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List all of your "heat soak", "hot soak" fixes

garr said:
Has anyone with a late model XJ installed the Hood Vents?

Have they helped with the heat soak problem?
Click to expand...

PM Muddeprived, he installed them with ZERO effect on the heat soak.
 
01xjmeister said:
decided to just remove the aluminum heat shield located between the injectors and manifold Since removing the heat shield the injector vapor lock problem dissapeared.
Click to expand...

You mean this heat shield ?
htshd.jpg
 
garr said:
Has anyone with a late model XJ installed the Hood Vents?

Have they helped with the heat soak problem?
Click to expand...


Just installed some in my 01. Not hot enough around here yet to give em a good workout.

676a0029.jpg


676a0034.jpg


Even on cool mornings there is heat waves rising up from the vents when I stop. Next mod is an aux fan timer if I still get heat soak spasms. :variety:
 
danny Benavidez said:
You mean this heat shield ?
htshd.jpg
Click to expand...

Yeah, thats the POS we were talking about. Looks like they changed it at some point as teh one I had only covered up the center (valley if you will) of the manifold... it looked good at first but then deteriorated quickly.

I installed hood vents on mine, but the heat soak was pretty much taken care of when I went with the earlier style exhaust manifold.
 
i had issues with long crank times after hot shut downs and rough running.

i also have the renix and it turned out that my fuel pressure regulator diapraghm ripped and it leaked gas into the intake mani. after having it running. pull the vacuum line on the FPR and check for gasoline. shouldnt be any there
 
Heat soak causes vapor lock in the fuel rail and is usually combined with, or aggravated by, a slightly leaky fuel injector and/or a failed fuel line pressure check valve.

garr said:
Has anyone with a late model XJ installed the Hood Vents? Have they helped with the heat soak problem?
Click to expand...

Plenty of people have installed Le Baron and other type hood vents. They help lower under-hood and engine running temps, but I still have heat soak/vapor lock probelms.
 
Using heat shields and insulators is a two way street. Once everything is in a stable state, the temperature of the insulated part is the same in and outside the insulation. Then when everything starts cooling down, it remains hot, insulating the part from the cool temperature.

Air flow is everything for a heat shield. It ends up being a heat sink too. It will radiate the temperature it is at as well as absorb the heat impinging on it.

I wouldn't trust FI from a junk yard without testing. When my 90 injectors started leaking, I just bought from FiveO motorsports. They were Bosch and matched with multipe orfaces. So much better in fuel economy and overall performance. They really messed up my emissions in conjunction with the Borla header and exhaust system. Ended up using formally used Splitfires to get it to pass. BTW, Just passed again last week after 4 years.
 
My 2001 XJ has long suffered from the hot soak issues. I installed a fan timer two years ago to help with the problem. It does fine as long as I remember to push the timer button.
This winter, the XJ started idling poorly and doing the hot soak thing even in cooler weather, after long drives..
Pulling off the air intake hose, at the throttle body, I could hear a hissing in the intake manifold, just after turning the engine. That indicated that one of the injectors was leaking.
Got a new set of injectors from FiveO Motorsports and they cured the idle problem and also improved the hot soak problem.
It has already started to get warm here, the right conditions for hot soak problems, and I have not had one incident since. Let's see how it performs when it get HOT.
If you have a hot soak problem, check your injectors for leakage and also check the fuel pressure, seeing how quickly the pressure in the rail drops when the ignition is turned off.
Quickly dropping pressure is a sign that the pressure regulator is going bad or you have an injector leak.
 
n1ywb said:
. Maybe I'll get one. My problem is so intermittent, I'd like to leave one on full time and remote it to the cab. Dunno how safe that is...
Click to expand...

Might be a better idea to leave the pressure gauge outside, taped to the hood. A high pressure fuel line, inside the vhehicle, could cause serous problems if it somehow broke.

BTW, my heat soak problem got progressively worse this year, happening in the winter. I checked the pressure, after turning the engine off, and saw a unusually rapid drop in pressure. Remove the throttle body's intake hose, I would hear a faint hissing, indicating a leaky injector.
A new set of injectors from Five-o Motorsports cured the problem and the XJ has continues to not have the hot soak problems during the last couple of weeks, now that the heat has come to SoCal. I bet it still happens when it finally gets really HOT.
 
Checked my parts catalog...

In 1999, there were no pre-cats. None. Zero. Zilch. Nada. The exhaust manifold had one outlet.

In 2000, they hadn't updated the exhaust manifold picture, but show separate manifolds for front and rear banks. A no-cat downpipe was available for federal and european apps, build date 1/20/2000 is used in various confusing ways. Pre-cats were available but I'm not sure what vehicles they were used on.

In 2001, the pre-cats are 50 state, and the downpipe without them was only available in Europe and for leaded fuel applications.
 
i have 89 and i got it cheep $350 so i was expecting allot of issues biggest one was the cooling system had everything from rotten block plugs to the cap on the pressure bottle would loosen and tighten itself when i say over heat i mean above 230* while running when the engines off its not as big a deal there's no force applied so what i did was removed every thing and replaced it all with the newer to get rid of exploding bottle
parts cost me about 200 when it was done and now the e fan rarely comes on basically what I'm saying if you truck doesn't over heat while the engine is running your cooling system should have very little to do with a hot start issue id look else were
 
I've had the heat soak prob with my '01 for two years now.

I reread the TSB this spring and saw that its more likely to be a problem if you're running gasoline with a high ethanol content.

I did a google search for ethanol free gas and found a web site that lists stations selling ethanol free gas.

I got lucky. There are two stations close to my house.

I started running ethanol free gas back in April and have not had the heat soak problem since, and we're in the middle of a heat wave here in VA.
 
i have a 90 xj with a 4.0 in it and i have the same heat soak issue. Sometime it will go away after a minuet or two but other times it will last 30 min. i hate it but i have not tried to fix it very hard. i have the hood vents in and that doesn't do anything at all. it does let some heat out of the motor compartment but not very much when i park the jeep.

what should fuel pressure be at?
what should running temp be at ?
what parts of the fuel system should i test to see if the need replacing?

please do not put parts in a acronyms please just put the full name of the parts. i dont know abrevations and i hate trying to figure them out.
 
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