96 Grand Cherokee
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CF Veteran
Joined: Aug 2015
Posts: 1,226
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From: Laurium, MI
Year: 1999
Model: Cherokee(XJ)
Engine: 4.0L
Looks like a leaky injector...Unless there's anything else that can make it go super rich at idle and be OK at speed...
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Last edited by rcguymike; Feb 25, 2017 at 01:58 PM.
Thread Starter
CF Veteran
Joined: Aug 2015
Posts: 1,226
Likes: 11
From: Laurium, MI
Year: 1999
Model: Cherokee(XJ)
Engine: 4.0L
No, I don't lick fish.



Joined: Mar 2011
Posts: 11,169
Likes: 26
From: Northern Kentucky
Year: 1999
Model: Cherokee (XJ)
Engine: 4.0
I would check your leaky injector theory first. Thing of it is though, if it is a leaky injector, it will leak all the time. I.E. when you shut it off, it will leak out fuel into the intake plenum. Do you notice if it's hard to start or a lot of black smoke when you first start it?
Thread Starter
CF Veteran
Joined: Aug 2015
Posts: 1,226
Likes: 11
From: Laurium, MI
Year: 1999
Model: Cherokee(XJ)
Engine: 4.0L
I would check your leaky injector theory first. Thing of it is though, if it is a leaky injector, it will leak all the time. I.E. when you shut it off, it will leak out fuel into the intake plenum. Do you notice if it's hard to start or a lot of black smoke when you first start it?
No, I don't lick fish.



Joined: Mar 2011
Posts: 11,169
Likes: 26
From: Northern Kentucky
Year: 1999
Model: Cherokee (XJ)
Engine: 4.0
Try running it for a little bit, then shutting it off for about 5 minutes and starting it up again and see what you get.
Thread Starter
CF Veteran
Joined: Aug 2015
Posts: 1,226
Likes: 11
From: Laurium, MI
Year: 1999
Model: Cherokee(XJ)
Engine: 4.0L
Well, your fuel rail should be holding PSI for quite a while once the Jeep is shut off. So if that's the case, then it would leak down out of the injector rather quickly. Of course, if you're letting it sit overnight before starting it again, most of it may be evaporating out.
Try running it for a little bit, then shutting it off for about 5 minutes and starting it up again and see what you get.
Try running it for a little bit, then shutting it off for about 5 minutes and starting it up again and see what you get.
Edit: and the seller on eBay I got my injectors from is sending me a new set, I just have to send mine back once I swap them. Something I noticed is I don't have the clips that hold them to the fuel rail, should I have those or does it not really matter?
Last edited by rcguymike; Mar 3, 2017 at 08:19 PM.
No, I don't lick fish.



Joined: Mar 2011
Posts: 11,169
Likes: 26
From: Northern Kentucky
Year: 1999
Model: Cherokee (XJ)
Engine: 4.0
Haven't driven it in a while, been working from home helping with the new babe, had to run to town to restock and when I ran into the pharmacy and back out it started seemingly normal. Now that I think about it has lately been shuddering on startup a bit. Occasionally when I first take off from work it'll start accelerating but then as I give it more gas to get up the hill it kinda chokes for a second before taking off.
Edit: and the seller on eBay I got my injectors from is sending me a new set, I just have to send mine back once I swap them. Something I noticed is I don't have the clips that hold them to the fuel rail, should I have those or does it not really matter?
Edit: and the seller on eBay I got my injectors from is sending me a new set, I just have to send mine back once I swap them. Something I noticed is I don't have the clips that hold them to the fuel rail, should I have those or does it not really matter?
Thread Starter
CF Veteran
Joined: Aug 2015
Posts: 1,226
Likes: 11
From: Laurium, MI
Year: 1999
Model: Cherokee(XJ)
Engine: 4.0L
Swapped in my warranty replacement injectors, reset the ECU fuel maps, and did wires, cap and rotor while I was in there.
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Crispy
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Rubs off with finger nail.
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Still reading pretty negative on the long term fuel trim. Do the 4 hole injectors pass much more fuel to make the LTFT go really negative?
Crispy
Rubs off with finger nail.
Still reading pretty negative on the long term fuel trim. Do the 4 hole injectors pass much more fuel to make the LTFT go really negative?
Thread Starter
CF Veteran
Joined: Aug 2015
Posts: 1,226
Likes: 11
From: Laurium, MI
Year: 1999
Model: Cherokee(XJ)
Engine: 4.0L
Also finally got the XJwonders battery cables put on.
Thread Starter
CF Veteran
Joined: Aug 2015
Posts: 1,226
Likes: 11
From: Laurium, MI
Year: 1999
Model: Cherokee(XJ)
Engine: 4.0L
worn down 31's fit...barely. I think the helper struts are bottoming out before the bump stops otherwise they probably wouldn't fit.
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No, I don't lick fish.



Joined: Mar 2011
Posts: 11,169
Likes: 26
From: Northern Kentucky
Year: 1999
Model: Cherokee (XJ)
Engine: 4.0
Get some extended bump stops and you'll be able to fit brand new 31's under there. And if you get a little bit longer shocks, once it hits the bump stop, it will "push" the other side down even further (fulcrum and lever).
Thread Starter
CF Veteran
Joined: Aug 2015
Posts: 1,226
Likes: 11
From: Laurium, MI
Year: 1999
Model: Cherokee(XJ)
Engine: 4.0L
Work has us working some OT so I'm hoping I might be able to afford the long arm yet this spring.
Thread Starter
CF Veteran
Joined: Aug 2015
Posts: 1,226
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From: Laurium, MI
Year: 1999
Model: Cherokee(XJ)
Engine: 4.0L
This is what I did for mine. '97 model siting at 4.5" / 32's / stock flares. No rubbing anywhere. It's a mitered piece of 2x2x0.188 tubing ~ 4.5" Lg, capped with 0.125" plates and welded to my factory leaf retainer plates. My shocks are from my previous 3" lift, I will further exploit my down travel with new shocks once I build upper eyelet mounts for the front and raise my rear lower mounts.











