idle problems
03-26-2016, 01:07 AM
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Year: 89
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idle problems
hi my jeep Cherokee 89 4.0 inline 6...... is having idle problems after it warms up and i put it in park or neutral it idles at 1500 + rpm but in drive it runs low rpm at 500 to 600 and surges up and down from there. i thought it was my IAC valve and when i changed it my idle whent up to 3000 rpm ?????? i just replaced the tps, map ,cps,spark plugs cap and wires. im not sure why a new IAC would make it run worse. any ideas would help.
03-26-2016, 02:30 AM
#2
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Did you clean TB, especially the cavities around the IAC.
Maybe you accidentally knocked a vacuum line off or loose.
Maybe you accidentally knocked a vacuum line off or loose.
03-26-2016, 11:16 AM
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hi my jeep Cherokee 89 4.0 inline 6...... is having idle problems after it warms up and i put it in park or neutral it idles at 1500 + rpm but in drive it runs low rpm at 500 to 600 and surges up and down from there. i thought it was my IAC valve and when i changed it my idle whent up to 3000 rpm ?????? i just replaced the tps, map ,cps,spark plugs cap and wires. im not sure why a new IAC would make it run worse. any ideas would help.
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03-26-2016, 09:37 PM
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Agreed with all above. Without checking the sensor ground and adjusting the TPS...kind of pointless without that done.
Myself, my socket on the IAC, it's connector waz a b to finally get it clean. Blasting that with contact cleaner ended up solving my intermittent high idle. And like mentioned, knocking a vacuum line off while in there will cause high idle. Also, myself, the O ring and the way it seats in the TB/IAC seemed weird. Short shots of starting fluid will tell you if there is a vacuum leak. Or water works also I hear, I have yet to try that, but it's doubtless less of a fire hazard then any of any of the other options.
It will idle high anytime the intake can get air, via the IAC, manifold gasket, a vacuum line off or leaking.
Myself, my socket on the IAC, it's connector waz a b to finally get it clean. Blasting that with contact cleaner ended up solving my intermittent high idle. And like mentioned, knocking a vacuum line off while in there will cause high idle. Also, myself, the O ring and the way it seats in the TB/IAC seemed weird. Short shots of starting fluid will tell you if there is a vacuum leak. Or water works also I hear, I have yet to try that, but it's doubtless less of a fire hazard then any of any of the other options.
It will idle high anytime the intake can get air, via the IAC, manifold gasket, a vacuum line off or leaking.
03-26-2016, 10:16 PM
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Agreed with all above. Without checking the sensor ground and adjusting the TPS...kind of pointless without that done.
Myself, my socket on the IAC, it's connector waz a b to finally get it clean. Blasting that with contact cleaner ended up solving my intermittent high idle. And like mentioned, knocking a vacuum line off while in there will cause high idle. Also, myself, the O ring and the way it seats in the TB/IAC seemed weird. Short shots of starting fluid will tell you if there is a vacuum leak. Or water works also I hear, I have yet to try that, but it's doubtless less of a fire hazard then any of any of the other options.
It will idle high anytime the intake can get air, via the IAC, manifold gasket, a vacuum line off or leaking.
Myself, my socket on the IAC, it's connector waz a b to finally get it clean. Blasting that with contact cleaner ended up solving my intermittent high idle. And like mentioned, knocking a vacuum line off while in there will cause high idle. Also, myself, the O ring and the way it seats in the TB/IAC seemed weird. Short shots of starting fluid will tell you if there is a vacuum leak. Or water works also I hear, I have yet to try that, but it's doubtless less of a fire hazard then any of any of the other options.
It will idle high anytime the intake can get air, via the IAC, manifold gasket, a vacuum line off or leaking.
03-26-2016, 11:34 PM
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I adjusted the tps and cleaned the throttle body ... how do i check for ground. And what is the proper way to adjust tps ? Thanks
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03-27-2016, 12:38 AM
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When I replaced the iac .... the idle whent up to 3000 so I turned off the jeep and put the old iac back in and it whent back to the same rough idle witch is better than 3000rpm so I dont think i disconnect a vac line. Can these sensor be faulty ?
03-27-2016, 02:04 AM
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Sensor could be faulty, but I would lean towards no o-ring on the new IAC.
03-27-2016, 08:42 AM
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03-30-2016, 11:47 PM
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I just adjusted the tps and got a new se of vac lines all new ..... it's still doing the same stuff when it warms up still at 1500 ram in park and neutral. Still haven't check the ground any tips
03-31-2016, 07:55 AM
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08-08-2016, 05:02 PM
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Ok ill change the fluid first and i dont believe i can bleed it. It was pretty cheap from rock auto compared to the other ones i think they were trying to get rid of them because they werent carrying them anymore.
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