Jeep starts and immediately stalls when outside temp is sub-freezing

[wavingpine11]

This actually isn't an issue anymore, but I thought I would describe my symptoms and the fix in case anyone else is experiencing this cold weather problem.

First off, my brother had been borrowing my 98 4.0 AW4 equipped second XJ since last May. I got it back to get it inspected, and have now had it back (keeping it now) since Thanksgiving. My brother said that the battery was in poor shape, and true to his word, if you left the interior lights on for a few minutes, the thing just wouldn't start. So it started poorly in the cold anyway due to not holding a good charge. But then, as of last week, it decided it didn't want to keep running after it started when it was cold out.

Because I knew the battery was on its way out, I wondered if that was part of the problem. However, I noticed that if I started it, then immediately gave it enough throttle to simulate a high idle, and held it there until the vehicle warmed up, then it would generally keep running.

So even though I was concerned about the battery, I also held the idle air control valve suspect. I bought a new one for about $90 at a local parts store, installed it, and the problem has been corrected. The business part of the old valve was covered in soot, but aside from that just looked like the new one.

I was going to add that the thing started and ran fine before it suddenly developed this issue, but now that I'm thinking about it, the idle was actually never very steady before. Even with the vehicle warm.

So the symptoms started as poor idle control, which I didn't pay much attention to, then progressed to an instant stall condition upon starting when cold in the mornings. In the afternoons, after work, it would still start without problem.

I replaced the IAC and the problem was resolved.

--wp11

 

[birchlakeXJ]

Yup, both battery and IAC could create your symptoms. Glad you got it figured out. Oftentimes, cleaning of the IAC with throttle body cleaner restores functionality as well as the stepper motor is still okay, just carboned up.

 

[wavingpine11]

I thought about cleaning it but since I had two possible causes, I wanted to be very sure about eliminating one variable at a time. I still have the old one and was plan ning on cleaning it as you say and keep it as an emergency spare.

I'll buy a new battery soon, but didn't want to do it on the same paycheck, so I'm glad I picked the right one to replace first.

 

[JeepCherokeeGuy99]

I would of def replaced the battery. I had the same symptoms once before and a battery replacement was the way to go. In the future if it happens again, check the volts coming from your alternator with a volt meter. You want to make sure that puppy is puttin out enough juice to the battery. Also, since you live in Philly, i would suggest a battery With a little more CCA. The stock ones just seem so puny to me, especially if it's freezing outside.

 

[wavingpine11]

Jeepcherokeeboy97--

I don't disagree with you. I know that it does need to be replaced, but as I mentionend, I wanted to spend the right money this month to get the Jeep starting reliably again and I do plan on getting a new battery in February.

Can I check the alternator voltage with the battery still connected? Where do I apply the test leads?

And in something that would still fit in the stock batery tray, what would you suggest in a battery? Something like an Optima Yellow Top? I have a Warn M8000 winch that will be going on in the next month or so, so I want to have enough current reserve for that as well.

--wp11

 

[winterbeater]

Check alternator and battery with them connected. Should be about 12.5V with motor not running and 13.5 to 14V with motor running. If it's low when it's running, your alternator is shot. (Slight possibility still though of voltage regulator problem, but not common.) If it's good while running, but too low not running, it's your battery. Don't disconnect the battery while it's running, can blow alternator.

Of course, first you disconnect, polish and reconnect all the connections.

 

[wavingpine11]

Check alternator and battery with them connected. Should be about 12.5V with motor not running and 13.5 to 14V with motor running. If it's low when it's running, your alternator is shot. (Slight possibility still though of voltage regulator problem, but not common.) If it's good while running, but too low not running, it's your battery. Don't disconnect the battery while it's running, can blow alternator.

Of course, first you disconnect, polish and reconnect all the connections.

I'll do that. Thanks for the tip. I just ran into my multimeter the other night. The battery has been disconnected several times recently and no corrosion is evident on the contacts. I'll let you know what I find. I'm assuming the alternator is OK since if the battery hardly starts the car, it gains a little charge from driving it around, but I will check. I like to know as much about the health of this finnicky beast as I can.

 

[JeepCherokeeGuy99]

Jeepcherokeeboy97--

I don't disagree with you. I know that it does need to be replaced, but as I mentionend, I wanted to spend the right money this month to get the Jeep starting reliably again and I do plan on getting a new battery in February.

Can I check the alternator voltage with the battery still connected? Where do I apply the test leads?

And in something that would still fit in the stock batery tray, what would you suggest in a battery? Something like an Optima Yellow Top? I have a Warn M8000 winch that will be going on in the next month or so, so I want to have enough current reserve for that as well.

--wp11

with the jeep running, apply positive test lead to terminal on the alternator itself, the neg goes to ground. The number it puts out will tell you EXACTLY how much voltage the alt is putting out. Testing the battery while running and not running could posibly give you a false indicator of your alt being bad, for example, you may just have corroded cables and or connection. Nobody wants to go buy and replace an alt when its not necessary to.

as for the battery i def recommend optima. They are extremely reliable batteries. Personally I'd get the red top. Isn't the yellow top for marine use? either way, optima is def a safe bet.

 

[winterbeater]

I'll do that. Thanks for the tip. I just ran into my multimeter the other night. The battery has been disconnected several times recently and no corrosion is evident on the contacts. I'll let you know what I find. I'm assuming the alternator is OK since if the battery hardly starts the car, it gains a little charge from driving it around, but I will check. I like to know as much about the health of this finnicky beast as I can.

Assuming is a bad word (ass/u/me). Another key to whether the battery is OK is if it starts up 1 or 2 days after you charge it up with a battery charger. But the alternator isn't recharging it while your driving. (or the cables aren't clean). Somtimes they don't even look bad but aren't really shiny. That's why I polish them with scotchbrite or sandpaper (or my knife in an emergency). But voltmeter checks are better.

 

[joe_peters]

I would like to point out that LIFE, in the context of the modern automobile, begins with the BATTERY.

I congratulate you on having a drivable XJ, but your IAC still might not have been the major issue. A marginal IAC may have been agravated by a marginal battery.

Again, glad your ride is running.

 

[JeepCherokeeGuy99]

I would like to point out that LIFE, in the context of the modern automobile, begins with the BATTERY.

I congratulate you on having a drivable XJ, but your IAC still might not have been the major issue. A marginal IAC may have been agravated by a marginal battery.

Again, glad your ride is running.

X100! well put joe! couldn't have said it any better.

 

[wavingpine11]

I would like to point out that LIFE, in the context of the modern automobile, begins with the BATTERY.

I congratulate you on having a drivable XJ, but your IAC still might not have been the major issue. A marginal IAC may have been agravated by a marginal battery.

Again, glad your ride is running.

And, right you are. I just wanted to split the expenses up between two paychecks. I picked up a yellow top on Friday. Before I did so, I had my flashers going for about 3 minutes after a short drive, and the battery had almost nothing to give. I had to shut off the flashers and wait a few seconds to even get it to turn over once. New battery--no problem starting in 12 F cold over the weekend.

Curiously, the battery was putting out 12.6 V with the vehicle off, and 14.5+ V with the vehicle on. From the voltage readings alone, I could not determine that the battery was bad.

Over the weekend, there were several occasions where the vehicle was left off, and accessories were drawing power, and absolutely no issues with starting again, so between the IAC and the battery, I'm back in business.

Thanks for all the comments and suggestions.

--wp11