterys. I ran extras with battery cable where they were visable. I'm not real fond of the bare small straps.Redundancy is a good thing. If one fails there still is more.

I replaced my broken strap ground a few years ago with 2 guage batt cable wrapped in aluminum foil to protect it from downpipe 2 years ago.... I'll check that out up close... Actually I just replaced my starter Not even a week ago, perhaps I disturbed it? Perhaps I'll take an old set of jumper cables and go ground silly for free. I really want to find that FSU ground, i've looked many times, and never found it. It doesn't go into a harness and ground through the harness does it? (like the LP does I assume, as its mounted to a plastic piece)

 

[buddy]

I have had the same thing happen before, the mysterious Service Throttle Soon light. and stalling, which would start back up rolling in neutral. That turned into occassional no starts, and somehow the culprit was the fuel shutoff solenoid.

yours being OBD2 and mine OBD1 I dont know that symptoms being similar even mean anything though.

Last time it failed I just took the plunger out, alls it takes is a snap ring pliers and plunger slides right out, and can put it back in.

 

[Brooklyn Tow]

Gotta love GM EFI

Maybe your transistor nuts need a little tweek after 2 years.

 

[vail426]

I can add to the confusion whereas the last time I had a FSD failure, I had a service throttle soon illumination. But, I am OBD 1.

 

[TurboTahoe]

Hmm. This one's tough, Matt.

Most electrical problems are connector related, so I think you are right to examine all grounds and fuses. I have had good experience with a dremel tool with wire brush attachment - and then using DeOxit (Caig Industries) to clean and remove oxidation from all fuses.

I would also check the Heath connector, especially the one from the factory PMD/FSD harness to the Heath-supplied extension cable. I think that the connector is REALLY Mickey-Mouse in quality. I wouldn't be surprised if it is all oxidized and needing cleaning. Personally I would replace Heath's cable with one from Kennedy, but that's another 100 bucks.

Let us know what you find out.

-Rob

 

[Brooklyn Tow]

Leroy's your man for a cable.....100 bux is crazy......on the flip side, there have been a few ext cable failures the last few months.

 

[Matt Bachand]

No time to diagnose anything today, but not a stall....

To be honest, I never liked that heath connector either... But I never had a problem, and like I said it was disconnected back in december.. ...

Shame on me perhaps not to do an yearly ground cleaning, if its not broke, don't fix it is my latest motto after the junk china crank pulley i replaced as preventive maintenance.....

I just need a few months to roll by to get me out of the winter hole i'm in... Damn I miss plowing money.... pray for snow!

 

[96TD]

To be honest, I never liked that heath connector either...

Is it the same one that is pictured in the instructions? The one that really isn't a connector. You just push the pins together and shrink wrap it. If so, then they have updated it since then. When I saw the instructions, I bought one of the connectors so that I could fix it, but when it came, it had a real connector on it, so now I have the connector sitting in a box. Need it?

 

[Matt Bachand]

Was just thinking to myself, if Bill uses it, it must be good, but then I thought if Bill changed it, it must not be.

Perhaps he just wanted to make his kit more plug n play?

If the old setup isn't shrinkwrapped (mine isn't anymore) would that make it corrode up and fail within 6 months?


Truck stalled 3 times in a 15 mile highway run this morning, I noted lights on this time, all lights on dash. Got me double thinking myself that the other day I only saw the Throttle light.... Started right up each time.

I loaded up my materials for the jobs for the day, and wiggled both PMD harnesses and the fuse panel underhood and didn't imitate stall.

Did not stall on the way to both my jobs today.

Stalled once on the 30minute ride home. Started right back up.

Sure does seem like classic PMD issues.

Good ol DS-WHORE!!!!!

Need to get down n dirty this weekend and do ground housecleaning. And track down that damn FSU ground. And have 6 rubbas Mount/Bal'cd....

Good think I enjoy workin on the rig!

 

[Matt Bachand]

Is it the same one that is pictured in the instructions? The one that really isn't a connector. You just push the pins together and shrink wrap it. If so, then they have updated it since then. When I saw the instructions, I bought one of the connectors so that I could fix it, but when it came, it had a real connector on it, so now I have the connector sitting in a box. Need it?

