Stumbling on hot start

[ewander]

I know that the heat shield on top of the intake manifold has been discussed. On closer inspection of mine, it has begun to separate and the innards are beginning to disintegrate. My hard starting after running warm has only recently begun. This recall was done on mine a while back. I just called our dealer and they said the recall is good for the life of the vehicle, so I am going to go in and get a new one and see if that takes care of the problem.

Eric

 

[rstarch345]

2000 Limited, 4.0, NP242, currently in need of a wash.

Here's the problem: sometimes, after stopping for a few minutes with the engine at normal temperature, I'll restart the vehicle and have a really bad stumble that feels like the timing's off. Power surges under acceleration, rough idle, sometimes you can make it misfire if you stomp the accelerator.

It looks like this may be linked to coolant temperature. If I park with the needle on the coolant temperature gauge at 210degF, switch off, and come back a few minutes later, the gauge will be reading above that - usually at or just a hair over the first mark past 210; this leads me to believe that heat from the engine block is transferring back into the coolant. If I let it idle until the temperature is back at 210degF, there's no problem. This is only an issue if the temperature's above 210 when starting.

I'm thinking that the block and/or radiator coolant temperature sensors are having issues, but was wondering if anyone else might have any ideas. The XJ runs fine otherwise, has good coolant (still green after nine months in there), and isn't exhibiting any other odd behaviour.

Your problems have been exactly what my 2K experienced.

First, if you have the recall debris shield installed remove it, it's part of the problem.

Second, this heat soak is an old problem and using this factory SB has resolved it for me and many others. I'm not saying it's the cure all, but I've not had a single problem since doing it.

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 (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 vapour to form within the injector. This in turn may cause a momentary misfire of cylinder #3 until the fuel vapour 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).

 

[hawk_sixsix]

TSB states 1999-2004, but I'm having this exact problem with my '97 XJ. I'll still give this fix a try. Thanks!

 

[Hellbent]

it seems like the newer xj's are more prone to this, but fwiw my recently acquired '96 started having injector heat soak/vapor lock issues, mainly when parking for a few minutes then re-starting immediately after freeway driving. i bought some thermo tec heat insulating sleeving and cut it into sections. i wrapped all the injectors and the fuel rail with the stuff, no more problems.

 

[Ukraine Train]

Does anyone have updates on the situation? My '01 is doing the same thing. Yesterday I was out wheeling and there was another guy with a '97+ that had the problem also. Sounds like I need to check if I had the injector insulator put on.

 

[Michael Boracci]

I started getting the exact problem on my 2000 described here in 2004. Bad stumbling on hot start , misfire on # 3 Cylinder , So I would suspect that it has gotten worse with age. I tried new plugs, new ignition rail, and now that I just went through a whole series of replacements in the cooling system due to a bad water pump which caused a sudden severe overheat, I don't know what the heck is going on.

I will check with the dealer about the recall and procede from there. I never had an underhood heat shield but I do see the foil thing on the intake manifold.

Are there any aftermarket fuel rails available for this system?

 

[YMMV]

Does anyone have updates on the situation? My '01 is doing the same thing. Yesterday I was out wheeling and there was another guy with a '97+ that had the problem also. Sounds like I need to check if I had the injector insulator put on.

I actually fixed my problem. I had both TSB done and neither fixed it. THe cause believe it or not was the fact I had my license plate mounted over my grill and my 2 fogs. They were blocking air flow causing the random misfires when hot/ warm start ups. I relocated my plate and removed the fog lamps. Misfires went away.

 

[tsill]

Just contacted the dealer and he mentioned it is not a recall only a tsb? So i ordered the insulator in the tsb for $5.25 and will let you know how it goes. I have the same heat soak issues. Thought it was a leaky injector first off but now seems to lead to vapor. 5 bucks sounds ok to spend.

 

[WEJOXJ]

I am having a similar issue with my 2k. Idle is semi sporadic on cold start and hot. Started with a P0302-misfire cylinder 2. Fixed and still get this variance with some heat build up.

After all of the reading on this over the past several days, along with some other things, Thinking the 0331 head may very well be playing a part.

Wondering aloud here:
Fuel pump pressure a bit low and causing a lag? Or not enough pressure on injectors?
Partially plugged injectors?
This injector coil/rail is inherently a bad design?
O2 sensor, no code?
Time to do the timing belt?
New head with better casting number?
Simply keep the engine cooler while running?

Here's my plan of attack based upon all of your contributions and others (one at a time, not nec. this order):
Call dealer on recalls
Clean injectors
Clean/check TBS and IAC
Check/replace fuel pump
Check/replace O2 sensors
Install cooler thermostat and thermal tape around header.
Timing belt
New head
New cat

 

[WEJOXJ]

Even though no one seems to be reading this thread so much anymore, I will post this anyway.

Called a local dealership today (yes they want our money, and lots of it). Service guy said it's been a number of things, but didn't mention the coil. Could be the cat, head (cast #), injector, or O2 sensor, it's been hit or miss for them too. I have the recall on the tinfoil deal and will take it in to do that at some point. So he was still a little evasive, trying to get me in, but added some clarity at the same time.