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03 liberty wont stay running

34K views 10 replies 10 participants last post by  Phatred1  
#1 ·
hello my daughters liberty would not start this morning, it was bitterly cold out.... when i got home i boosted it and it started up but inorder for it to stay running i have to keep my foot on the gas pedal... once i take my foot off the pedal it stalls out.. any ideas??????
 
#3 ·
hey tsukikage, before you changed your iac, did you get any codes that notified you to change? what were some of the symptoms that you ran into before you changed it?

i am running into some issues that may be cause by a faulty iac but i wanted to see what your experience was.
 
#4 ·
no codes at all. it started off as some power loss (mostly over bumps) and then it would perk back up. Gradually, it got worse and more often till it would not idle at all...just die. I had to slip it into neutral at lights and stop signs and give it plenty of gas to keep it running when it finally died on my way to work. I made it back home and replaced it over lunch (I cleaned the throttle body and squirted cleaner into the iac area once prior to the end and that bought me a couple of weeks.)

hope this helps
 
#5 ·
I had a similar issue with my wife's Liberty. I had to literally do a brake torch all the way to the dealer in order to keep it running.

It turned out to be the dead battery. A $195 battery (including $95 service).
 
#6 ·
The Liberty will do strange things when the battery is about to die. Ours could not even keep idle after jump starting it (jump starter was a big SUV). Test it with a voltmeter, anything below 12.6-12.7V could definitely just be the battery. If so, forget about trying to start it, just go grab a Duralast at Autozone (about 90 bucks with core charge). I bet your battery connectors are corrected.
 
#8 ·
I know this thread is old, but it may help someone else out there.

I would recommend changing the battery. My battery was completely dead during a sub-zero cold snap...nothing but clicking relays when I tried to turn it over. I jump started it and it fired right up, but would stall the second I took my foot off the gas. It wouldn't stay running at idle. The problem was immediately fixed by installing a new battery, and there hasn't been a problem since.

Here's my question....why would a bad battery cause a stall, after the engine is running and the alternator is providing power? According to the mechanic at my local Jeep dealership, it could have something to do with the PCM (Powertrain Control Module). He said the PCM loses it's "memory" when the battery is disconnected, so the car may need to run for awhile in order to give the module time to relearn the proper idle settings and reset itself. But the stalling issue went away immediately after installing the new battery. It ran fine at idle right from the get go.

I think something else is going on, but I don't know what. How does a dead battery affect the electrical system when the car is running? How does it affect the PCM? It anyone has an ideas, I sure like to hear them.
 
#9 ·
I know this thread is old, but it may help someone else out there.

I would recommend changing the battery. My battery was completely dead during a sub-zero cold snap...nothing but clicking relays when I tried to turn it over. I jump started it and it fired right up, but would stall the second I took my foot off the gas. It wouldn't stay running at idle. The problem was immediately fixed by installing a new battery, and there hasn't been a problem since.

Here's my question....why would a bad battery cause a stall, after the engine is running and the alternator is providing power? According to the mechanic at my local Jeep dealership, it could have something to do with the PCM (Powertrain Control Module). He said the PCM loses it's "memory" when the battery is disconnected, so the car may need to run for awhile in order to give the module time to relearn the proper idle settings and reset itself. But the stalling issue went away immediately after installing the new battery. It ran fine at idle right from the get go.

I think something else is going on, but I don't know what. How does a dead battery affect the electrical system when the car is running? How does it affect the PCM? It anyone has an ideas, I sure like to hear them.
The Alternator does not have a built in regulator...the PCM provides a varying voltage to the field coil in the alternator to increase/decrease the alternator voltage....if the battery voltage is too low to start with...the PCM dies and cannot provide this field coil voltage.

The older style alternators with a built in regulator are usually "self energizing" in that there is enough residual magnetisim in the alternator field coils to start providing voltage as the rotor is turned....this then feeds back more voltage into the field coils and so on.;)

I believe the 2005/6 CRDs now have the regulators back inside the alternators...the gassers still use the PCM to drive the field coil.:confused:
 
#10 ·
I've been through this with my XJ, after a few miles of feathering the throttle it was fine. It takes a little time for the pcm to correct its parameters. No problems since, that was over a year ago.
 
#11 ·
Need help !

2003 jeep liberty changed alternator and battery as well as a broken rocker arm , replace the idle air contorl valve and car is starting but wont stay on like said in previous comment above i have to keep pressing gas pedal to keep car on.