xjforlife

I need some help with a hot start misfire. I know they are normal but today and over the past few weeks it had been really bad. Basically on hot starts I crank it it runs at about 200rpm for a few seconds then it dies. It takes about 2 minutes of starting it and it dying to get it to start. Then when it starts and I drive it it is fine the jeep doesn't throw any codes also smells like gas when it does this. Any help is very much appreciated. It's a 2001 with 165,000 miles on it 2" lift and 31" bfg's

toasterknight

Sounds like heatsoak in the 3&4 injectors. The fuel is vaporizing in the line. Add a heat shield between the fuel supply and intake.

tjwalker

The 2000 and the 2001 are the most susceptible to "heat soak". I agree with toasterknight that this is the likely culprit.

There are lots of threads on this on all of the Jeep forums. Search is your friend here. Some things work, some not so much. Some have installed louvers in the hood and timers on the e-fan to keep them running after turning the engine off to reduce underhood temps.

There is a Jeep TSB that can help with mild heat soak. Not saying it is going to cure yours, but it might be a place for you to start.
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TSB 1803103 - 4.0L ROUGH ENGINE IDLE AFTER RESTART FOLLOWING A HOT SOAK
Date: 09/05/03 (supercedes 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 (90ºF) 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.

xjforlife

I'm gonna need to do something to get the temprature down the thing runs really hot the gauge says its fine I'm gonna be getting new headers and pre-cats along with injectors I'll try and make a heat sheild for the injectors I also noticed the feul line runs right past the hot pre cats I'm probably going to rerout it to the other side of the engine

toasterknight

Give a temp for what you consider really hot. These typically run at 210. You have the weaker head so if it was running all that hot it would probably crack before too long. The precats were moved too far into the engine bay causing a heat buildup when the engine is shut off.

xjforlife

It is running around 215 degrees and the radiator is only a year old

toasterknight

You have another issue in your cooling system. Check the fan clutch and may need a water pump if it hasn't been done yet.