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coreyt
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Nov 11, 2011, 1:30 PM
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chevy wont stay running
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I have a 2000 Chevy 1500 with a 4.3L. Has @ 100,000 miles. Truck was running great until a few weeks ago when it started misfiring while driving down the road. Got bad enough to where I would have to pull over on the side of the road and restart the truck and rev the engine up all the way to get it to go. I have checked fuel pressure. It's 50 psi. I put a scanner on it and replaced everything the codes told me to. I have put fuel treatment in it and NOTHING!! It will crank and will run for around 3-5 minutes and die as if someone reached in there and turned the key off. PLEASE HELP ME!!
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Hammer Time
Ultimate Carjunky
/ Moderator
Nov 11, 2011, 1:33 PM
Post #2 of 20
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Re: chevy wont stay running
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Your fuel pressure is too low. Replace the fuel pump.
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We offer help in answering questions, clarifying things or giving advice but we are not a substitute for an on-site inspection by a professional.
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coreyt
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Nov 11, 2011, 3:24 PM
Post #3 of 20
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Re: chevy wont stay running
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that was with it running. when i shut the truck off it never faultered. does that matter??
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Hammer Time
Ultimate Carjunky
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Nov 11, 2011, 3:47 PM
Post #4 of 20
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Re: chevy wont stay running
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None of that matters. That engine requires a minimum of 55PSI at all times and usually more.
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We offer help in answering questions, clarifying things or giving advice but we are not a substitute for an on-site inspection by a professional.
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coreyt
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Nov 11, 2011, 3:52 PM
Post #5 of 20
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Re: chevy wont stay running
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ok well after your last post I went out there and put the gauge back on just to double check myself. With keyon/engineoff it is running 60 psi. I turned the engine on and it lowered to 55 psi and when I accelerated the truck it would raise to 57 psi
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coreyt
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Nov 11, 2011, 6:02 PM
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Re: chevy wont stay running
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Ok I understand what a scanner reads. But for every code it read out I fixed. It's no longer reading codes. Yet it still will not stay running
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coreyt
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Nov 11, 2011, 6:21 PM
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Re: chevy wont stay running
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Original codes were bank one lean, MAF voltage high, map sensor voltage high, two o2 sensor codes. Im not at home right now but I have them wrote down at home. Fuel pressure is for sure 60psi with engine off and 55 to 56psi at idle. Like I said it will idle fine for a min then just shut off. If i try to drive it it will missfire, backfire, and stall.
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Sidom
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Nov 11, 2011, 8:33 PM
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Re: chevy wont stay running
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Ok,,,As long as the pressure is at 60psi & holds with key off, it should be good. If need be you can check volume later...
As bad as you describe I'm surprised there is no misfire codes or something. How long have you run it since you cleared it?
I'm assuming you don't have a scope, so you may want to pop the dist cap off & do a visual inspection & look everything else over real good to see if any thing visual pops up....
(This post was edited by Sidom on Nov 11, 2011, 8:34 PM)
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coreyt
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Nov 11, 2011, 8:43 PM
Post #11 of 20
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Re: chevy wont stay running
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I forgot to mention it does not miss at idle, only under a load. Its been almost two weeks since the codes were cleared. There wasn't any missfire codes then either. I've had the distributor cap off to look and check for excessive play on the dis gear. Nothing looked like the culprit.
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Sidom
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Nov 11, 2011, 8:48 PM
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Re: chevy wont stay running
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Does your scanner have the ability to record & save data? If so, a data stream of when it's running good & when it's missing would be helpful... Also if you can access misfire history, take a look at that....
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coreyt
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Nov 12, 2011, 8:45 AM
Post #13 of 20
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Re: chevy wont stay running
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Missfire history codes were at zero. Tried to watch it live and make it miss but missfire counters stayed at zero. I don't think the scanner I have will record data but ill check again.
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Sidom
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Nov 12, 2011, 10:27 AM
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Re: chevy wont stay running
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You know this is a tough one with out much data that we can look at.....I'm drawing a blank right now...
If you are looking at a live misfire counter and it's staying at zero when it's cutting out, I would probably start looking in the electrical area. But this is something I would really want to drive and feel myself.....
Lack of fuel will feels different than something shorting but both can cause bucking & cutting out......
(This post was edited by Sidom on Nov 12, 2011, 10:27 AM)
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Discretesignals
Ultimate Carjunky
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Nov 12, 2011, 10:40 AM
Post #15 of 20
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Re: chevy wont stay running
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Maybe the crank angle relearn hasn't been performed, so the misfire counter is disabled. (just a guess)
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 Nov 12, 2011, 10:44 AM)
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coreyt
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Nov 12, 2011, 11:56 AM
Post #16 of 20
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Re: chevy wont stay running
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I know what you mean. I am an ase certified tech with about 8 years experience and thiis truck is testing my limits. I did the cam/crank correlation relearn several days ago. When I pulled the dist cap I noticed the cam sensor was kinda lose. Even tho there was no code for the cam I thought what the hell ill replace it. Did the relearn after that and still no fix. I've got a feeling its electrical. Im gonna try to take some jumper cables and use for more grounds when I get home. I've heard of some of these trucks having grounding issues.
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Sidom
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Nov 12, 2011, 1:16 PM
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Re: chevy wont stay running
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If you have a good tester coil lying around, throw that on & take if for a spin.........
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coreyt
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Nov 12, 2011, 1:50 PM
Post #18 of 20
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Re: chevy wont stay running
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I don't have a tester coil laying around but I have a friend that might. Im gonna try that and the jumper cable trick and see what happens. I'll let you guys know the result as soon as I do.
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coreyt
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Nov 19, 2011, 3:32 PM
Post #19 of 20
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Re: chevy wont stay running
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 Well I finally got some good news guys. I had a friend come over who's been an auto tech for years. I guess it was a new perspective on it. We started looking at loose wires and bad grounds. The jumpercable trick yielded no change. While the truck was running he barely touched the connector on the coil and the truck died. I tried to restart it several times with no luck. He touched it agian and the truck fired right up. Upon further inspection it looks like somebody shaved a lil bit of the wire insulation off to test instead of back probing the connector. My whole problem was a bad connection on that wire.
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Sidom
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Nov 19, 2011, 3:52 PM
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Re: chevy wont stay running
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Glad to hear you got it going.............It's unfortunate that bad testing methods can actually cause problems of their own down the road...
Thx 4 taking the time to let us know what you found....
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