Running Lean and overheating
#1
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Year: 1992
Model: Cherokee
Engine: 4.0
Running Lean and overheating
Ok so my 92 Cherokee 4.0 has been overheating since I bought it. I have replaced everything under the hood with no success. I finally gave up and took it to a mechanic who tells me that it is running extremely lean but can't seem to find out why. Do any of you have an idea where to start other than the O2 sensor and fuel filter? Oh yah it runs strong and the CEL is not on.
I could really use some help on this one,
Mark
I could really use some help on this one,
Mark
Last edited by scubamark13; 10-19-2012 at 07:23 AM.
#3
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Year: 1992
Model: Cherokee
Engine: 4.0
Here is what I have done for the cooling system
3 row CSF radiator from radiator barn
Hesco hi flow water pump
Hesco hi flow thermostat housing
OEM 195 tstat
upper and lower hoses
heater control valve
heater hoses
fan clutch
serpentine belt
Radiator cap 13lbs stock and 16lb just to check
new Autometer water temp gauge
B&M trans cooler I also bypassed the radiator
Plugs cap and rotor wires and air filter.
I have also checked the compression all 6 were around 145
had a block test done no gasses in the coolant.
no water in the oil and no oil in the water
electric fan is wired to a switch which is on all the time.
I have checked under hood temps with an IR gun and all temps towards the front of the engine seem ok, its only hot back where the sending unit is and around the back of the motor. I have flushed the motor several times with chemicals and with the Prestone kit.
3 row CSF radiator from radiator barn
Hesco hi flow water pump
Hesco hi flow thermostat housing
OEM 195 tstat
upper and lower hoses
heater control valve
heater hoses
fan clutch
serpentine belt
Radiator cap 13lbs stock and 16lb just to check
new Autometer water temp gauge
B&M trans cooler I also bypassed the radiator
Plugs cap and rotor wires and air filter.
I have also checked the compression all 6 were around 145
had a block test done no gasses in the coolant.
no water in the oil and no oil in the water
electric fan is wired to a switch which is on all the time.
I have checked under hood temps with an IR gun and all temps towards the front of the engine seem ok, its only hot back where the sending unit is and around the back of the motor. I have flushed the motor several times with chemicals and with the Prestone kit.
#5
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Year: 1992
Model: Cherokee
Engine: 4.0
Thanks for the tip but I have burped it several times and there isn't any air in the system.
The mechanics computer is showing that the fuel trim is at -10 on bank 1 which is running lean.
The mechanics computer is showing that the fuel trim is at -10 on bank 1 which is running lean.
#6
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Year: 1999
Model: Cherokee
Engine: 4.0
Actually, a -10% trim is showing that the PCM is trimming fuel off (note the negative (-) sign), which indicates there is a rich mixture that is being compensated for. If the fuel trim was a positive number, like 10%, the PCM is adding fuel to compensate for a lean mixture.
-10% sounds like a long term fuel trim number.
Read this for FYI, and print it off and give it to that mechanic that said it was extremely lean.
http://www.magnaflow.com/07techtips/...in/TB80010.pdf
-10% sounds like a long term fuel trim number.
Read this for FYI, and print it off and give it to that mechanic that said it was extremely lean.
http://www.magnaflow.com/07techtips/...in/TB80010.pdf
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#8
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Year: 1997
Model: Cherokee (XJ)
Engine: 4.0
Here is what I have done for the cooling system
3 row CSF radiator from radiator barn
Hesco hi flow water pump
Hesco hi flow thermostat housing
OEM 195 tstat
upper and lower hoses
heater control valve
heater hoses
fan clutch
serpentine belt
Radiator cap 13lbs stock and 16lb just to check
new Autometer water temp gauge
B&M trans cooler I also bypassed the radiator
Plugs cap and rotor wires and air filter.
I have also checked the compression all 6 were around 145
had a block test done no gasses in the coolant.
no water in the oil and no oil in the water
electric fan is wired to a switch which is on all the time.
I have checked under hood temps with an IR gun and all temps towards the front of the engine seem ok, its only hot back where the sending unit is and around the back of the motor. I have flushed the motor several times with chemicals and with the Prestone kit.
3 row CSF radiator from radiator barn
Hesco hi flow water pump
Hesco hi flow thermostat housing
OEM 195 tstat
upper and lower hoses
heater control valve
heater hoses
fan clutch
serpentine belt
Radiator cap 13lbs stock and 16lb just to check
new Autometer water temp gauge
B&M trans cooler I also bypassed the radiator
Plugs cap and rotor wires and air filter.
I have also checked the compression all 6 were around 145
had a block test done no gasses in the coolant.
no water in the oil and no oil in the water
electric fan is wired to a switch which is on all the time.
I have checked under hood temps with an IR gun and all temps towards the front of the engine seem ok, its only hot back where the sending unit is and around the back of the motor. I have flushed the motor several times with chemicals and with the Prestone kit.
Have you ever figured this out I'm having the same exact issue
#9
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Year: 1998 Classic (I'll get it running soon....) and 02 Grand
Model: Cherokee (XJ)
Engine: 4.0
You are responding to a post that is 7 years old. The OP hasn't been on the forum for over 5 years. I'm pretty sure he isn't going to help you.
Please post your own thread.
Please post your own thread.
The following users liked this post:
Scottishrule38 (09-13-2019)
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