summer time starting problems

When the weather is warm, my 95 XJ will not restart if it is partially cooled down. Once it is almost completly cool it starts and runs fine and if I shut down to gas up or something like that for just a few min. it starts fine. Two trips to Jeep dealers and three other shops have tried to fix it. One shop got it to work for a summer but now it won't downshift on its own.(don't know what they did) New CSP sensor, plugs, wires, distributor guts and computer checked. Any ideas?
Steve

I have a 93' same issue, when the weather gets warm, my XJ acts up. I have replaced so many CPS's it ain't funny.

I did have a situation on the trail last year, everytime the engine got hot, about 210-215 it started to sputter and die. I ended up taking breaks and cracking the hood. I thinking about getting some vents to see if that would make a difference.

Also I had a can of that electrical freezing spray to see if I could pinpoint the sensor. No luck, I sprayed everything. Like always, I lift the hood, wait 10-15 min and then vrooom.

It drives me nuts, hopefully the vents will make a difference.

ChuckD said:

I have a 93' same issue, when the weather gets warm, my XJ acts up. I have replaced so many CPS's it ain't funny.

I did have a situation on the trail last year, everytime the engine got hot, about 210-215 it started to sputter and die. I ended up taking breaks and cracking the hood. I thinking about getting some vents to see if that would make a difference.

Also I had a can of that electrical freezing spray to see if I could pinpoint the sensor. No luck, I sprayed everything. Like always, I lift the hood, wait 10-15 min and then vrooom.

It drives me nuts, hopefully the vents will make a difference.

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I don't know whether it will help with the original post, but for the 93, you might have a problem shared by my stepson's 93 and one other (also a 93) that appeared here: a bad fuel injection wiring harness. What happened on ours (and it took a LONG time and lots of false starts before I figured it out) was that a bad splice to one of the injectors had just enough resistance to heat up gradually, and as it did so the resistance went up just enough to stop that injector from firing. It would often run perfectly until parked, then run badly when restarted and then stay bad. It always ran perfectly cold. I bought an injector and harness tester and it passed all the tests. I replaced a s***load of components, even including the computer, but finally caught it by taking it for a ride and waiting until it misbehaved, then pulling one injector lead at a time. When you pull a good one, the engine will slow briefly, then recover. When you pull a bad one, there is no change. So then I swapped the connection from the bad injector with its nearest neighbor and did the unplug test again to determine whether the injector or the harness was at fault. I found the location of the bad splice finally by testing every wire from the ignition module to each injector plug with an ohmmeter. After weeks and about 200 bucks worth of tuneup parts I had it fixed in 15 minutes with a foot of wire.

So anyway, to cut to the chase, it might be a good idea to find a good wiring diagram and go over your wiring harness with an ohmmeter.

Did it have a spark issue, as far as I can remeber, we had gas at the fuel rail. Passed the injectors I'm not sure, but there was no spark either.

Does that sound familar?

ChuckD said:

Did it have a spark issue, as far as I can remeber, we had gas at the fuel rail. Passed the injectors I'm not sure, but there was no spark either.

Does that sound familar?

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In my case there definitely was no spark issue. I forgot to mention that one of the stages by which I finally tracked it down was running it with a vacuum gauge taped to the rear-view mirror. When it sputtered, the gauge was steady, where I would expect a spark problem to show on the gauge.

I have read that some of the earlier years of Chrysler-era coils were unreliable. I've never had an XJ coil fail, but cutting out when it gets hot is a pretty classic mode of coil failure.

Well I replaced the coil at one summer and my wifes XJ is a 93' also, haven't changed one sensor or coil yet. Mine only has about 25k more than hers. Though that it maybe the coil again , I'm going to try the vents. It only gave me trouble when I was going slow, once I had some air moving, it wasn't an issue. I may just get a coil as a spare just incase.

I plan to replace the coil and I guess I will add some vents. I had also planned to add a control switch for the electric fan so if I'm going in for more than few min. I can turn it on to cool things down quicker after I stop. Or if need be cool things quicker while I'm trying to restart. Thanks for the info.
Steve