I'm gonna burn this TJ to the MF'in ground.

[JohnJohn]

Who wants to help me burn the MF down?

'98 TJ 4.0 Auto

I've been chasing what I think is heat soak issues for the past month. You know starts and run fine when cold. Drive somewhere go inside for 20 minutes. Come out starts fine, drive 2 blocks and mis-fire and no power for about 30 seconds, roll to Neutral, rev engine, fine for the rest of the drive.


1) plugs, wires, cap, rotor
2) new battery, new battery connections
3) replace TPS
4) round two of plugs, wires, cap rotor
5) pull fuel rail and all injectors, clean and heat shield wrap 3rd injector, replace O-rings and re-install
6) unplug before CAT O2 sensor (RUNS F-IN GREAT)
7) plug in before CAT O2 sensor (HEAT SOAK BACK)
8) drop tank and replace fuel pump/filter/sending unit

So I think the O2 is still good because it's actually doing it's job, adjusting the fuel mix after it reads....when it' un-pluged it just rolls in the open loop setting and does not adjust.

Now I am thinking...
- clogged cat causing heat build up and O2 is adjusting incorrectly
- TJ needs hood vents to let out the heat
- pull all injectors and wrap them, the fuel rail, and all the fuel lines in heat shield tape from the tranny forward.

Any thoughts

 

[in4aride]

Get a heat gun on the cats. We had issue with a customers jeep when I was at ford. Was cats. I'd check that out.


Otherwise.

I am TOTALLY. Down to burn the jeep

 

[Fred]

Have you checked for codes?

What of the above list have you done, as opposed to contemplating doing?

 

[JohnJohn]

No codes tossed, except when I un-plugged the O2. I've done all the numbered things...in that order.

 

[Fred]

Well then, I'd replace the cat, and add hood vents. If you need any help in the pyrrhic fire let me know.

 

[UnlimitedMatt]

The title of this thread is blasphemy!

I agree on the cats. I'm not sure about older tj's but mine has 3 mini-cats.

 

[xj-grin]

fire. fire. he said fire. /beavis/

 

[JohnJohn]

The title of this thread is blasphemy!

I agree on the cats. I'm not sure about older tj's but mine has 3 mini-cats.

I have no Pre-cats just the standard cat and muffler.

 

[old_man]

You can diagnose a clogged CAT with a simple vacuum meter.

Has everybody forgotten how to diagnose a car without a computer?hasta

 

[Digger87xj]

sounds like the typical late model 4.0 heat soak injector issue.

 

[BeastMode]

+1 on the cat.

If not check the evap system (if your jeep has one) could be vapor lock. Might be as simple as the canister or might need a larger fuel rail rather than wrapping all your fuel components.

 

[SolarBell]

FWIW, My heat soak misfire got really bad last summer and the problem ended up being injectors starting to fail. I replaced them with a set of 007's and the problem was gone. Of course your troubleshooting of removing the O2 sensor baffles that all up.

Also I think heat wrap on the injector is pretty much useless. Put a header blanket on and that is actually pretty effective.