4.0 replacements and upgrades
Thread Starter
CF Veteran
Joined: Sep 2011
Posts: 10,447
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From: Frederick, MD
Year: 1989
Model: Cherokee
Engine: 4.0
I've search around for this thread but couldn't find it. My xj has 258k miles on it, and its an 89. I wanted to know what parts I should replace or upgrade engine wise. I've replaced simple things like spark plugs&wires and distributer cap. But what else should I replace and what can I add to get a little more juice out of it?
Last edited by my89xj; Apr 18, 2012 at 04:21 PM.
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Joined: Aug 2011
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From: Prescott, Az
Year: 1990
Model: Cherokee (XJ)
Engine: 4.0
60mm throttle body from www.strokedjeep.com.
Have your exhaust pipe re-done without the "crush" and re-routed as necessary.
Get some rebuilt 4 hole injectors from some of the guys on this forum or www.precisionautoinjectors.com.
Have your exhaust pipe re-done without the "crush" and re-routed as necessary.
Get some rebuilt 4 hole injectors from some of the guys on this forum or www.precisionautoinjectors.com.
Thread Starter
CF Veteran
Joined: Sep 2011
Posts: 10,447
Likes: 0
From: Frederick, MD
Year: 1989
Model: Cherokee
Engine: 4.0
Originally Posted by cruiser54
60mm throttle body from www.strokedjeep.com.
Have your exhaust pipe re-done without the "crush" and re-routed as necessary.
Get some rebuilt 4 hole injectors from some of the guys on this forum or www.precisionautoinjectors.com.
Have your exhaust pipe re-done without the "crush" and re-routed as necessary.
Get some rebuilt 4 hole injectors from some of the guys on this forum or www.precisionautoinjectors.com.
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CF Veteran
Joined: Dec 2011
Posts: 3,237
Likes: 1
From: albany, new york
Year: 1988
Model: Cherokee
Engine: i6
[quote=my89xj;1711339]
Why does who sell so many what?[/QUOT
Sorry, why do they sell you so many injectors?
4 holes is too many...: )
Originally Posted by cruiser54
Why does who sell so many what?[/QUOT
Sorry, why do they sell you so many injectors?
CF Veteran
Joined: Dec 2011
Posts: 3,237
Likes: 1
From: albany, new york
Year: 1988
Model: Cherokee
Engine: i6
CF Veteran
Joined: Jan 2009
Posts: 1,964
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From: Baltimore, Maryland
Year: 1994 1993
Model: Cherokee
Engine: 4.0
Yes you'll see more gain from a good set of 4-port "upgrade" injectors. Not only because the 4-port ones deliver the fuel more efficiently but yours are probably pretty stuffed up after 258,000 miles.
Thread Starter
CF Veteran
Joined: Sep 2011
Posts: 10,447
Likes: 0
From: Frederick, MD
Year: 1989
Model: Cherokee
Engine: 4.0
Originally Posted by Programbo
Yes you'll see more gain from a good set of 4-port "upgrade" injectors. Not only because the 4-port ones deliver the fuel more efficiently but yours are probably pretty stuffed up after 258,000 miles.


