Project Heep'n AK
Thread Starter
I make garbage
Joined: Jul 2015
Posts: 420
Likes: 0
From: Alaska
Year: 1992
Model: Cherokee
Engine: Bored over 4.0 with HO performance head
I thought it might be grounds, ended up replacing them all with no luck. Need to find a way to clean up the wiring like running it all to a single control box or something haha, but haven't yet found something of the sort... Still need to do the relearn process for the ECU. It's been flooding itself from what I can tell by how much fuel is on the plugs that isn't being ignited even though I have spark, so I think it's more of an over fueling issue.. Which is why I need to do the relearn
Herp Derp Jerp

Joined: Nov 2011
Posts: 18,251
Likes: 17
From: Parham, ON
Year: 1999
Model: Cherokee
Engine: 4.0L OBD-II
OBD-I PCM isn't going to be flooding itself that much. It would have dumped all of the learned fine-tuning and gone to default mapping when you installed it. Suspect timing or weak spark
Thread Starter
I make garbage
Joined: Jul 2015
Posts: 420
Likes: 0
From: Alaska
Year: 1992
Model: Cherokee
Engine: Bored over 4.0 with HO performance head
Weak spark would still ignite the fuel to an extent though wouldn't it? I mean it may not run like a champ, but in thoery would run.. I've let it sit a few days, tried it and it'll run a few seconds and then die again. But I definitely need to jump into the ignition system testing when I can find a spare hand
Thread Starter
I make garbage
Joined: Jul 2015
Posts: 420
Likes: 0
From: Alaska
Year: 1992
Model: Cherokee
Engine: Bored over 4.0 with HO performance head
Herp Derp Jerp

Joined: Nov 2011
Posts: 18,251
Likes: 17
From: Parham, ON
Year: 1999
Model: Cherokee
Engine: 4.0L OBD-II
Fuel pressure gauge on the test fitting. Or pull entire rail + injectors and watch the spray while cranking.
Thread Starter
I make garbage
Joined: Jul 2015
Posts: 420
Likes: 0
From: Alaska
Year: 1992
Model: Cherokee
Engine: Bored over 4.0 with HO performance head
Sweet thanks! I'll have to test the ignition system when I get the change between work. And I think a fuel pressure gauge is the easier way to go there lol. Thanks again, I'll have to check it out here tomorrow probably
Junior Member
Joined: Nov 2015
Posts: 75
Likes: 0
From: Iowa
Year: 1995,1997
Model: Cherokee
Engine: 4.0
Remove the vac line from the fuel psi regulator, cycle the fuel pump and see if fuel dribbles out of the vac port.
If the regulator is bad it can flood the intake with fuel.
If the regulator is bad it can flood the intake with fuel.
Thread Starter
I make garbage
Joined: Jul 2015
Posts: 420
Likes: 0
From: Alaska
Year: 1992
Model: Cherokee
Engine: Bored over 4.0 with HO performance head
Well since I'm not sure how to upload videos... I can't show you the jeeps running, but after swapping in some performance plugs she fired right up!!
CF Veteran
Joined: Feb 2013
Posts: 1,286
Likes: 2
From: Belton S.C.
Year: 1998
Model: Cherokee
Engine: 4.0
Thread Starter
I make garbage
Joined: Jul 2015
Posts: 420
Likes: 0
From: Alaska
Year: 1992
Model: Cherokee
Engine: Bored over 4.0 with HO performance head
You're telling me haha! Still got some kinks to work out, but she's purring like a kitten. And that's what I was thinking, so I went ahead and upgraded quite a bit over the old oem plugs. Double platinum iridium plugs lol
CF Veteran
Joined: Feb 2013
Posts: 1,286
Likes: 2
From: Belton S.C.
Year: 1998
Model: Cherokee
Engine: 4.0
Glad you finally got it going.
Thread Starter
I make garbage
Joined: Jul 2015
Posts: 420
Likes: 0
From: Alaska
Year: 1992
Model: Cherokee
Engine: Bored over 4.0 with HO performance head
Figured I might aswell with the extra cash I got lying around from house sitting haha. And me to! Now just gotta plumb the temp sensor for the gauge to the one for the ECU so I have a working gauge and bleed my clutch and she's ready for a test


