truck won't idle after leaving batt unhooked

scriptedmind · 08-06-2009, 11:20 PM

I've got a question for you guys. This has been bugging me for a while.

In my 2001 donor truck, when i purchased it, it was rolled but you could still crank it and drive it. While i had it parked, i unhooked the battery then came back about 3 weeks later and hooked the battery back up to drive it over to the shop. The truck cranked perfect but wouldn't idle, it would die and i could crank it right back up and hold my foot on the gas and it was fine but if i let off it would choke and die. It did this for about a minute or two and then it was fine, it would idle perfectly and i could kill it and fire it right back up and it would idle fine.

Any time i left it sitting i could come back and crank it right back up and it was fine unless i left the battery unhooked for a long period of time. Do you guys have any idea what would cause this?

My buddy said when he bought his 99 silverado used, the battery was dead at the car lot and they put a new battery in it and cranked it and it did the same thing but never did it again.

This has been bugging the crap out of me for a while. My only guess is that the computer is having to relearn some kind of tolerance, but thats just my guess.

Any help or suggestion is much appreciated.

CODE4LS1 · 08-07-2009, 02:38 AM

Sounds like the PCM is learning the idle again after the battery disconnect. I wouldnt worry about it

fastoyzz · 08-08-2009, 12:34 PM

the pmc is just relearning the idle file it will b fine

bouchee2007 · 08-25-2009, 01:36 PM

not to hijack but i have a 91 with the same problem, today was hte first time its had a battery in it for 2 months. did the pcm idle control go that far back. ?

gmullin · 08-26-2009, 04:41 PM

all its doing is a idle relearn almost every car/truck has to do this if u un hook the battery for a period of time goog thing that its not a dodge beacuse its a half hour of highway driving to relearn idle or every time u let off the gas it will stall

gmullin · 08-26-2009, 04:42 PM

any fuel injected motor has a idle controll

Ed Wright · 08-26-2009, 07:23 PM

Takes longer if the throttle body is gunked up around the throttle blade. Might want to clean it before letting the PCM re-learn.

scriptedmind · 08-26-2009, 07:27 PM

Thanks Ed, it was kinda gunky around there. We cleaned the throttle body before we put the engine in the S10 so maybe that will help.

I figured it was just the PCM leaning but I wanted to just make sure it wasn't the PCM learning a tolerance for a major issue.

Thanks guys

08-06-2009, 11:20 PM	#1
scriptedmind Registered User Age: 23 Join Date: Apr 2007 Posts: 119 Location: Little Rock, Arkansas User is: OffLine	truck won't idle after leaving batt unhooked I've got a question for you guys. This has been bugging me for a while. In my 2001 donor truck, when i purchased it, it was rolled but you could still crank it and drive it. While i had it parked, i unhooked the battery then came back about 3 weeks later and hooked the battery back up to drive it over to the shop. The truck cranked perfect but wouldn't idle, it would die and i could crank it right back up and hold my foot on the gas and it was fine but if i let off it would choke and die. It did this for about a minute or two and then it was fine, it would idle perfectly and i could kill it and fire it right back up and it would idle fine. Any time i left it sitting i could come back and crank it right back up and it was fine unless i left the battery unhooked for a long period of time. Do you guys have any idea what would cause this? My buddy said when he bought his 99 silverado used, the battery was dead at the car lot and they put a new battery in it and cranked it and it did the same thing but never did it again. This has been bugging the crap out of me for a while. My only guess is that the computer is having to relearn some kind of tolerance, but thats just my guess. Any help or suggestion is much appreciated.
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08-07-2009, 02:38 AM	#2
CODE4LS1 Registered User Join Date: Feb 2009 Posts: 301 Location: Issaquah, WA User is: OffLine	Re: truck won't idle after leaving batt unhooked Sounds like the PCM is learning the idle again after the battery disconnect. I wouldnt worry about it
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08-08-2009, 12:34 PM	#3
fastoyzz Registered User Age: 31 Join Date: Jun 2009 Posts: 41 Location: pensacola,fl. User is: OffLine	Re: truck won't idle after leaving batt unhooked the pmc is just relearning the idle file it will b fine
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08-25-2009, 01:36 PM	#4
bouchee2007 local engineer Age: 20 Join Date: Mar 2009 Posts: 204 Location: Berkley Mass User is: OffLine	Re: truck won't idle after leaving batt unhooked not to hijack but i have a 91 with the same problem, today was hte first time its had a battery in it for 2 months. did the pcm idle control go that far back. ?
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08-26-2009, 04:41 PM	#5
gmullin Registered User Age: 20 Join Date: Apr 2009 Posts: 115 Location: User is: OffLine	Re: truck won't idle after leaving batt unhooked all its doing is a idle relearn almost every car/truck has to do this if u un hook the battery for a period of time goog thing that its not a dodge beacuse its a half hour of highway driving to relearn idle or every time u let off the gas it will stall
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08-26-2009, 04:42 PM	#6
gmullin Registered User Age: 20 Join Date: Apr 2009 Posts: 115 Location: User is: OffLine	Re: truck won't idle after leaving batt unhooked any fuel injected motor has a idle controll
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08-26-2009, 07:23 PM	#7
Ed Wright Registered User Join Date: May 2009 Posts: 14 Location: User is: OffLine	Re: truck won't idle after leaving batt unhooked Takes longer if the throttle body is gunked up around the throttle blade. Might want to clean it before letting the PCM re-learn.
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08-26-2009, 07:27 PM	#8
scriptedmind Registered User Age: 23 Join Date: Apr 2007 Posts: 119 Location: Little Rock, Arkansas User is: OffLine	Re: truck won't idle after leaving batt unhooked Thanks Ed, it was kinda gunky around there. We cleaned the throttle body before we put the engine in the S10 so maybe that will help. I figured it was just the PCM leaning but I wanted to just make sure it wasn't the PCM learning a tolerance for a major issue. Thanks guys
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