Let me see what this weekend's work results. I will clean up the pins and re-shrinkwrap them and ground cleaning and see where that gets me...

 

[buddy]

Im glad you enjoy working on it too. Youve done some crazy mnx on it, others may have given up on.

 

[Matt Bachand]

All this talk about grounds reminds me of GMCTD... anyone hear from the ol' bugger lately?

 

[96TD]

Was just thinking to myself, if Bill uses it, it must be good, but then I thought if Bill changed it, it must not be.

Perhaps he just wanted to make his kit more plug n play?

If the old setup isn't shrinkwrapped (mine isn't anymore) would that make it corrode up and fail within 6 months?

I'm just guessing at this, but I think that the plug just wasn't available at first. There is no GM plug that for it. It is custom made by Caspers Electronics, and that is what Heath uses now. I'm guessing that when it became available, that is when they switched. Yeah, if the shrink wrap came off of it, and it is exposed, there is a good chance that it has become corroded and could be causing your problem. I wouldn't think that the PMD would fail, but a bad connection could mimick a failure.

 

[Matt Bachand]

Well, I took my heath connecter apart, and the shrink wrap is there, just not 'shrinked tight' its form shaped and slides off easily, so it seems sealed.

The entire connector was still very oily/greasy from the head job, so i pulled it apart, no coorosion whatsoever but oily.

So, I took out all 6 pins, carb cleaned the pins, air blow dried them, and dipped them in di-electric grease, put them in the harness, pulled them back out and re-inserted.

Then started to worry about di-electric grease being conductive. Tested it with a test light on the battery and it seemed to not.

I gooped it up really good inside and out, and under the rubber sleeve/shrink wrap.

Tested it, fired up. I also did the same to the ground wire.

Drove it to fuel up and supermarket (with my 2 1/2 year old, so i'm confident) and no problems.

Time will tell. I didn't want to go ground crazy housekeeping because I want to know where the problem is.

I do remember plowing a slush puddle and it stalled 1 year ago once, but restarted instantly.

If I get another stall, I am going to do the same with the other connector by the heatsync, and take it from there.

Next time my intake is off i'm putting the ground back where it should be on the IP. I know I know.... However, havn't had an issue in 2 years, BUT if my IP to block connection is getting cooroded, that would cause a stall.

Intakes coming off to plumb in fuel pressure guage soon enough, so hopefully stall is gone by then, but experience taught me to plan that it'll come back, lol.

 

[Matt Bachand]

Found one of my FSU grounds (front tank).

Cleaned w/dremel, di-electric grease, and re-install. No change.

I found my other tank's FSU (Burried under 2 inches of muck) on top of rear tank.

My rear tank is plastic (good) must be a replacement. One of the lines going into (or out of) the FSU was rotted right off.

I sure haVe a lot more room under my truck now with the new skins!!!!!! its great.

I also realized that if I drop my driveshaft I will be able to remove my front FSU without dropping my tank!!!!!! To me this is awesome news!!!!

I am going to clean shopvac all that guck on my rear tank and clean it up a bit and try to follow wires. They go into wire loom, and I can't see where it breaks off to ground. I followed the loom about 5 feet past my front tank and past my main LP. Is it possible it grounds via the same bolt as the front FSU?

I'm sure it can't hurt to splice a ground to frame into one of the ground wire of rear FSU.

I assume this is the BLACK wire?? Can anyone verify??

Now thinking about it, I don't remember seeing a harness where the FSU plugs into main wiring (rear tank) Perhaps once I clean up the gunk I'll see more.

The rotted tube sure explains why my rear tank stopped working.

Now i bet my 2ndary LP (rear tank) dry pumped itself to death.

 

[Matt Bachand]

Found the rear FSU connector, burried under the guck.

Lt Blue Wire and Black wire w/white stripe. Which ones ground?

Entire FSU is garbage ... Factory unit for sure. I can replace this one also without dropping the tank!!! Awesome!!!

I literally shopvaced about 10+ lbs of muck off my rear FSU and this u channel about 4 inches deep was flush with guck. Perhaps 20lbs!