Trip from Hell - stalling/bucking

[Rodd]

Okay guy's I posted a couple of months ago about preparing for the hell week trip to my mother in laws. Well hell started before we even got here. Here are the details...

Yesterday my wife called and said she was out of fuel. According to my calculations she should have been able to go another 150 miles or so. I took 5 gal of fuel and my 1/2 gal of power service. I put in the 5 gal and opened the filter housing and poured some ps in and it started up. My wife went 29 miles and called and said she was out again. I had purchased a fuel filter by then and went out and replaced a dark brown filter. Started up w/ 3 cranking cycles. She said it was bucking. I got a new dipacto/dtech pmd last april (installed behind the licence plate in the bumper on heat sink) so I didn't think it was that. I did however borrow a fsd from gmc1999 just in case. I also had 3 other fsd's that semi worked before I replaced them.

Turn the page to today. We left at 6 am this morning and drove almost 400 miles and it started bucking on me and then died. It started right back up then died. I tried all the other pmd's w/ no luck. I got towed into winnamucca Nevada which I was 40 miles past. Lucky me the tow truck that my towing service got me was for a gmc dealer. Just before the guy got to me I thought I would try and start the truck in limp mode. It started. I had him tow me in just to be safe. I called wyatt (gmc1999) and he said it sounded like a pmd issue as well. I talked to the mechanic at the dealership and he said my symptoms are consistant w/ a failing pmd. Unfortunately being in the middle of nowhere they had me by the you know whats. They had 1 pmd in stock for $538 My wife told the guy in so many words that they were crazy. He asked me what I paid for my dipacto and I told him $199. They were generous and took of $100. I swapped them out and drove nearly 400 miles more and it started bucking again when I was about 10 miles from my destination and finally died around the corner from my in laws. Now I need to figure out what is going on. I don't think the new pmd or old pmd is bad since it was about 40 degrees on avg. the entire way. I was thinking my ext cable may have a short but I don't think so. I will inspect that in the morning. Grounds are my next thought. Finally the IP could be the culpret. I don't think there is an ops on a 99. Correct me if I am wrong. We are supposed to leave on Saturday and luckily I brought all my tools w/ me just in case I ran into problems. Oh I have an autoenginutity on my laptop and I tried connecting to my obd2 and my computer wouldn't recognize it. I just got the cable fixed by them in october and only used it once.

Anyone in the Salt Lake City area w/ a scan tool?

Thanks!

 

[Rodd]

Forgot 1 thing. The lift pump is working.

 

[matuva]

Rodd, are you getting power at the cigarette lighter? Check the fuses, it might be blown and could be why your AE scanner don't recognise the truck as the OBD2 connector is not powered.
When she stalls, do you get your lights on at the dash, or off? Wiggle the harness located under the steering colum to see if you can cure/reproduce issue, just to check your ignition switch is not the culprit.
You're right checking the extension, could be it.

Wish you good luck buddy.

 

[Turbine Doc]

You have OPS, but power for the lift in a 99 comes from both the PCM and the OPS you have to lose both to lose the lift's power, easy to check though for power, unplug lift, put meter on pins from main harness key on you should see 12V.

Just behind/below master cyl sticking out of main harness is single jumper red wire black plug, key on & 12V to that plug makes lift run as long as you keep power to it, check filter mgr drain for flow/bubbles.

Sputter/stall sounds like out of fuel issue you said 400 miles 1st time, and 400 miles this time any possibility you have a problem with your tank pickup that at 400 miles, which according to mine is approx half tank for a burb you are sucking air.

Give Bill Heath a call he has some IP diagnostic checks you can do,

 

[Rodd]

Rodd, are you getting power at the cigarette lighter? Check the fuses, it might be blown and could be why your AE scanner don't recognise the truck as the OBD2 connector is not powered.
When she stalls, do you get your lights on at the dash, or off? Wiggle the harness located under the steering colum to see if you can cure/reproduce issue, just to check your ignition switch is not the culprit.
You're right checking the extension, could be it.

Wish you good luck buddy.

That is funny you ask Al. My main cigarette lighter in the center works but to 2 auxillary are not. Those blew out when I was connecting the kids dvd players to the power inverter. Do you know off hand which fuses go to those lighters?

Thanks!

 

[Rodd]

You have OPS, but power for the lift in a 99 comes from both the PCM and the OPS you have to lose both to lose the lift's power, easy to check though for power, unplug lift, put meter on pins from main harness key on you should see 12V.

Just behind/below master cyl sticking out of main harness is single jumper red wire black plug, key on & 12V to that plug makes lift run as long as you keep power to it, check filter mgr drain for flow/bubbles.

Sputter/stall sounds like out of fuel issue you said 400 miles 1st time, and 400 miles this time any possibility you have a problem with your tank pickup that at 400 miles, which according to mine is approx half tank for a burb you are sucking air.

Give Bill Heath a call he has some IP diagnostic checks you can do,

Thanks Tim! I checked for flow through the T valve this morning and it filled 12 oz water bottle to 1/4 in about 15-20 seconds. No air that I could see.

