Rough Idle/Check engine light.Possible blown head gasket?
04-06-2016, 08:35 PM
#1
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Year: 1997
Model: Cherokee
Engine: 4.0
Rough Idle/Check engine light.Possible blown head gasket?
My 97 Cherokee 4.0 184,000+ miles had been running rough and the check engine light was on, so i scanned it and here is what it showed.
Stored DTCs
PO303 - Cylinder 3 Misfire
PO304 - Cylinder 4 Misfire
Pending DTCs Detected During Current or Last Completed Driving Cycle
PO300 - Random/Multiple Cylinder Misfire Detected
PO302 - Cylinder 2 Misfire.
I proceeded to do a cylinder compression test and these were my results Cylinder #1 - 150 psi
Cylinder #2 - 150 psi
Cylinder #3 - 70 psi
Cylinder #4 - 70 psi
Cylinder #5 - 150 psi
Cylinder #6 - 150 psi
What other test should I do or what do you guys think is wrong? PLEASE HELP!!!
Stored DTCs
PO303 - Cylinder 3 Misfire
PO304 - Cylinder 4 Misfire
Pending DTCs Detected During Current or Last Completed Driving Cycle
PO300 - Random/Multiple Cylinder Misfire Detected
PO302 - Cylinder 2 Misfire.
I proceeded to do a cylinder compression test and these were my results Cylinder #1 - 150 psi
Cylinder #2 - 150 psi
Cylinder #3 - 70 psi
Cylinder #4 - 70 psi
Cylinder #5 - 150 psi
Cylinder #6 - 150 psi
What other test should I do or what do you guys think is wrong? PLEASE HELP!!!
05-09-2016, 10:18 PM
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Year: 2000
Model: Cherokee
Engine: 4.0
There was a TSB for the valves intermitently not seating right something about spinning them to resolve its worth looking into
can you do a cylinder leak down test ? that will tell you if its holding pressure
can you do a cylinder leak down test ? that will tell you if its holding pressure
05-10-2016, 07:27 AM
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Year: 1998 Classic (I'll get it running soon....) and 02 Grand
Model: Cherokee (XJ)
Engine: 4.0
No it does not. It sounds like a loss of compression on two cylinders.
One of the possible causes is a blown head gasket. There are many others. Don't jump to conclusions without further investigation, unless you enjoy wasting money and time.
OP, do you have any coolant in your oil? Do you have any oil in your coolant? Loss of coolant?
Next step: Do a test for combustion gasses in your coolant. You can buy a kit at any auto parts store.
If the test is positive, you either have a blown headgasket, blown head, or cracked block. At that point, it's time to pull the head to find out which.
If the test is negative, it's time to look at valves.
One of the possible causes is a blown head gasket. There are many others. Don't jump to conclusions without further investigation, unless you enjoy wasting money and time.
OP, do you have any coolant in your oil? Do you have any oil in your coolant? Loss of coolant?
Next step: Do a test for combustion gasses in your coolant. You can buy a kit at any auto parts store.
If the test is positive, you either have a blown headgasket, blown head, or cracked block. At that point, it's time to pull the head to find out which.
If the test is negative, it's time to look at valves.
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