1991 4.0 manual running rough to wont start

J

JPYJ1991

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Joined
Mar 21, 2024
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2
Location
Cleveland, Ohio
Hi All,

My 1991 has 167K miles. 4" lift, running 35's. I recently acquired and have been going over it and also using a few times over the weekends to take kids to ice cream, baseball, etc... It was running fine but i was having an issue with the temp gauge redlining just after start up. Immediately after there is no way it was over heating. Not wanting to push it, i stopped driving and started to troubleshoot. I have changed out the water pump, serpentine belt, coolant temp sensor, radiator, coolant thermostat and housing... I took it around the block and it started running rough - to the point i knew it was going to die...and unfortunately it has. No coolant in the oil, i'm pretty sure the head gasket is OK. It went from running fine, to running rough, then to barely running and now it won't fire up. As a result i can't check the temp gauge but assume this is fixed. The jeep was previously well maintained but sitting in a garage for the better part of 10 years. I'm thinking it may be a fuel issue...Looking for feedback on where to start.

Thanks!
 
JPYJ1991 said:
Hi All,

My 1991 has 167K miles. 4" lift, running 35's. I recently acquired and have been going over it and also using a few times over the weekends to take kids to ice cream, baseball, etc... It was running fine but i was having an issue with the temp gauge redlining just after start up. Immediately after there is no way it was over heating. Not wanting to push it, i stopped driving and started to troubleshoot. I have changed out the water pump, serpentine belt, coolant temp sensor, radiator, coolant thermostat and housing... I took it around the block and it started running rough - to the point i knew it was going to die...and unfortunately it has. No coolant in the oil, i'm pretty sure the head gasket is OK. It went from running fine, to running rough, then to barely running and now it won't fire up. As a result i can't check the temp gauge but assume this is fixed. The jeep was previously well maintained but sitting in a garage for the better part of 10 years. I'm thinking it may be a fuel issue...Looking for feedback on where to start.

Thanks!
Click to expand...
If it truly wasn’t over heating, why change the parts that you did? When it is running again install a mechanical water temp gauge, at least temporarily. The factory gauges are notorious for being problematic. That doesn’t mean that it can’t be made to work properly if it is faulty. But the mechanical gauge will verify this. As for your running issue, (paging Machoheadgames). The resident 4.0 expert.
 
ytradio said:
If it truly wasn’t over heating, why change the parts that you did? When it is running again install a mechanical water temp gauge, at least temporarily. The factory gauges are notorious for being problematic. That doesn’t mean that it can’t be made to work properly if it is faulty. But the mechanical gauge will verify this. As for your running issue, (paging Machoheadgames). The resident 4.0 expert.
Click to expand...
I read through this when it was posted and I wanted to help but I'm not really sure how to. I was confused by the same thing, if it wasn't overheating I don't know why so many parts were changed to help with cooling. Then for it to randomly just die sounds like something else is going on entirely. All I can suggest with this information is to check fuel pressure, maybe try a new CKP, etc. Changing the cooling parts shouldn't have made any difference on the engine running or dying.
 
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