Findings on programming ECU
#1
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Year: 1998
Model: Cherokee
Engine: 4.0L
Findings on programming ECU
I went to the dealership to see if I could have them reprogram my 98 XJ ECU to reflect bigger tires (32s) and re-geared axles (4.10).
Funny enough, the service advisor was a nice guy who drives a highly modified JK and was totally into it.
According to him, Chrysler can only program parameters that were an originally offerred option on the vehicle. So for axles, the largest offered ratio ever was 3.73, which means it's the top value they can write to the ECU. Same goes with wheels and tire sizes, etc.
Which leaves XJ owners with some very limited choices, such as Superchips, etc. I do have a Superchip for my Chevy and it works great. I modified my tire size, the shift points, fuel grade, rev limiter, etc.
Can all these be modified for an XJ as well? Does anybody know which Superchip model works for XJs. The one listyed for the JK/Dodge, did not have XJ listed in there...
Thanks.
Funny enough, the service advisor was a nice guy who drives a highly modified JK and was totally into it.
According to him, Chrysler can only program parameters that were an originally offerred option on the vehicle. So for axles, the largest offered ratio ever was 3.73, which means it's the top value they can write to the ECU. Same goes with wheels and tire sizes, etc.
Which leaves XJ owners with some very limited choices, such as Superchips, etc. I do have a Superchip for my Chevy and it works great. I modified my tire size, the shift points, fuel grade, rev limiter, etc.
Can all these be modified for an XJ as well? Does anybody know which Superchip model works for XJs. The one listyed for the JK/Dodge, did not have XJ listed in there...
Thanks.
#2
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Year: 2000
Model: Cherokee
Engine: 4.0
There are charts online where you find your gearing and tire size, then you just buy the correct tooth speedo gear. They are about $30.
#3
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Year: 1992
Model: Cherokee
Engine: 4.0 high output
There is a speedo gear in your tcase that can be replaced with a different tooth count to correct the speedo
Last edited by xjheep92; 08-01-2012 at 10:25 AM.
#4
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Year: 1998
Model: Cherokee
Engine: 4.0L
My Chevy, once adjusted with the Superchip, drive much better and burns less fuel...
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Year: 1991
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Engine: 2001 4.0L
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