No Idle Help!
11-25-2016, 01:38 PM
#1
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Year: 1994
Model: Cherokee
Engine: 4.0 Under Construction
No Idle Help!
1994 XJ 4.0
I have a no idea situation on my XJ, MAP is good, IAC is good but it will not idle. I have good fuel and I can get a rough idle for a few seconds but I have to constantly pump the gas to keep it going for those few seconds. Could this be the TPS bad? The engine hasn't ran in a year I bought it not running as a project. Any ideas?
What I've done
Coil pack
New plugs and wires
CPS
Cam shaft position sensor
Fuel pump
Fuel filter
MAP
IAC
I have a no idea situation on my XJ, MAP is good, IAC is good but it will not idle. I have good fuel and I can get a rough idle for a few seconds but I have to constantly pump the gas to keep it going for those few seconds. Could this be the TPS bad? The engine hasn't ran in a year I bought it not running as a project. Any ideas?
What I've done
Coil pack
New plugs and wires
CPS
Cam shaft position sensor
Fuel pump
Fuel filter
MAP
IAC
11-25-2016, 03:17 PM
#2
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Year: 1996
Model: Cherokee
Engine: 4.0L
what happens when you start the jeep? does it run rough and then die, or runs normal and dies when you stop applying throttle?
in my experience tps won't do that, i had completely removed mine and all it did was not shift out of 1st (again, that's from my experience, maybe there's something else to it but I doubt it)
if it runs rough i would check the downstream o2 sensor
in my experience tps won't do that, i had completely removed mine and all it did was not shift out of 1st (again, that's from my experience, maybe there's something else to it but I doubt it)
if it runs rough i would check the downstream o2 sensor
11-26-2016, 02:14 PM
#3
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Year: 1994
Model: Cherokee
Engine: 4.0 Under Construction
what happens when you start the jeep? does it run rough and then die, or runs normal and dies when you stop applying throttle?
in my experience tps won't do that, i had completely removed mine and all it did was not shift out of 1st (again, that's from my experience, maybe there's something else to it but I doubt it)
if it runs rough i would check the downstream o2 sensor
in my experience tps won't do that, i had completely removed mine and all it did was not shift out of 1st (again, that's from my experience, maybe there's something else to it but I doubt it)
if it runs rough i would check the downstream o2 sensor
It's runs very rough and just for a few seconds for you pump the throttle or hold it down.
11-29-2016, 01:53 PM
#4
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Year: 1994
Model: Cherokee
Engine: 4.0 Under Construction
what happens when you start the jeep? does it run rough and then die, or runs normal and dies when you stop applying throttle?
in my experience tps won't do that, i had completely removed mine and all it did was not shift out of 1st (again, that's from my experience, maybe there's something else to it but I doubt it)
if it runs rough i would check the downstream o2 sensor
in my experience tps won't do that, i had completely removed mine and all it did was not shift out of 1st (again, that's from my experience, maybe there's something else to it but I doubt it)
if it runs rough i would check the downstream o2 sensor
11-29-2016, 03:50 PM
#5
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Year: 1996
Model: Cherokee
Engine: 4.0
Did it get stored for a year because it stopped running, or was it running fine but then wouldn't start after a year of sitting? Verify you have fuel pressure and that the plug wires are hooked up in the right sequence. Maybe an animal made a home in the air box lol 
12-02-2016, 06:26 AM
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I will update once I have done all of this and see what happens.
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12-02-2016, 08:25 AM
#9
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12-02-2016, 09:11 AM
#10
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These types of posts tend to get common this time of year as the temperature drops and the ambient moisture increases. Although many things can cause a fire/bad idle situation, the first and easiest thing you should be checking is your electrical connections. Particularly, your ground connections. It sounds like your system is suffering from low voltage during startup. The computer will fire, but the low voltage will cause the computer to do some strange things, and continuing to run only when the gas pedal is depressed is one of them.
12-02-2016, 01:23 PM
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Year: 1994
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These types of posts tend to get common this time of year as the temperature drops and the ambient moisture increases. Although many things can cause a fire/bad idle situation, the first and easiest thing you should be checking is your electrical connections. Particularly, your ground connections. It sounds like your system is suffering from low voltage during startup. The computer will fire, but the low voltage will cause the computer to do some strange things, and continuing to run only when the gas pedal is depressed is one of them.
https://www.youtube.com/watch?v=AZ1yhT6ywp8
https://www.youtube.com/watch?v=AZ1yhT6ywp8