Starts and then stalls, need some advice!

[CdnJeeper]

Hello! I just picked up my new to me cherokee and I'm having an issue with it. It drove great on the test drive and on the way home but once at home it wants to stall every time I start it. The previous owner had it for the past 10 years and it is in very good shape overall... my luck this would happen.

Anyway to the point, it's a 1999 cherokee classic, 4.0L automatic, 4dr, pl,pw,ac,cruise etc. It will start and run for a few seconds and then dies. If I hold the gas it will remain running until I take my foot off then it sputters, hiccups and stalls out.

I am thinking it is either an alternator or coil. If anyone has any suggestions that could help I am all ears. Thanks!

[4.3LXJ]

Welcome to the forum

Give me some more details on how it stalls. Like in gear, while moving etc.

[CdnJeeper]

Sure, I was driving the jeep and all of a sudden I lost all power steering, I looked at the gauges and the jeep was off. I tried to start it, it would crank and crank but never start. I could get a faint smell of gas so I assume the pump is working. I let it sit for 15 minutes, tried again, it fired up and ran for 10 seconds (I figured it's good to go) about to buckle up and it sputters and dies again. Except for the first time it happened, all times after have been in Park with the ebrake up.

edit: One time i held the gas when starting it and it remained running until I took my foot off the gas.. then it sputtered and died.

[4.3LXJ]

Might be more than one thing going on here, but the primary problem would be the crank position sensor, located on the bell housing under the intake manifold. Kind of a pain to change, but is a common problem. It is in a harsh environment so it can get a little testy. The next thing I would recommend is removing the idle air control and cleaning it and that should take care of the problem of stalling when just sitting there. And while you are at it I would recommend changing the oxygen sensor located in front of the catalytic converter on the exhaust pipe. Sounds like a lot, but all these things are typically neglected by everyone. None of it is serious. But the Jeep runs by its sensors and they can get a little cranky over time.

[CdnJeeper]

After working on it today, I had it start and run for 15-20 seconds. I thought I had fixed the problem and began cleaning up tools when it sputtered and died.

- I replaced the cap and rotor
- cleaned the battery terminals
- fixed a battery ground that was broken (negative battery terminal to inner fender)
- cleaned the throttle body and IAC
- swapped the fuel pump relay with the starter relay
- checked the condition of the spark plugs
- heard the fuel pump turn on with the ignition
- ran a code reader and found no code, unplugged the CPS and ran code reader, again no codes

Any help is much appreciated.

[4.3LXJ]

Did you unplug the cps and try to start it?

[CdnJeeper]

No I only unplugged the CPS for the code scan. I will try unplugging and starting it tomorrow.

[4.3LXJ]

If yo just unplug it and plug it back in, it will not show a code. All codes, except battery codes, are generated while running or starting.

[CdnJeeper]

If yo just unplug it and plug it back in, it will not show a code. All codes, except battery codes, are generated while running or starting.

Okay, so unplug the CPS and attempt to start the vehicle? I'm assuming it will not start so am I looking to throw a code or what result am I hoping to find/achieve. IE. if i throw a code then the CPS is likely okay?

I will try this when I get home!

[CdnJeeper]

So a big update. I replaced the entire negative terminal and ground to fender cable as both were rotten and falling apart. I found an IAC at the wreckers and cleaned it well before installing it. I had the battery fully charge over night and had it tested, it came back in good condition!

I turned the key and it fired up instantly! I was very happy, i let it sit and idle for 5 minutes while I "again" cleaned up the tools. I sat in it and revved a few times and all sounded great. I took it around the block and ALMOST made it back home when it suddenly died.....

I fired it back up, it ran for mere seconds before dying again. I fired it up again and this time would only stay running when I held the gas. I fired it up and briskly floored it to my house where it died again..

So this is where I am at... I thought I had it all well and working but I am thinking this could be a fuel pump? Any thoughts or help is much welcomed!

[XJ Wheeler]

A bad tps caused that in my brothers '90. Try cleaning it and checking it first.

[CdnJeeper]

Yep I've cleaned the entire TB and the TPS.

Everyone has said CPS from the get go and I believe they are correct. I ran more tests late last night and the jeep fired up.. seconds later it died. I tested for spark at the coil and there was non. Still no codes..

I assume the CPS sends a negative signal to the ECU and won't let me start it again after it dies. Since a bad CPS won't allow the ECU to send spark to the coil I can only assume the crank sensor (the most common failing part) is defective. My coil has a lot of dirt and rust on it so I will replace it anyway just to rule it out.

I have a CPS on order, I will post back letting everyone know the results after installing these new parts. Thanks again for all the help!

[Mudderoy]

Hello! I just picked up my new to me cherokee and I'm having an issue with it. It drove great on the test drive and on the way home but once at home it wants to stall every time I start it. The previous owner had it for the past 10 years and it is in very good shape overall... my luck this would happen.

Anyway to the point, it's a 1999 cherokee classic, 4.0L automatic, 4dr, pl,pw,ac,cruise etc. It will start and run for a few seconds and then dies. If I hold the gas it will remain running until I take my foot off then it sputters, hiccups and stalls out.

I am thinking it is either an alternator or coil. If anyone has any suggestions that could help I am all ears. Thanks!

Ahhhh this sounds like the problem we had with our 99. TPS was bad. If I held the gas petal down a little it would run fine, let off it would die. The TPS controls how opened or closed the butterfly is for idle. I replaced the TPS with an old one that I had and it's running fine now.

We probably need a little more info to be sure that this is the problem though. Nice thing is the TPS is located on the back of the throttle body and really easy to get to, take off, and replace. Seems like they are about $60.

[Mudderoy]

Okay I just read the rest of the posts, yep, that running and dying things sounds like the infamous CPS issue. Check the connection to the harness first, but I bet you'll need that CPS.

[CdnJeeper]

It is alive! Thanks to everyone who replied and bestowed their cherokee knowledge! I swapped in a new crank sensor today and she fired up and idled great. I cautiously drove her around the block hoping she wouldn't stall and she didn't. I am still a skeptic but for now it's running, it's driving and it sounds great.

On a side note, I read a lot of reviews stating how difficult the CPS job was. I used 2 9" extensions, 2 6" extension, 2 u-joints and a 11mm deep socket (if i recall correctly). It was out in less time than it took to assemble all the extensions on my ratchet lol putting it back together i had a friend hold the new one in place while i put the screws in by hand from under the jeep and tightened with the ratchet.

Thank you again.

[jdougn]

You're off to a great start with your XJ! Diagnosing issues like the TPS & CPS aren't real easy but you got it done. Thanks for posting your results!

[weasel]

i am having same problem but mine only starts when ce light comes on i just replaced cps sensor also 20 foot extension and ujoints lol glad you are up and running again

[4.3LXJ]

Checked for codes yet?

[CdnJeeper]

You're off to a great start with your XJ! Diagnosing issues like the TPS & CPS aren't real easy but you got it done. Thanks for posting your results!

Thanks! And happy to do so. Nothing worse than reading threads that randomly end before the OP gives the conclusion :P