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i could not find anything!!!!

kdub41

NAXJA Forum User
Location
hemet
Ok, so i have experienced that on the trail or at higher elevations it seems that my jeep will turn over but once started, it idles quite rough and it really hesitates like its misfiring? and i hooked up an obd2 reader and it said small evap leak and large evap leak. Now when i talked to the gentleman at the place where that was checked he said that this would not make your engine performance any different. is he wrong? and i have checked the forums for rough idle and none of the people are experimenting what i am. so if you guys are gonna get all shitty with me about doing research or what not, then just keep it to yourselves. :D

i just thought that it was wierd that it never does this around town or when it is warmer out :?
 
i have the same issues, when i was up at 13k Feet on one trail i started and it was having a very hard time, my buddy said most 4.0s do it sometimes, has something to do with the map sensor, not sure though
 
yea its weird, its like it doesnt want to go then once you start then it gets a little better then its fine after a few minutes. i wonder if you have to get like a programmable chip to fix this?
 
Did you ever post the exact diagnostic code? I don't feel like reading your other threads on the same issue. Don't assume we know what CEL, or what year, or what axles, or what you've already fixed, etc etc. Details!
 
its a 2000 xj sport, blue paint, grey interior no shifter knob, heater doesnt blow super warm, dana35 and dana30 3.55 gearing 33in. bfg mudders, 4.0 ho, np 231 is that enough info?
 
you really don't need to start a new thread when your answer does not get answered man, there are four of those that start the same way.
 
oh sorry i didnt know that on a forum they had a certain amount of threads allowed lol. I call it being lazy and not wanting to find my other threads that i have posted update that thread. sorry if i have been bugging you guys :wow: next time i will just update an existing thread
 
oh sorry i didnt know that on a forum they had a certain amount of threads allowed lol. I call it being lazy and not wanting to find my other threads that i have posted update that thread. sorry if i have been bugging you guys :wow: next time i will just update an existing thread

No thread limit, but once you start a thread stick with that thread so a logical progression in solving the issue can, hopefully, happen.

That said, your late model (99-01) may be experiencing "heat soak". You are probably just getting your first taste of it when the XJ is good and hot. If not addressed, you will most likely start experiencing it when you stop for fuel or the quickie mart.

Quick test for heat soak, next time you are in a position that should give you the symptoms, as soon as you shut off the engine open the hood and let it cool down that way for about 30 minutes. If it restarts without the symptoms, congratulations you have heat soak.

Search heat soak in the forums. The factory fix is a joke, so don't waste your time with it. Reducing the under hood temperature is the key.

Good luck.
 
i guarantee you that is exactly what is going on because when it does do that its after i have been driving it a while and that makes since.
should i make like a hood scoop type of a deal to release some of that heat?
 
i guarantee you that is exactly what is going on because when it does do that its after i have been driving it a while and that makes since.
should i make like a hood scoop type of a deal to release some of that heat?

Some people raise the rear of the hood with washers/spacers; some cut the hood and install vents; there is (was?) an after market hood with scoop through Quadratech but some reported clearance issues with their wipers; if you have an efan you can wire in a timer to have it run for a set time after the engine shuts off, like this: http://www.at-fairfax.com/P1786-ELK-960.htm

Try searching "hood scoops" and "hood vents", but select advance options and limit the search to "mod tech", some really cool (pun intended) ideas, with pictures.
 
im not sure if its heat soak for me because it has just happened when wheeling, and even then it is only some of the time that it does it, almost seems random, so the cure to heat soak is just to cool the engine down some?

I was under the impression that no matter what every vehicle goes through some kind of heat soak due to the fact that when they shut the motor off coolant stops flowing. It then heats up in the block. Why is heat so so bad in the 4.0?
 
im not sure if its heat soak for me because it has just happened when wheeling, and even then it is only some of the time that it does it, almost seems random, so the cure to heat soak is just to cool the engine down some?

I was under the impression that no matter what every vehicle goes through some kind of heat soak due to the fact that when they shut the motor off coolant stops flowing. It then heats up in the block. Why is heat so so bad in the 4.0?

IF you have a 99-01 XJ with a 4.0, and especially those with the 50-state emissions package (2 pre-CATS in the exhaust manifold), you are at ground zero of a perfect storm of stupid ideas.

THE FOLLOWING IS MY OWN HUMBLE OPINION AND PROBABLY HAS ABSOLUTELY NO BASIS IN FACT:

Stupid idea number one--eliminate the fuel return line from the fuel rail. I'm sure they had their reasons, but every great foul-up has to start somewhere.

Stupid idea number two--they redesigned the manifolds so that more heat comes off the manifolds. They had their reasons for the redesign--more power, stricter emissions standards.

Stupid idea number three--they added the two pre-cats in the exhaust manifold. Again, they had to meet emissions standards.

Stupid idea number four--someone had to see the problem coming, the engineers aren't ignorant, but poor decisions were made. When the problem became so bad it could no longer be ignored they went for the cheap fix--heat shield, switch to NGK plugs, a wrap for injector number 3.

There you go, the perfect storm.
 
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