motor/trans swap
#1
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Location: Michigan
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Year: 1994
Model: Cherokee
Engine: 4.0
motor/trans swap
I put a 4.0 motor and trans from a 91 XJ in my 94 XJ. It only has 125,000 miles. I'm still using the ecm from 94. I'm running 31x10.5x15 mickey Thompson baja claws. With that being said, why am I only getting 11 mph? Is it my tires or do I need the 91 ecm? Jeep runs excellent.
#3
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Year: 1996
Model: Cherokee
Engine: 4.0 HO Straight Six
But seriously, getting 11 MPGs is not uncommon (I get about that much as well), especially on an XJ that is not 100% stock. So yes, the bigger tires have something to do with it. Do you have a lift as well? That'll effect it. There are 100 things that affect MPGs. Start searching and start tuning up the rig. I highly doubt swapping the ECM would make any difference.
#4
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Year: 1990
Model: Cherokee (XJ)
Engine: 4.0
You have to be sure the speedo is correct. With the larger tires you will register fewer miles driven than you've actually travelled. And yes, your ECU/PCM is just fine and dandy.
#5
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Year: 1994
Model: Cherokee
Engine: 4.0
Yes I have a 3" lift. I figured it was mostly tires, but I went from 17-18 mpg to 11-12 mpg. So I just thought I would ask. You gotta pay to play. Thanks.
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