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illicitdolphin
New User
Aug 24, 2012, 8:57 AM
Post #1 of 2
(2104 views)
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Help!! Truck won't idle
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Okay so 2 mechanics later and I'm about to give up and roll it off a cliff. I've been having some issues with the fuel system. So you'll know everything that has been done and everything it's doing. I'm going to start from the beginning.
So I have a 1995 Chevrolet C2500 5.7L. The truck used to stall out when coming to a stop so we figured it might be time to have a tuneup. We took it and had the oil drained and flushed because apparently someone poured sand in my distributor and oil intake. Bought and rebuilt distributor, new spark plugs/wires and none of that seemed to help. We had our mechanic look at it and he swapped the TB out with a new one and replaced the gaskets/rings/fuel injectors. Also checked for vacuum leaks and found none. Now this is where it starts to get bad. It wouldn't idle unless you rev'ed the engine up for a minute and then would cut off the minute you put it in gear. As for finally being able to pull off, it would hesitate like it was about to stall then the engine would surge and it would take off. As long as the accelerator was being pressed it would drive fine, but the minute you let off the gas it would go to sputtering and acting like it wants to die. Giving it a good flooring would rev the RPMs and it would then again take off. Upon coming to a stop it would sometimes stall and when it did, the minute you crank it back up it would drive fine for a few miles then go back to the same old crap. I decided to jumper the ECM and pull some codes. Upon first inspection I got codes 15,22,33,35,44,66,67,81,82,83. I realized half of those were things we'd checked and never reset so I reset the ECM and pulled these codes 15,44,66,67,81,82,83. We then replaced the ECT sensor because the connecting piece was broken and thought we fixed the problem. However, it did not. We then took off the IAC and cleaned it, and TPS. Now I don't know if we did something wrong or what but now it won't even idle, and when you try to press the gas it makes a weird sucking sound and tries to die, when you release the gas the RPMs go back up and it idles for a few seconds then dies. I reset the ECM and pulled this code: 22, so I know it has something to do with the TPS. But what? And what was causing the problems in the first place? It has no A/C in it, it was removed by the previous owner and as far as the other codes 81,82,83 I have been having this strange problem where when I try to turn the key over sometimes, the light on the PRND123 won't light up and the needles on the meters won't move. Someone told me this could be the ignition switch not being able to supply enough voltage to the transmissions ignition circuit. Please help, I'm at the end of my rope and about ready to call it a day.
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Discretesignals
Ultimate Carjunky
/ Moderator
Aug 24, 2012, 4:04 PM
Post #2 of 2
(2054 views)
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Re: Help!! Truck won't idle
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One pattern failure on those is the part of the ignition switch goes bad and you lose your PRNDL, gauges, and power to the transmission solenoids. The transmission will be stuck in second gear when that happens.
Might want to inspect all your grounds first. The computer ground is on the thermostat housing bolt, so make sure that is clean and tight. Really hard to say what is going on without watching some data stream information. Need to know what the TPS voltage is when the throttle is closed, what the IAC counts are, and what the injector pulse width is being commanded at.
The sucking sound might be the idle air control valve opening up all the way cause the computer is trying to bring the rpm up while the engine is stalling out. The sucking noise can also be a big time vacuum leak, so you might want to make sure the EGR valve isn't hanging open and you don't have one of those throttle body gaskets that get sucked into the intake.
Since we volunteer our time and knowledge, we ask for you to please follow up when a problem is resolved.
(This post was edited by Discretesignals on Aug 24, 2012, 4:05 PM)
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