Jeep Cherokee running rough low idle at 200-300 rpms
10-05-2015, 09:40 PM
#16
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Model: Cherokee
Oh so the first tac is 500? Alrighty then that's where it's currently idling. Gunna pull the IAC again and inspect it. Might be smart to just replace it
10-05-2015, 09:55 PM
#17
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Year: 1991
Model: Cherokee
Engine: 1999 4.0L
Fuel pressure is mechanical. Either the fuel pump is bad or the pressure regulator is bad. You can isolate by pinching off the return line from the regulator--if pressure goes up to 40 or higher then the regulator is defective, but if pressure stays low then its a problem with the pump. Not sure if the RENIX era had the ballast resistor, could be defective too.
10-05-2015, 10:15 PM
#18
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Year: 1990
Model: Cherokee (XJ)
Engine: 4.0
Fuel pressure is a real issue here. Did you not read my post above?
10-05-2015, 10:16 PM
#19
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Year: 1990
Model: Cherokee (XJ)
Engine: 4.0
Fuel pressure is mechanical. Either the fuel pump is bad or the pressure regulator is bad. You can isolate by pinching off the return line from the regulator--if pressure goes up to 40 or higher then the regulator is defective, but if pressure stays low then its a problem with the pump. Not sure if the RENIX era had the ballast resistor, could be defective too.
10-05-2015, 10:28 PM
#20
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Just now getting it cruiser, phone refreshing slowly. Done with MAP as that isn't the culprit after fixing that line. Pulled the IAC to double check it. Should I be able to gentle push and pull the plunger in and out on it? Also where is the return line on the regulator so I can check that as well while I have the fuel pressure gauge rented
10-05-2015, 10:32 PM
#21
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Year: 1990
Model: Cherokee (XJ)
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Front of the fuel rail off the fuel pressure regulator.
10-05-2015, 11:07 PM
#23
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Year: 1990
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Yes. But only for a few seconds.
10-06-2015, 09:30 AM
#24
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Year: 1999
Model: Cherokee
Engine: 4.0
Nooooooooooooooooooooooooooooooooooooooooooooooooo oooooooooooooooooooooooooooooooooooooooooooooooooo oooooooooooooooooooooooooooooooooooooooooooooooooo oooooooooooooooooooooooooooooooooooooooooooooooooo oooooooooooooooooo!!!
Fuel pressure is a real issue here. Did you not read my post above?
Fuel pressure is a real issue here. Did you not read my post above?
10-06-2015, 09:34 AM
#25
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Year: 1990
Model: Cherokee (XJ)
Engine: 4.0
Just now getting it cruiser, phone refreshing slowly. Done with MAP as that isn't the culprit after fixing that line. Pulled the IAC to double check it. Should I be able to gentle push and pull the plunger in and out on it? Also where is the return line on the regulator so I can check that as well while I have the fuel pressure gauge rented
I use a PC.
So this app has a mind of it's own and works on it's own timeframe?
10-06-2015, 09:48 AM
#26
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Year: 1999
Model: Cherokee
Engine: 4.0
Just now getting it cruiser, phone refreshing slowly. Done with MAP as that isn't the culprit after fixing that line. Pulled the IAC to double check it. Should I be able to gentle push and pull the plunger in and out on it? Also where is the return line on the regulator so I can check that as well while I have the fuel pressure gauge rented
No.
The IAC pintle is pretty much solid if it is properly connected to the motor gearing inside of the IAC.
10-07-2015, 11:01 PM
#28
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Year: 1990
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10-07-2015, 11:44 PM
#29
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Replaced entire fuel assembly and IAC. Was running slightly better but still low rpms. Now it starts up and immediately dies.. One step forward and two steps back
10-07-2015, 11:53 PM
#30
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Egr resistor somehow got the ground unplugged. Still idling poorly though, could it be a plugged cat? Exhaust work by PO left exaust system rattling pretty bad