Crossed jumper cables help

[Csanino]

RWD Chrysler products will (and SOME FWD) loose the idle memory if the battery dies or is disconnected. Try turning the car on and holding the gas down a little to keep it running. After about 5-10 mins of trying that, the idle should start to re-learn it self. if the PCM was "fried" the car wouldn't start... if the battery was fried, it wont start either. If the alternator was fried...it wont charge but the vehicle will still start and run. if the vehicle had to be jumped off, then the battery discharged due to some accessory being left on, or had a dead cell....regardless the vehicle's PCM would have lost the idle settings, so it will stall out if you take your foot off the gas.

-Carlo

 

[MWADE1984]

you definitly fried the batterry when u do that it welds the plates in the battery together and it will no longer hold a charge u need totake that batt back and get a new one and hook it up and after u hook it up disconect thenegitive battery cable and touch the negative cable to the postive battery terminal with the postive cable hooked up. this will clear the static memory in the cpu. after u touch the negitive battery cable to the positive battery post hook it back to the negitive side of the battery and crank the vehicle and let it idle for about 15 mins so it can relearn idle thenu shoud be good... u will still wanna have ur alternator check at ur local repair shop or auto parts store just to be sure u didnt fry it.... just diconecting the battery wont clear the static memory of the cpu u have to do wht i just told u with the battery cable.... i am a mechanic by trade so i am very familiar with this probem..

 

[potenza]

any check engine or other lights on? AZ batteries are not the best sold. You don't buy them you rent them. You may have shorted the IAC but you vehicle does have a relearn.

 

[Snuffy]

I recently bought a pickup and when I went to look at it, the battery was dead. I jumped it but idle was poor and it had a check engine light. I scanned the computer and not surprisingly, it coded Idle Control Circuit Malfunction. After replacing the battery, it would idle correctly and no more check engine light. One of the inputs to the Idle Control Circuit is battery voltage on this vehicle.(Nissan) So...low voltage can affect other "stuff".

Snuffy

 

[Steve-O]

There are a lot of possibilities when it comes to reversing polarity when jump starting a car. I am an ASE certified master tech, I have been under the hood all of my working life, I'm 30 so 15 years now. At my shop, when we see this problem, the first thing my techs or I look for is blown fuses, alternator charging, reserve CCA from the battery and melted wiring. After we get it running and fix any of the previously mentioned problems, we start diagnosing the remaining issues. The previous comment about the idle memory is correct, all cars have a different procedure for relearning idle memory but when the computer looses power, most of the time the adaptive memories go with it. On the jeep, you crank it, give it gas so it will idle, then slowly let your foot off of the gas until it will idle on its own. When it begins to idle by itself, leave it alone for 10 min, that is the time it takes for the idle to reset. If it will not idle on its own no matter what you do then its time to look farther into the system. On stepper motor IAC controlled vehicles the easiest way to test the computer is with an IAC tester. It is a small plug in devise that blinks to let the user know that the computer is trying to control the IAC. Here is a link: http://www.handsontools.com/OTC-3054C-Noid-Lite-IAC-Tester-Set_p_6836.html. This is a noid light kit but the IAC tester is on the lower right. Try to find someone in your area that may have one. If the lights don't blink then the computer is bad, if the lights blink then the IAC is bad. At a minimum, replace the battery, check the alternator and fuses and go from there. If you need any further in depth help email me. Hope that helps some.
Steve

 

[sniperpeeps]

Thanks for the input everybody, here was the solution: Replaced battery (under warranty), cranked jeep. Jeep would fire up and run but not idle, so I just let it rev at 2-3K rpms for 10-15 minutes. Let off of the gas and she purred just like she should. Took her for about a 30 min drive and shes as good as new. Apparantly jeep CPU's have an "idle memory"? and if it the jeep loses power for awhile the computer forgets it and has to relearn it. Or maybe it was just magic, but either way it runs now and its thanks to yall's help!

 

[hbrad3]

Wow! That's pretty cool that all of these members came forward to help a fellow enthusiast. Glad to hear you got the problem fixed!

 

[RIDDLE]

Glad to hear it was something simple.

 

[d2076]

my ex did the same and then I had the same problem. I replaced the battery, wiring harness, and the alternator. After that no problems.........other than she totaled a few weeks later by hitting someone from behind

 

[TBurnham]

Glad it was something simple, and sooo many came forward to help you out.....makes for a GREAT site!!!