Possible heat soak issues?

Jeepskate98

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Original poster
Joined
May 28, 2020
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61
Location
South Carolina
My jeep seems to be having an odd problem with warm starts. Starts fine cold but if you drive somewhere and leave it sitting for longer than about two minutes ( ie to pump gas or grab groceries ) it balks when you try to start it back up. While driving the temperature gauge stays well below the 210 degrees midpoint; but if you park and then try to restart the temp gauge will rise to 210 and the engine will splutter until you start moving again. The only way to keep from stalling until you are moving is to rev the engine/ keep your foot on the pedal.
 
The hood gets hot enough to burn your hand and when you open it a rush of hot air blows in your face. Leaving the hood open seems to help with warm starts. From what I’ve read on here these issues seem to be heat soak induced vapor lock.
 
I mention the word 2.5, and all the 4.0 owners out there are like:

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Is there an invisible Casper in this thread that i am not seeing? 😁
 
Have you tried putting a bunch of wood clothes pins on the fuel rail and see if it goes away?
 
I'm glad I found this thread.
Today was the first time I really 'pushed' the cooling system since I bought this Jeep last year. I was driving in hot weather in stop & go traffic with the AC on. I stopped at a store for a couple minutes, and when I restarted the engine it ran like crap and actually backfired when I applied some throttle. After a few minutes it settled down and ran normally. The engine temp gauge was a little above normal.
 
Sometimes in summer if I stop for a short bit like 10 mins or so and then restart. I have to crank longer than normal to get it to restart. Perhaps the recent new starter will resolve that. We will see.
 
Heat soak issues are very irritating. I always had a cylinder 3 misfire after heak soak and ignored it. That is relatively normal with TJ's. I replaced my injectors with new Mopar injectors a few weeks ago for an unrelated issue. It made my heat soak infinity worse. The Jeep barely runs when I start in the heat now. The injectors are getting sent back and I have 6 used injectors coming from a parts lot.

There are steps you can take to mitigate the issue. I would not accept anything much worse than a < 30 second misfire without trying to fix t.
 
Man, that is seriously "old school" stuff, right there. That took me back to vapor lock on my '56 Ford Vicky. Thanks for the memory! ;)

HA! Well it works! If the OP hasn't at least tried it, he's missing out. I have a friend who always has about 12 clothes pins down his fuel rail on his TJ. It solved his issue more then doing expensive heat wrap and shielding.
 
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I had a clogged pre-cat on 4.0 that was getting super hot. replaced my pre-cats and cat and that help immensely with my heat-soak issue. I did install the thermal barrier on the injector, one other thing you can try is running non-ethanol fuel if you can find some.
 
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