Running rich, but code says too lean?
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Joined: May 2012
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From: Lost in the wilds of Virginia
Year: 1998 Classic (I'll get it running soon....) and 02 Grand
Model: Cherokee (XJ)
Engine: 4.0
I have wondered that myself. That's one of the reasons I'm replacing the rail and injectors. I can't afford the time to keep fiddling around with this, and at 6-8 MPG, I'm burning a lot of cash with this problem, not to mention how bad this is for the engine.
The service manager suggested taking a close look at the cat, too, which I will do. It could very well be trashed by now.
I'm out of town at the moment, so won't get to this until next weekend. By then the parts should have arrived, and I can hit this next Saturday.
One thing I'm worried about is the fuel line connector being so rusted it won't come apart, or go back together properly.
I'll be replacing the rotor & cap, too, as they are in bad shape, even though they are new. Probably a result of high resistance due to the super-rich environment.
All that and an oil change is on the schedule for next week.
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CF Veteran




Joined: May 2012
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From: Lost in the wilds of Virginia
Year: 1998 Classic (I'll get it running soon....) and 02 Grand
Model: Cherokee (XJ)
Engine: 4.0
Well, nary a word from Programbo, so I've found another source for injectors.
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Joined: Aug 2010
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From: Canton, MI
Year: 1999
Model: Cherokee
Engine: 4.0
Rust on the outside is cosmetic.
Use the proper 5/16" releae tool. Advance auto has a good one. It's Red in color. Don't get that Aluminum colored cheap scissor-like tool.
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CF Veteran




Joined: May 2012
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From: Lost in the wilds of Virginia
Year: 1998 Classic (I'll get it running soon....) and 02 Grand
Model: Cherokee (XJ)
Engine: 4.0
Depends how deep it is!

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Joined: Aug 2010
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From: Canton, MI
Year: 1999
Model: Cherokee
Engine: 4.0
Thread Starter
CF Veteran




Joined: May 2012
Posts: 7,965
Likes: 964
From: Lost in the wilds of Virginia
Year: 1998 Classic (I'll get it running soon....) and 02 Grand
Model: Cherokee (XJ)
Engine: 4.0
CF Veteran
Joined: Aug 2010
Posts: 8,357
Likes: 103
From: Canton, MI
Year: 1999
Model: Cherokee
Engine: 4.0
I use Kroil but I've found that off the shelf Liquid Wrench Penetrating Oil is good. You might try this instead of PB Blaster. Found it at Lowe's and Home Depot.
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CF Veteran




Joined: May 2012
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From: Lost in the wilds of Virginia
Year: 1998 Classic (I'll get it running soon....) and 02 Grand
Model: Cherokee (XJ)
Engine: 4.0
Good to know.
Some years back a machinist's magazine did a controlled study on penetrating oils. They made up a bunch of bolts with nuts and rusted them. IIRC they were fastened on to a piece of plate steel and torqued into place, then a salt water cycle to get them good and rusty.
Then they used various penetrants to see what would work. They measured the force required to turn the nuts. Multiple bolts for each type of penetrant, to average the results.
WD-40 was only slightly better than nothing (no surprise there, it's not a penetrating oil), and PB Blaster was far ahead of most, coming out the 2nd best commercial product. Kroil was the best commercial product, needing only HALF the force of PB Blaster. The acetone/ATF mix needed about half the force of Kroil.
I don't remember if they got Liquid Wrench in the mix, though.
Some years back a machinist's magazine did a controlled study on penetrating oils. They made up a bunch of bolts with nuts and rusted them. IIRC they were fastened on to a piece of plate steel and torqued into place, then a salt water cycle to get them good and rusty.
Then they used various penetrants to see what would work. They measured the force required to turn the nuts. Multiple bolts for each type of penetrant, to average the results.
WD-40 was only slightly better than nothing (no surprise there, it's not a penetrating oil), and PB Blaster was far ahead of most, coming out the 2nd best commercial product. Kroil was the best commercial product, needing only HALF the force of PB Blaster. The acetone/ATF mix needed about half the force of Kroil.
I don't remember if they got Liquid Wrench in the mix, though.
CF Veteran
Joined: Aug 2010
Posts: 8,357
Likes: 103
From: Canton, MI
Year: 1999
Model: Cherokee
Engine: 4.0
Good to know.
Some years back a machinist's magazine did a controlled study on penetrating oils. They made up a bunch of bolts with nuts and rusted them. IIRC they were fastened on to a piece of plate steel and torqued into place, then a salt water cycle to get them good and rusty.
Then they used various penetrants to see what would work. They measured the force required to turn the nuts. Multiple bolts for each type of penetrant, to average the results.
WD-40 was only slightly better than nothing (no surprise there, it's not a penetrating oil), and PB Blaster was far ahead of most, coming out the 2nd best commercial product. Kroil was the best commercial product, needing only HALF the force of PB Blaster. The acetone/ATF mix needed about half the force of Kroil.
I don't remember if they got Liquid Wrench in the mix, though.
Some years back a machinist's magazine did a controlled study on penetrating oils. They made up a bunch of bolts with nuts and rusted them. IIRC they were fastened on to a piece of plate steel and torqued into place, then a salt water cycle to get them good and rusty.
Then they used various penetrants to see what would work. They measured the force required to turn the nuts. Multiple bolts for each type of penetrant, to average the results.
WD-40 was only slightly better than nothing (no surprise there, it's not a penetrating oil), and PB Blaster was far ahead of most, coming out the 2nd best commercial product. Kroil was the best commercial product, needing only HALF the force of PB Blaster. The acetone/ATF mix needed about half the force of Kroil.
I don't remember if they got Liquid Wrench in the mix, though.
Herp Derp Jerp

Joined: Nov 2011
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From: Parham, ON
Year: 1999
Model: Cherokee
Engine: 4.0L OBD-II
CF Veteran
Joined: Aug 2010
Posts: 8,357
Likes: 103
From: Canton, MI
Year: 1999
Model: Cherokee
Engine: 4.0
Thread Starter
CF Veteran




Joined: May 2012
Posts: 7,965
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From: Lost in the wilds of Virginia
Year: 1998 Classic (I'll get it running soon....) and 02 Grand
Model: Cherokee (XJ)
Engine: 4.0
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