Tapping only under acceleration.
02-18-2018, 09:32 AM
#16
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Year: 2000
Model: Cherokee (XJ)
Engine: 4.0
02-18-2018, 03:06 PM
#17
Old fart with a wrench
In that case, make sure the "bumpstick" is still good. Check all the lobes with a caliper to make sure none are worn and replace the bearings. In my experience, unless you're building for a specific purpose, use a stock cam if you're going to replace it.
After all the years Chrysler has used the 4.0, they've gotten just about all the horsepower they can out of it and still kept it's longevity and EPA emissions within limits. In other words it's my opinion, don't mess with a good thing!
About the injectors, you can go to 4-holers for better atomization, but remember the PCM controls mixture by varying injector "on-time" so increased flow will be negated by the PCM. A bored throttle body will make a big difference.
After all the years Chrysler has used the 4.0, they've gotten just about all the horsepower they can out of it and still kept it's longevity and EPA emissions within limits. In other words it's my opinion, don't mess with a good thing!
About the injectors, you can go to 4-holers for better atomization, but remember the PCM controls mixture by varying injector "on-time" so increased flow will be negated by the PCM. A bored throttle body will make a big difference.
Last edited by dave1123; 02-18-2018 at 03:10 PM.
02-18-2018, 05:49 PM
#18
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Join Date: Feb 2018
Location: Edgewood nm
Posts: 90
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Year: 2000
Model: Cherokee (XJ)
Engine: 4.0
In that case, make sure the "bumpstick" is still good. Check all the lobes with a caliper to make sure none are worn and replace the bearings. In my experience, unless you're building for a specific purpose, use a stock cam if you're going to replace it.
After all the years Chrysler has used the 4.0, they've gotten just about all the horsepower they can out of it and still kept it's longevity and EPA emissions within limits. In other words it's my opinion, don't mess with a good thing!
About the injectors, you can go to 4-holers for better atomization, but remember the PCM controls mixture by varying injector "on-time" so increased flow will be negated by the PCM. A bored throttle body will make a big difference.
After all the years Chrysler has used the 4.0, they've gotten just about all the horsepower they can out of it and still kept it's longevity and EPA emissions within limits. In other words it's my opinion, don't mess with a good thing!
About the injectors, you can go to 4-holers for better atomization, but remember the PCM controls mixture by varying injector "on-time" so increased flow will be negated by the PCM. A bored throttle body will make a big difference.
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