Loss of Power
#1
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Model: Cherokee
Loss of Power
Hey all so ive had this problem for a few months.
I have a 1992 Cherokee xj 4.0 4x4 Auto
I have no power after 3000 rpm. When I accelerate past 3k rpm i stop speeding up. If i floor it it will Jump to 4k rpm but not go past 4k, I also lose all moving power depending on speed the jeep will either start slowing down or maintain the same speed. If I gas it in neutral it will go all the way to rev limiter no issues. So it appears to only do this while under load. Also running a/c or going up a grade the issue will happen at lower rpms ex 2600-3000 rpm
I have checked back pressure 0-1 psi, Fuel Pressure 31 psi and with regulator disconnected 47 psi.
Any help would be much appreciated.
I have a 1992 Cherokee xj 4.0 4x4 Auto
I have no power after 3000 rpm. When I accelerate past 3k rpm i stop speeding up. If i floor it it will Jump to 4k rpm but not go past 4k, I also lose all moving power depending on speed the jeep will either start slowing down or maintain the same speed. If I gas it in neutral it will go all the way to rev limiter no issues. So it appears to only do this while under load. Also running a/c or going up a grade the issue will happen at lower rpms ex 2600-3000 rpm
I have checked back pressure 0-1 psi, Fuel Pressure 31 psi and with regulator disconnected 47 psi.
Any help would be much appreciated.
#4
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Year: 1998
Model: Cherokee
Engine: 4.0L H/O
A common problem seems to be the catalytic converter restricting the motor. Under load the motor makes more exhaust gasses then just in neutral.
#5
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That's what I originally thought might be happening. So, I did an exhaust back pressure test and it read 0-1 psi from idle to rev limit. The test was conducted when the engine was cool and during normal operating temp.
#6
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Year: 1998
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Engine: 4.0L H/O
#7
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Trending Topics
#8
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Year: 89
Model: Cherokee
Engine: 4.0
Vacuum test & pay attention to the scenarios listed here....
http://www.secondchancegarage.com/public/186.cfm
http://www.secondchancegarage.com/public/186.cfm
#9
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Year: 1998
Model: Cherokee
Engine: 4.0L H/O
Vacuum test & pay attention to the scenarios listed here....
http://www.secondchancegarage.com/public/186.cfm
http://www.secondchancegarage.com/public/186.cfm
#10
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Vacuum test & pay attention to the scenarios listed here....
http://www.secondchancegarage.com/public/186.cfm
http://www.secondchancegarage.com/public/186.cfm
Also, today it started doing it at 1.8k - 2k rpm.
#11
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Update, so something very peculiar just happened. I started doing a fuel volume test, and my fuel rail has A LOT of air bubbles in it (like half air half fuel)..
#12
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Solved!!!!!!!!
After seeing all the air in the fuel rail. I pulled the fuel pump and the fuel pump strainer was not there. From my understanding the strainer is important for keeping the fuel pump primed. So I decided being that the pump probably sucked up whatever crap was in the bottom of my gas tank I would just replace the whole unit now while i have the money.
I did buy a vacuum gauge tester. I won't be needing it now but it will be nice to have in the future.
A big thankyou to everyone for their advice and help.
After seeing all the air in the fuel rail. I pulled the fuel pump and the fuel pump strainer was not there. From my understanding the strainer is important for keeping the fuel pump primed. So I decided being that the pump probably sucked up whatever crap was in the bottom of my gas tank I would just replace the whole unit now while i have the money.
I did buy a vacuum gauge tester. I won't be needing it now but it will be nice to have in the future.
A big thankyou to everyone for their advice and help.
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