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been a while - need help, truck died while driving
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Post been a while - need help, truck died while driving 
1998 C3500 CCLB DRW L29 7.4/4L80E/4.10

hey guys, long time no post Razz

heres the deal - my tow rig up and quit on me and i need a direction to start looking before i throw a ton of money at it, or set it on fire (kind of on the fence, lol)

i did a motor swap a while ago (same motor just less miles) left out this morning from Texas to Arizona to go get my Chevelle (moving back to Texas) and about 50 miles from the house it started running rough, but would clear up, like it maybe had bad gas or something.....

it got progressively worse so i decided to turn around and head home. the closer i got to the house, the worse it got - started to miss and pop out the exhaust, but not consistent, and i started to think maybe fuel pump (not even a year old). then i noticed my temp was higher than normal, just over 210 (i have a 160 in it). i stopped by a buddies house to let it cool down a bit, then took off again - about 2 miles from home it started to buck - then acted like someone shut it off, then turned it back on - did this several times, and while looking at the cluster, i noticed my security light came on every time it bucked.....

then, it bucked its last buck and shut off completely and the security light stayed on - put it in neutral and would not crank.... i coasted to the side of the road and that was all she wrote....

will not crank, has power to everything, security light does come on, but shuts off - is not flashing. when i try to crank it i see what looks like the right turn signal coming on (weird right?) ...

no idea where my scanner is so i cant pull codes, but my SES light is not on and yes it is working, lol

just looking for some ideas as to where i need to look first, or if anybody encountered this issue before and what fixed it - i already canceled my trip - so times not a factor, but i need to get it pinpointed so i can fix it....

any help would be awesome, thanks in advance....

Jeff

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Though this isn't the problem with it shutting off, my 98 3500 l29 was running ruff and would clear up I changed about everything and it ended up being the intake gaskets the lower one that seal to the head it's like plastic and was letting water in the cylinder making it miss fire but I never really had to add water, the way I found it was I went to replace the injectors and noticed how dirty the lower plentium was and decided to pull it off and put in my parts washer and when I removed it I found the gaskets bad and the water stains going into the intake runner , put it all back together and no more miss fires , runs great just wish it had more power thought about changing the cam but then I'd have to find someone to tune it and not sure if the heads are big enough to make anymore hp & tq, keep us posted on what you find out so if mine ever shuts off and want start I'll check what you find if I have fuel pressure

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finally got a little time to check things out - charged up a battery and it started up - which raises more questions than answers....

what caused the battery to drain and the truck to die?

the alternator has 14.14v output....

it has a pop through the exhaust at idle, and even when idled up, it gets more pronounced....

i still dont have a scanner to check codes and SES is still not on, i unplugged the MAP sensor and it did trigger the SES - so at least i know thats working, lol

im showing 40-42psi fuel pressure, thought that was low, need to check that - but at least it was steady....

i do have a new alternator on the way, i have 3 laying around im gonna go drop off to get rebuilt into 240 amp units, the one i ordered is a 250amp, going to replace this dead battery as its only a few months old....

still kinda baffling - guess i need to get a scanner and see if any codes.....

gonna try swapping wires, plugs, coil and module with the other motor - just to see if any changes....gonna do 1 thing at a time just to pinpoint it - if it happens to be any of those....

but the whole getting hot and killing the battery has me scratching my head....

oh well, i will update as i figure things out....

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I think you might have more than one problem. The popping that gets worse with RPM sounds like a valve issue, or a misfire issue. Perhaps the distributor gear is going out, as happens on the Vortec engines.

On the electrical issue, my own truck took a turn for the worse. Intermittent shorting, intermittent battery drain, the need to make several attempts to start, eventually became turn the key and shut everything down as though the battery were disconnected. I'm suspecting that the ignition switch failed. I have a new one ready to install on my next day off. Was thinking maybe a failing rectifier bridge since I initially had a slow, intermittent drain but if that were the case it wouldn't be triggered by the ignition switch. Was also thinking maybe a problem with the starter, but even that would at least make some sort of noise when the key is turned. Hoping my list of worsening symptoms might help point you the right way. Electrical problems suck, and my factory manuals didn't even attempt to troubleshoot a problem where turning the key shorts the entire truck out.

I'm about 2 months out from getting a garage up now, and once I do I'm considering building a new truck and sending this one to salvage. I've just had way too many problems with this truck, and have put enough money into it to buy a new truck outright. By now the truck should be problem-free, but the damned thing goes down almost every time I need a truck for something and I'm sick of it.

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update -

took battery and alternator in - both tested good....

bought a scanner - no codes...

still has a pop/miss at idle through the exhaust and reads a steady 40-42psi on fuel.....

im doing the fuel pump next, because if memory serves it should be about 55-58 at idle.... may not solve anything, but i dont like it being that low, once thats done - will see where to turn.... maybe pull the valve covers and see whats going on

im not thinking the distributor gear since theres only 47k on it - but i got a billet distributor i can put in if it comes to that....

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Miles on the distributor is irrelevant, if it's a stock distributor.

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My OEM distributer gear was chewed up just out of the PowerTrain warranty expired at 60,000km(37282miles).
This was on my 1997 rcsb L31, and we had to get the GMs Technical Assistance line involved. They advised to change out the poppet injectors on the misfiring cylinders, so we did 3 new poppets on cyls 3,5,7 or 3, 6,7 but my memory is shady on the exact cylinders. These were the 3 cylinders which were showing exponentially more misfire activity on the Tech 2. After that didn't work, my buddy, a Tech at the dealership, popped out the distributer and realized that the gear was knifeedged. A new gear and all was good again. Must have been one of the first, if GM TAC didn't have a fault tree on it. Surprising since this was on a 97 which was a 2nd year of the L31.
All said and done, that "experiment" cost me about $1000.


[img]https://tse3.mm.bing.net/th?id=OIP.c5-9ePNYPf0YH2Ppq8_afADDEs&pid=15.1[/img]

peace
Hog

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im not against the gear being bad - but its the no codes that bothers me, and also suggests its not misfiring but maybe extra fuel - so maybe some sticking injectors?? and the low fuel pressure doesnt sit well with me either, so fuel pump is definitely going in, then i will do the intake gaskets, and drop in the billet distributor at that point - even if the stock unit is not bad...

got my big alternator in today, looks pretty awesome....

now i need to order a fuel pump, filter, and may as well do the FPR while im at it....

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