rrich

I just looked at mine - an '03 Rubicon, a 05 Rubicon, an 05 TJ, a 95 Cherokee, and 2 94 Cherokees. All with 4.0's.
None have heat wrapping, none have the hot start problem.

I did have a 97 Cherokee with that problem - a new fuel pressure regulator cured it.

So wrap away! Don't forget the pyramid! It's easier than measuring fuel pressure for some. --- (Darn, I forgot the pyramid on the roof on the 97 - should I call him?)

The 2 pre-cat system does create higher underhood temps, but with all the vehicles out there if it was a problem it would be well known.

TSB'S are suggestions - not all are accurate. If it was a problem that wrapping cured - it would have been a recall.

BTW - wrapping - insulating - can hold heat in as well as hold it out. Think about it!

the buddmang

Tsb's are fixes for known issues. RECALLS ARE FOR SAFETy concerns.

djb383

Are there that many vehicles out there where the exhaust and cats r directly below the intake?

the buddmang

Just because yours (or mine) dont exhibit the issue, doesnt mean it's not the fix for his truck.

the buddmang

Depends on the motor, but yes, there are other inline motors with the exhaust/intake on the same side of the head.

the buddmang

My 01 xj exhibited symptons like the heat shield recall, but it was always after long stays in stop and go traffic in 95* and up heat with high humidity. Heat shield corrected the concern, no more misfire after a hotsoak.

Parsnip

I am starting to agree with you both as well as my idea...but in order of what to try id do wrap first - hell its the cheapest and easiest, wngineers do easy stuff first next id check what rrich said, and last and most tediously id try the tps

rrich

As always - don't diagnose it!

Parsnip

Just wrap it in duxt tape, if they cylinders dknt fire just pour in some seafoam and light a match

the buddmang

Just jump on a message board and listen to the guys that work on cars for a hobby in their driveway because theyve helped their uncles cousin's roomate do it lots of times.

Seems to be the going rate, Im just glad I reap the benefits of repairing these internet diagnosing debacles when they bring it in the shop all hacked up...


Fixed and fixed right are two very different things.....

djb383

......exhaust AND 2 cats under the intake? Bet there's not a whole lot of those.

the buddmang

Didnt realize he was being /that/ specific....please forgive me.

77olds

rrich, you need to cool your jets. You're not wrong about the other possible causes, but this specific symptom - a rough idle following a hot soak - is a VERY well known problem with the 4.0, and you sitting there and denying it is like trying to say we didnt land on the moon.

Injector #3 is affected the most. The problem is compounded by old injectors with cracked plastic housings. My heat soak poor idle problem reduced after a fuel injector upgrade and completely went away when I used heat shielding, even after a 3 hour drive on a 90 degree day.

Go ahead and spread your bs about how heat soak/poor idle is a myth. I'll go ahead and stick with the TSB issued and the results I experienced by following the TSB repair procedure.

77olds

Oh yeah and as far as the TPS being suspect, sometimes there are false positives when there's and issue not related to a failed part - the boiled fuel in the injectors is something not accounted for in the programming, so the computer could throw codes for sensors affected by the root problem, while the sensor itself is functioning just fine.

rrich

80 degrees is not really hot.

Federally mandated recalls are for safety reasons. Voluntary recalls are when the mfgr feels a recall would be cheaper than lots of lawsuits and a bad reputation. Voluntary recalls are things like drivability, comfort, and cosmetic complaints.

If he'd actually ever been in the automotive repair business he'd know that.

If you can fix it with candy wrappers and chewing gum, go ahead.
The problem is still there and it will only get worse.
Mickey Mouse repairs like that are the reason the automotive repair business has such a bad reputation.

Using intelligence and logic is a thing of the past. Doing a simple task like measuring fuel pressure is beyond the capability of most "code reader ""mechanics."""

Remember - "basic physics does not apply to Jeeps"