01 hot start problem

My 01 4.0 idles very rough and not accerate after heat soak sometimes. It dont always do it. Cannot see any black smoke but it acts flooded, have to feathering throttle to get it to cleaned out. After it clears out it runs fine. It is getting worse. Dont get check engine light. Has any one else had this trouble??

There's a TSB about this problem and I believe it relates to having heat shields fitted over the injectors to prevent fuel vapour forming inside them. Check it out with your stealership.

I just looked on Alldata and I'm not seeing it. My ZJ does the same... low power when hot.

Here ya go: :cheers:

TSB 1803103 - 4.0L ROUGH ENGINE IDLE AFTER RESTART FOLLOWING A HOT SOAK
Date: 09/05/03 (supersedes 1802702 dated 09/06/02)

Model Year(s): 1999-2004

Description: NOTE: This bulletin applies to vehicles equipped with a 4.0L engine. This bulletin involves the installation of a fuel injector insulator sleeve.

Details: Customers may describe a 20 to 30 second rough idle following the restart of a heat soaked engine. This condition may be most noticeable when the engine is restarted following a prior 10 to 20 minute heat soak in hot ambient conditions of approximately 32 C (90*F) or higher. This condition may be consistent with short city stop-and-go driving trips and can be aggravated by the use of fuel with a high ethanol content. Depending upon various conditions a MIL may occur due to DTC P0303 - Cylinder #3 Misfire.

This condition may be caused by heat from the exhaust manifold that following engine shut down migrates to the area around injector #3 and causes fuel vapor to form within the injector. This in turn may cause a momentary misfire of cylinder #3 until the fuel vapor is cleared of injector #3. The insulator sleeve lowers the injector #3 temperature to a point below which the fuel will not normally vaporize.

If vehicle exhibits a rough idle, and if a misfire of cylinder #3 is observed following a 10 to 20 minute hot soak, perform the Repair Procedure.

Parts required:
56028371AA Ignition Wire Shield

Repair procedure:
1. Cut insulator sleeve, p/n 56028371AA, to make two (2) insulator sleeves about 25-30 mm (1 in.) in length. See diagram.
2. Install one sleeve around injector #3, with the slit on the upward facing side of the injector. Install the other sleeve with the slit on the downward facing side of the injector.
3. Confirm sleeve is flush to intake manifold surface around injector.
4. Check injector #3 wire and ensure that the injector is rotated to a 2 o'clock position (from driver's side of vehicle).



This applies for all '99+ 4.0 engines, not just the WJ.

Man this is too funny! I have the same problem with my '98. I've had the problem since new. I found when I was trying to find a solution to this problem. I never did find a fix but I always thought it was vapor lock of some sort. After all this time I think I've finally found the solution.

While it was under warranty the dealer kept saying they couldn't duplicate the problem so they couldn't fix it. In the Milwaukee area we use ethanol in the reformulated fuel so this furthers my belief that this is my problem.

I'll have to wrap up my injectors with some heat tape and see if it finally goes away.

B-loose

B-loose

FWIW, I did the procedure as recommended in the TSB on my '00. It didn't make that big of a difference and the pieces of insulation have since blown away. Pretty cheesy "fix" if you ask me.

Thanks for the info I had read the TSB early in the summer and just wraped some insulation around it. I must need to order the insulator sleeve per to TSB thanks again...

There is also a software upgrade to the CPU which should accompany the heat shield. My dealer covered this one for me since the first repair was done without the software and failed to prevent a repeat one month later. It's been a year and no problems since.

And I too think that the lousy gas we get around here does not help things much either.

I've got a similar problem with my 01. I get the #3 misfire code, but it doesn't seem to matter if it's hot/cold/whatever. The first time I got it, I changed the plugs and got the code cleared and it was fine. Same thing for the second time, but that was just a month and a half ago and I know my plugs aren't shot yet. I'm starting to think bad injector or bad coil, but I'm not familiar enough with the ignitions on these. Gimme an LT1 F-Body and I'll figure it all out, but I'm still learning on my Jeep.

Any thoughts?

steve01XJ said:

And I too think that the lousy gas we get around here does not help things much either.

Click to expand...

Ha!

I've had this problem THREE TIMES. All on the same trip. Running for five hours on the PA tpke, then pull into the hotel in Philly. Jeep doesn't want to start/run when I'm done checking in, carting bags, etc.

Behaves fine all weekend.

Then, drive home. Stop near H'burg for fuel. Doesn't wanna start after fuel stop. Then, stop for quick food/pee break a few hours later. Doesn't want to start.

The common thread? Two fuel stops at Sunocos on the turnpike. Haven't had the problem in nine months since.

Friends don't let friends buy Sunoco....

Den