1989 Jeep Cherokee Idling, Stalling Problems.

TapouT

Well-Known Member
Joined
Oct 5, 2008
Location
Hickory nc
This is the second thread I've made on this forum so hopefully I'll get some more input. Thanks to all those who tried to help the first time around but this time I'll make it more detailed to try to make things easier. My Jeep has been doing this ever since I bought it back in May of this year. It's a 1989 Jeep Cherokee Pioneer with the 4.0(142,1XX) miles, AW4 Transmission and it's 4X4. Here's what it does...Sometimes when I start it it'll idle wide open like 2500-3000rpm's. I have to shut it off and wait about 10-15 seconds and start it again. It usually takes 1 to 2 times of restarting it to get it to idle back down. Also, when coming to a stop or letting off the gas while driving it starts idling real low and when coming to a stop I have to put it in neutral and rev it up to keep it from stalling. When I put it in neutral and rev it up it idles fine but when I put it in gear the Jeep will jump then fall on its face and idle super low to the point of stalling(this sucks in drive-thru's!!). Then when I drive to give it gas it hesitates for about 1-3 seconds before it'll move. If I don't give it enough gas or if I have to stop it'll shut off...

Example: If I'm at a 4-way intersection and I pull up to a stop sign and there are other cars and they flag me down to go I'll go to give it gas but my Jeep takes a second to get going because it surges and if another car jumps out in front of me to go first and I have to suddenly let off the gas it will stall out.

If I'm out and about and it starts idling real high I usually just pull into a parking lot and spray some carb cleaner in the throttle body with the Jeep off and then start it back up and it idles perfectly fine for awhile unless it shuts off again but I usually pop it in neutral and rev it up before is stalls. Why would spraying carb cleaner in the throttle body make it idle like it's supposed to?

It usually does the high idle thing after it stalls out but not all the time. A guy on here mentioned that it could be the catalytic converter because it was rattling bad but I gutted the cat completely out and it's stopped rattling. I've cleaned the Idle Air Control Valve, cleaned the throttle body, put a brand new air filter in, gutted the cat(it was rattling badly) and I just don't know what's causing this. It also likes doing these things when the Jeep is hot so I'm not sure what that could be but it will also do it when first starting/driving the Jeep for the first time of the day so I'm not sure...PLEASE HELP!! I know there are some Jeep/Renix whizze's out there that can help me fix this bug! ANY and ALL help is VERY MUCH APPRECIATED!! Thank you!!
 
Sounds like throttle position sensor to me. $40 sensor, 5 minute fix.
 
It has a new IAC, also a new TPS; I have also cleaned all my grounds and it is still stalling on me I am also going to put a new fuel pressure regulator on. Does any one have any other thoughts?
 
don't bother with fuel regulator for now...did you adjust the TPS on that...you have to get it right on point otherwise new one won't do much good...TPS on RENIX will give more issues than you would ever imagine so that MUST BE fixed exactly..there are tons of threads with diagrams on proper adjustment..just need voltmeter and patience. do this first before throwing any more parts at it...I've owned many many renix jeeps and that is a #1 problem to start with.
 
also make sure your vacuum line from Map sensor to your Throttle body is secure and not leaking at the Throttle body..they usually from age get very flimsy there and don't seal properly..that's simple fix..another simple fix too is bypass that egr system unless you know for sure it works properly and not leaking in/around it.
 
right now you're hatin the renix system and don't blame you but know this: You have the thickest/toughest/strongest/and most abuse taking 4.0 in any jeep you can find. those first 2years of the renix motors are practically indestructable: twice as thick as 99-05, and bit thicker than the HO too..don't put out as much hp and torque stock as 91 and up but when Properly running and tuned..it will adjust to modifications way better and you can really abuse the crap out them...i ran 3 of mine over 387K miles original with mild rattle to em..buried the temp needle in red zone several times to get one home from wheeling and blew radiator/hoses and on one blew the T-stat housing almost right off the head (huge hole right out the front) running at 300degrees or so..never had issue out of either one..try that in a 91 and up and good luck. shoot i'd trade you my 00 xj motor for yours and do the swap if you were local, lol. these 00s suck for any kind of abuse
 
John Fuller said:
right now you're hatin the renix system and don't blame you but know this: You have the thickest/toughest/strongest/and most abuse taking 4.0 in any jeep you can find. those first 2years of the renix motors are practically indestructable: twice as thick as 99-05, and bit thicker than the HO too..don't put out as much hp and torque stock as 91 and up but when Properly running and tuned..it will adjust to modifications way better and you can really abuse the crap out them...i ran 3 of mine over 387K miles original with mild rattle to em..buried the temp needle in "red zone" several times to get one home from wheeling and blew radiator/hoses and on one blew the T-stat housing almost right off the head (huge hole right out the front) running at 300degrees or so..never had issue out of either one..try that in a 91 and up and good luck. shoot i'd trade you my 00 xj motor for yours and do the swap if you were local, lol. these 00s suck for any kind of abuse
Click to expand...
Where is the " Red Zone"?
 
if you snap the throttle quickly..does it stall on the down idle?(as idle returns to normal) or is it just stalling at random...
 
just to know: cap/rotor button/plugs/wires are good i believe? no vacuum leaks either i hope (especially going to Map sensor? and lastly now with TPS adjusted, does it do it cold or warm and if you snap throttle while idling..does it pop in the intake at all
 
the 2 main causes for this then for my experience on many of these has been TPS and Ignition Control Module (under Ignition Coil). if your TPS is properly adjusted..then try cleaning the contacts on the coil and the module underneath it. That module is around 85 so a little pricey but very worth having a new one anyhow...i'm not making promises over web diagnostics that it will fix it but for me personally these 2 have been the very common issue for this problem. test your map sensor first too..you can test it with ohm meter and vacuum meter. this is about all i can do over the web from the details you have provided. i hope it helps.. keep posted with results as you tinker with it and test things.
 
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