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91 idles high after bored throttle body

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Old Jan 19, 2010 | 09:16 PM
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white91's Avatar
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From: Wa, St.
Year: 1991
Model: Cherokee
Engine: 4.0
Default 91 idles high after bored throttle body

well i got a used throttle from the junk yard and decided to bore it our at the bottom. Just below the butterfly. I used a flapper drum to take the material off. I also took the sensores off before i started boreing it out. I cleaned it up real good and put the sensors back on and put it on the jeep with a new base gasket. the idle before i started this was at about 900 rpm and now it is stuck on 1100 rpm's. i dont know how to get the idle down. the jeep is a 91 HO automatic. thanks in advance. oh and i did not mess with the surface where the butterfly sits and there is no more light coming through that area than usual.
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Old Jan 19, 2010 | 09:19 PM
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Reset the computer so it can account for more airflow.
Adjust your TPS, since you said you took it out it needs to be readjusted
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Old Jan 19, 2010 | 09:25 PM
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From: New Jersey
Year: 1996
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Engine: 4.0 HO
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x2 on resetting the computer. Just disconnect the battery and hold down the horn for 10 seconds so it drains the capacitor in the CPU and fully drains the power from it. That should do it and be sure to drive it easy for the first little while, otherwise if you drive it hard the computer will raise the shift points and it'll drive like crap.
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Old Jan 19, 2010 | 09:50 PM
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From: Wa, St.
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how do you adjust the tps when there is only t srews in two holes. there isnt anyroom to rotate the tps.
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Old Jan 19, 2010 | 09:58 PM
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Never done it myself, but this should help

Edit: Trying to find right one
Edit 2: I feel like a dumbass, apparently HO does not require TPS adjustment.. Im used to renix.

Last edited by 89Laredo; Jan 19, 2010 at 10:35 PM.
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Old Jan 19, 2010 | 10:26 PM
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From: Wa, St.
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that diagram is not my setup. that looks like a renix setup. my tps is held on with two torq screws on the back side of the throttle body.
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Old Jan 19, 2010 | 10:27 PM
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good point, I forgot you had HO.
Ill look for the right one.. lol
sorry

Edit: see above post, I feel like a dumbass now.

Last edited by 89Laredo; Jan 19, 2010 at 10:36 PM.
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Old Jan 19, 2010 | 10:44 PM
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93XJLI's Avatar
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you positive you didnt go near the slit where the IAC sits?
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Old Jan 19, 2010 | 11:00 PM
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what do you mean by going by the slit where the iac sits. i took the iac out from that adaptor it sits in. all i did was take a 2 1/4" flap wheel on a drill press and fed it into the throttle body down to the butterfly. Should i be looking at the TPS or the IAC. I did disconect the battery to reset the computer. after i did that i started it up and it idled down to 950 rpm's. so I took it out for a short drive and it was back up to 1100rpm. I also forgot to say that when i start it up now it will idle at 1800 - 2000rpm's then come down to 1100rpm's

Last edited by white91; Jan 19, 2010 at 11:05 PM.
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Old Jan 20, 2010 | 11:10 AM
  #10  
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From: Wa, St.
Year: 1991
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does anyone know how to adjust the idle on a 91 HO? is it completely controled by the computer?
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Old Jan 20, 2010 | 11:36 AM
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Year: 1996
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As far as resetting the computer just undoing the battery wont reset it. I would undo it hold the two terminals together for 30 seconds or so to reset it.
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Old Jan 20, 2010 | 07:28 PM
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tried that also. nothing different, still idles at 1000-1100. still can not find how to adjust the idle. i have looked all over.
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