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  #1  
Old June 15th, 2007, 20:58
wcbuyer wcbuyer is offline
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4.0L Rough Engine Idle After Restart Following a Hot Soak

What kind of insulating material would be good to wrap the injectors with other then buying the kit from the dealer? I am having this problem and decided that I would wrap all 6 injectors and maybe the fuel rail also instead of just the #3 injector.

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Old June 15th, 2007, 21:09
Shorty Shorty is offline
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Re: 4.0L Rough Engine Idle After Restart Following a Hot Soak

any speed shop can set you up with insulation for engine componants for a little $$$$. I use a foil backed wrap from DEI (not Dale Earnhardt Inc) that's designed for insulating starters from exhaust heat, but only 'cuz it comes in a relatively large sheet and I insulate all kinda stuff between 3 motorcycles, Jeeps, Firebird, Mustang......
--Shorty

P.S. double check that the fuel pressure isn't bleeding off due to leaking injector or bad fuel pump check valve also, as the lower pressure would be more prone to heat soak.
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Old June 16th, 2007, 10:05
wcbuyer wcbuyer is offline
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Re: 4.0L Rough Engine Idle After Restart Following a Hot Soak

Do you think this would do at least as good of a job as the Mopar part:

http://store.summitracing.com/partde...5&autoview=sku

I was planning on doing all 6 injectors.

Thanks
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Old June 18th, 2007, 06:57
wcbuyer wcbuyer is offline
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Re: 4.0L Rough Engine Idle After Restart Following a Hot Soak

Anybody

btt
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  #5  
Old June 18th, 2007, 13:10
Shorty Shorty is offline
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Re: 4.0L Rough Engine Idle After Restart Following a Hot Soak

no experience with it, but it looks like a good price. I would slit the tube and wrap the rail with small cutouts for each injector-- would also try to wrap the injectors if possible. Personally, I wrap the entire assembly as a unit and make small slits for the wires, but that's with the previously mentioned "blanket" from local parts house. I'll see if I can find part number for it as well....
--Shorty
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Old June 18th, 2007, 18:20
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lazyxj lazyxj is offline
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Re: 4.0L Rough Engine Idle After Restart Following a Hot Soak

Looks interesting. My 2001 XJ has the same problem in hot weather or after long hard climbs. It has set off the Check Engine light several times when off-roading.

I have performed the Factory fix of insulating the #3 injector but the problem remains.
I think I may try a piece of this tubing and insulate the entire fuel rail, as suggested.
It would be a cheap experiment
I'm also thinking about a delay relay for the aux fan. It would let the fan run for several minutes after shut down to reduce the heat soak.
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Old June 25th, 2007, 00:36
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yossarian19 yossarian19 is offline
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Re: 4.0L Rough Engine Idle After Restart Following a Hot Soak

I have a 98 4.0 / AW4 that exhibits the same symptoms - so far as I've pinned down, my idle drops low and almost stalls when engine is warm as when coming off the highway / been driving around town for a while continuously. Hasn't happened when cold (yet) - just drops from 750ish to 400ish RPM and sputters back up. No hesitation on acceleration, highway performance is great - just idling it will drop RPM and almost stall before regaining.
So far does this sound like same problem>
I know - I'm supposed to search and see. I did. I'm having trouble with this - everything I know about cars I've learned working at a junkyard... meaning I know how they come apart and nothing about keeping them running well...
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Old June 25th, 2007, 01:02
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casm casm is offline
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Re: 4.0L Rough Engine Idle After Restart Following a Hot Soak

I have the same problem on my 2000. The insulators are sitting on a bookshelf waiting to go in, but I just haven't had the time to do it. The post detailing the TSB procedure, part numbers, etc. can be found here. If it works for you, it's probably the cheapest possible fix - the insulators are only around $6 apiece or so from what I remember.

About the best thing to do in the meantime is to simply let it idle until it clears itself - don't try to rev it, just let it circulate coolant through the head to get the temperature back down. This really sucks in 120degF heat in the desert in the middle of August, but it beats potentially causing greater problems.
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