XJ Quitting when HOT? ? ?

cherokee_kid_03

cherokee_kid_03

Rock Corps 4x4
Joined
Sep 21, 2009
Location
Marion, NC
I have a 1997 XJ with 4.0 I6. It is strictly a trail rig. I have 2 fans that run all the time and on the trail the jeep will reach 220-240 degrees very quick. All my fluids check out and no leaks. When the HEEP reaches 240-250 it shuts off and will not crank back for at least an hour. It will turn over and the fuel pump kicks on when I turn ignition but it does not prime the fuel rail. Usually happens when I am on an incline but this weekend it happened on flat ground. Fuel Pump? Crank Position Sensor? Throtle Position Sensor? Has anyone else had this problem and how is it fixed. I am having the radiator flushed this week, and replacing thermostat, so we will see how that works.:driver:
 
when replacing the thermostat be sure to get a lower temp thermo.. i believe they offer 3 different ones for xj
 
I had some running hot issues with mine a while back. the coolant looked fine but when i did a garden hose flush on the whole system I found alot of brown sludge in the radiator. Once it started flowing out the bottom clear i put it back together and removed the t-stat completely. I've been running no thermostat now for over a year and it never runs hot anymore. Something worth trying. Not sure about the not starting thing. Something i'd have to do some research on.
 
gboroxj said:
if its just a trail rig and you dont need heat just take out the thermostat and it should not heat up at all
Click to expand...

unless there is something wrong with the system, plugged, bad water pump, headgasket leak etc.
A thermostat is really more of a temperature regulator. It has nothing to do with how hot it will run, only how cold it will let it get to. If it is getting to 240* then switching from a 195 t-stat to a 160* one isn't gonna do a thing unless the current one is sticking shut, in which case just replacing it with a new 195 would do just the same. If the thermostat opens fully and the jeep still overheats, you have a different problem than the thermostat.
FWIW, I run a 180* t-stat in my 4.6L stroked ZJ, and on the trails I've seen it reach at the max about 215*

I don't remember what years ran what cooling system, but is your model a closed loop system or open loop.
 
thanks for all the info. . . Going to try and work on it this thur and friday
 
When this happens do you have pressure on the fuel rail?

Also agree, if you still have all stock cooling parts it's time to replace. The changes to teh system ie. not thermostat etc are just bandaids to a cooling problem. Find the problem and fix it. Don't fool it into running cooler.

My system runs at 210 all the time. Runs great.

If you run it too cool it will run rich.

***edit read your whole post about fuel rail***

If it's running hot it could boil the fuel in the rail, this would make an air bubble. Work on the cooling.
 
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***edit read your whole post about fuel rail***
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So did I miss something on the fuel rail? I
 
Mine ran hot at the last ECORS race..I was just starting to panic when all of a sudden the temp dropped back down. So I thought It was fine and I didnt go to the pits. One lap later it overheated again and shut off. We waited about 25 30 mins for some water..poured it in and she fired right up.

I still have to check into that..thanks for reminding me.
 
Dylan W. said:
Mine ran hot at the last ECORS race..I was just starting to panic when all of a sudden the temp dropped back down. So I thought It was fine and I didnt go to the pits. One lap later it overheated again and shut off. We waited about 25 30 mins for some water..poured it in and she fired right up.
I still have to check into that..thanks for reminding me.
Click to expand...

We need a flush kit, refill and a new tstat. Its on the list man:lol:
 
cherokee_kid_03 said:
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***edit read your whole post about fuel rail***
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So did I miss something on the fuel rail? I
Click to expand...

If you're asking me the fuel rail is next to the exhaust. Alot of heat naturally radiates towards the rail. It's not a big deal, unless the jeep is running hot, which yours is. You need to fix your cooling system first. Also it could be a bad regulator that when it gets hot it allows the fuel to pass. Put a gauge on the rail and see what the pressure is, both hot and cold. Also at starting and running. Also does the pressure blead down? It's OK to leave the gauge hooked up, just make sure it is out of the way of any heat and moving parts.
 
Had a similar issue a few years ago. I had routed the exhaust too close to the frame rail fuel line routing. When the fuel lines got to a certain temp it would start to run like crap or cut off and not start until it cooled. Reroute of exhaust fixed my problem.
 
Also it could be a bad regulator that when it gets hot it allows the fuel to pass.

Which regulator are you talking about?
 
I had an overheating issue for awhile on mine. It needed a flush badly and my electric fan was also overheating. Start with the flush and when it starts overheating check to make sure all the fans are still running. Stupid electric fan was cutting out when it got hot but worked fine if you tested it in the garage.

New fan and a flush and I run at 210 all day on trails with the AC running with mostly original parts.
 
Thanks for all the info eveyone. I am getting a couple days off work this week so hopefully i can get a flush and change some stuff under the hood. . .
 
Yeah its the orig rad. . .140K miles. After a flush if that is not the fix I need I will replace the Radiator
 
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