4.0 Problem

want to wheel

want to wheel

need a rig
Joined
Nov 10, 2011
Location
High Point NC
Hey guys I have a 00 XJ. I took it to URE the first time a few weeks ago. When I parked it on a hill to go help my buddy I would get back in it and start it , then it would start missing really bad I would give it some gas and it would clear up. It did that the hole time but once I got back to outpost if ran great and never did it again. Do these have a external fuel filter?
 
My 2000 TJ 4.0 does that too when I'm trail riding. I've read some stuff on the web about "heat soak", but I've never really tried to do anything to resolve it. After I gas it a couple times, it clears up. Sometimes I'll just choose to let it run if I know I am only going to stop for a couple minutes.
 
I Googled 4.0 heat soak. Here's the Technical Service Bulletin. I have not tried this myself, I just always floor it to clear it out.
NUMBER: 18-031-03
GROUP: Vehicle Performance
DATE: Sep. 05, 2003
THIS BULLETIN SUPERSEDES TECHNICAL SERVICE BULLETIN 18-027-02, DATED SEPTEMBER 06, 2002, WHICH SHOULD BE REMOVED FROM YOUR FILES. THIS IS A COMPLETE REVISION AND NO ASTERISKS HAVE BEEN USED TO HIGHLIGHT REVISIONS.
SUBJECT:
4.0L Rough Engine Idle After Restart Following A Hot Soak
OVERVIEW:
This bulletin involves the installation of a fuel injector insulator sleeve.
MODELS:
2000-2004 (TJ) Wrangler (Domestic and International Markets)
1999-2004 (WJ) Grand Cherokee (Domestic and International Markets)
2001-2004 (WG) Grand Cherokee (International Market)
2000-2001 (XJ) Jeep Cherokee (Domestic and International Markets)
NOTE: This bulletin applies to vehicles equipped with a 4.0L engine (sales code = ERH)
SYMPTOM/CONDITION:
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.
DIAGNOSIS:
1. 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.
REPAIR PROCEDURE:
1. Cut insulator sleeve, p/n 56028371AA, to make two (2) insulator sleeves about 25-30 mm (1 in.) in length.
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).
 

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leave it running .....its prob better for it anyhow
not good to get hot like climbing up a trail in summer then as soon as you get to top shut it off allow the engine to cool itself, leave idleing
 
I did the TSB on my wifes TJ and it worked like a champ. And it's like $6.25 @ the dealership. We used it a lot back when we were seeing a lot of the older 4.0's throught the shop.
 
Hey, thats a real good idea, go to the junk yard and pick up a crappy hood for cheap and chop it up so it'll vent. The hood is no doubt the biggest contributing factor when it comes to a heatsoaked engine bay at slow speed.
 
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