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#3 injector sleeve question (Heat Soaked Engine)

jeepman121

NAXJA Forum User
Location
Ohio
I've been having rough starts here and there...and i think I narrowed it down to the "Heat Soaked Engine" where everybody is putting the sleeve on the #3 injector....some people were saying this was a fix for the coil pack Jeeps only...not the distributed 4.0's...is this true??
 
Do you mean this?:



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 (from driver’s side of vehicle).
 
yes this...actually I have this exact post printed off at home -someone told me that this isn't a fix for the distributed 4.0's I know it says that its for 99+ but there are 99 xj's without the coil pack so I didn't know if this was a fact or what?
 
supposedly, it only applies to the 99->. however, i've seen quite a few earlier xj's afflicted as well. mine was one of them-a '96. i wrapped all six injectors and haven't had a problem since.
 
I believe in 99 they started with the new injector design, where they were all the skinny (non bulbous) type. I don't know if that had anything to do with the TSB or not, I know my brother's '01 was affected by heat soak something fierce, but my '99 sure hasn't been yet.
 
I have heard varying results as well, but the TSB injector shield fix did work on eliminating the heatsoak stumble on my 99. It's only a few bucks and a few minutes to try it.
 
Adding an aux fan switch sounds like the way to go. Would it help to remove that silver "debris shield" they added? Seems like that holds the heat. Most of the vents seem like they would let in a lot of rain.
 
Hallo Jeepman121. I did it this way on my '92..
You switch the fan with the switch and it goes also by the computer automatically.

see switch in cabin on pic 2 (click)


see the extra relay and fuse: 2 pics.

'92 XJ
 
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