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Heat soak misfires but getting much worse.

SeansBlueXJ

NAXJA Forum User
So I am fimilar with the #3 misfire on a heat soak issue always had it. I could always throttle through it and get past the issue. But it was only on really hot days (90° or more). Now here lately it's after every trip and sometimes so bad that I need to try 3 or 4 times just to get it to start.... Any experience or though on this? Cold start is just fine...
 
Have you done the tsb? What year is your jeep?
 
I would start with the DEI insulation/shield kit to see if that helps.
 
Have you tested the fuel pressure, and confirmed that the fuel pump assembly check valve is holding pressure after shut down ?

Installing an ELK-960 e-fan timer module seems to be the best solution. http://www.naxja.org/forum/showthread.php?t=1045030
 
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For about a year, I had hard starting issues with the engine warm. Replaced all kinds of parts and still the issue got worse. Eventually it would take three long cranks to start when warm and even a long crank when cold. Replacing my fuel injectors solved the problem instantly. It starts up every time now, like a light switch.
 
Done the TSB years ago. It's a 2000 XJ.

Have you tested the fuel pressure, and confirmed that the fuel pump assembly check valve is holding pressure after shut down ?

Installing an ELK-960 e-fan timer module seems to be the best solution. http://www.naxja.org/forum/showthread.php?t=1045030

While no pressure test I'm going to say that it's holding. If I turn the vehicle off for a long time. (Overnight, while at work) no issues. But if it's an off/on type deal it's gotten way worse then the standard TSB symptoms I have had forever.
 
.... If I turn the vehicle off for a long time. (Overnight, while at work) no issues.

The e-fan timer should reduce or eliminate the heat soak symptoms. One might also suspect a drippy injector or two.
 
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