The tank issue I think I resolved a month ago. I bent my fsu down about 1" so it would pick up more from the bottom. IIRC it was about 1 1/2 to 2" off the bottom. I think I bent it so it would be approximately 1/2 - 1 " off the bottom of the bottom of the baffle. The last time my wife ran out of fuel previous to Monday she got 493 miles but she didn't fill up the tank all the way till the pump clicked. Then on Monday she was at 416 miles on a full tank. It could still be it. Pre new fsu I got at least 520 miles to a full tank. It was leaking out when full or sloshed around after I replaced it because the o ring wasn't seated correctly. The leaking is fixed. Also After it cooled down while I was sitting on the side of the road I was able to get it started in limp mode and Idle it for about 5 minutes.

After the tow back and the replacement of the fsd I drove it about 2 miles through town and Filled it up. So I can't imagine the fsu being the problem. Also one other thing, after I filled it up when I was getting on the freeway I got it up to 80 mph and had one buck w/ in 2 minutes of getting on the freeway. I then droped it back down to 70 mph for 100 miles then bumped it up to 75 for about 150 miles and then up to 78 for about 60 or so miles then about 65 - 70 for the last 40 miles or so till it started bucking again.

 

[Dieseldad97]

So I have a friend with a burban that similer issues. Turned out his fuel cap was bad, and his tank actualy imploded to the point of running out of diesel when his guage was just under 1/2 tank. He had to replace cap, tank etc. Fixed.

 

[Rodd]

After checking the tvalve this am, it took 3 cranking cycles and then a puff of white smoke and she started up.

I am going to check the pump relay as Tim suggested what next?

Thanks again guy's.

 

[Rodd]

So I have a friend with a burban that similer issues. Turned out his fuel cap was bad, and his tank actualy imploded to the point of running out of diesel when his guage was just under 1/2 tank. He had to replace cap, tank etc. Fixed.

I have heard of this happening. I will feel around the tank to see if it is disformed in any way. I may have to drop it any way to double check my fsu for depth. This is another plausable problem.

Thanks!

Oh btw diesel dad you have some hot daughters. That is the 2nd or 3rd one that I have seen as an avatar.

 

[Dieseldad97]

I have heard of this happening. I will feel around the tank to see if it is disformed in any way. I may have to drop it any way to double check my fsu for depth. This is another plausable problem.

Thanks!

Oh btw diesel dad you have some hot daughters. That is the 2nd or 3rd one that I have seen as an avatar.

Yeah, it was his fuel pickup that gave him the biggest problem. Funny thing though, when his tank dented it would I guess bend the pickup. Although your problem does sound PMD related...

I like nice wholesome looking girls hehehe...not mine though.

 

[Diesel -T]

Could try making sure to keep tank reasonably full (say no more than a couple hundred miles before fillups). If problem doesnt recurr it may help to zone in on area of problem .

 

[Rodd]

Yeah, it was his fuel pickup that gave him the biggest problem. Funny thing though, when his tank dented it would I guess bend the pickup. Although your problem does sound PMD related...

I like nice wholesome looking girls hehehe...not mine though.

I know mine sounds pmd related. The only thing about the pmd is it's a new one now and it is inside the bumper so it shouldn't be dead. When I felt them both times after it died they were cold.

The other thing I was thinking is I could drive around w/ the cap loose so air can get in.

 

[Rodd]

Let's just say it is the IP starting to fail. Could I run in limp mode for 700 miles?

 

[Dieseldad97]

I know mine sounds pmd related. The only thing about the pmd is it's a new one now and it is inside the bumper so it shouldn't be dead. When I felt them both times after it died they were cold.

The other thing I was thinking is I could drive around w/ the cap loose so air can get in.

The cap can be tested, and are cheap to buy new (10 bucks)

If the tank did implode at all, the damage has already been done to the fuel pickup I'm thinking.

I know it could be many things causing your issues, so take what I have to say with a grain of salt. I'm just trying to help ya. :smile5:

 

[Sunshine]

Please curse me if you will in this time of Thanksgiving for changing the subject, but Gerald, have you see the light again,,, another of your lovely Daughters i pre-zoom..:smile5:

 

[Dieseldad97]

Hey Paul........PM sent hehehe.

 

[Sunshine]

Okay,,, i hope Tim can back me up on this,,,as i can remember rightly he had a problem with Fuel Pump Strainer Sock in the tank, some time ago, & yes, it`s also a suggestive suggestion..

Sorry to hear about Rodd,,, after all to good you have done..

 

[Rodd]

Okay,,, i hope Tim can back me up on this,,,as i can remember rightly he had a problem with Fuel Pump Strainer Sock in the tank, some time ago, & yes, it`s also a suggestive suggestion..

Sorry to hear about Rodd,,, after all to good you have done..

You are speaking of the snotty sock. It is a new fsu as of july/august.

 

[Sunshine]

You are speaking of the snotty sock. It is a new fsu as of july/august.

I didn`t Know it was called that, you`ll have to remember i`m just foreigner..

 

[mfgguru]

There is no way you would drive 400 miles without issue with that stinky snotty sock. Been there, and never got that far. As for the fuel cap, on the other site some other guy almost cold cocked me for saying the tank didn't need to be under negative pressure. The idea was the fuel would foam up at atmosphere and you would suck air. So far, it has never happened. I gutted my fuel cap, meaning I broke out the little relief valve. Never had any issues in almost 100k kms. I'm with school that says your FSU is bent and your not getting your full volume of fuel, especially if it is the same mileage each time.