1989 4.0 idling problem
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Year: 1989
Model: Cherokee
Engine: 4.0w/703 injectors
1989 4.0 idling problem
The engine was idling fine to begin with, besides having a miss. I changed plugs, wires, cap, and rotor, then cleaned the throttle body and reinstalled with a new gasket. While cleaning the throttle body I noticed alot of carbon aroung the IAC spindle. I removed the IAC and cleaned it really good. I mean this thing was shining when I finished. When I reinstalled the throttle body and started the Jeep it started running at around 3000 rpms. I shut it of and worked the throttle a few times started it up and it started idling funny. It will idle back and forth between 500-800 rpm's. Today I checked the TPS with a volt meter and it was slightly off. I got it back to specs and restarted the Jeep. It again ran at 3000 rpms. I turned it off and again worked the throttle and restarted it, and it is still running between 500-800 rpms. I looked for a vacuum leak but cannot find one. Any ideas???
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Year: 1990
Model: Cherokee
Engine: 4.0 i6
The renix jeeps don't store codes....... Disconnecting the battery just resets your radio. That's it.
To the OP yes check for vacuum leaks again. Also check the exhaust manifold bolts. On my '90 one of the bolts was loose. I tightenend it up and magically it brought the idle back down.
To the OP yes check for vacuum leaks again. Also check the exhaust manifold bolts. On my '90 one of the bolts was loose. I tightenend it up and magically it brought the idle back down.
Last edited by cherokeelaredo'90; 08-27-2012 at 01:13 AM.
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Year: 1990
Model: Cherokee (XJ)
Engine: 4.0
Make sure your intake manifold bolts are snug.
Which side of the TPS did you use for adjustment? Flat 3 wire connector or square 4 wire?
Ever refreshed all your grounds? Some real critical stuff relies on one ground in particular.
Which side of the TPS did you use for adjustment? Flat 3 wire connector or square 4 wire?
Ever refreshed all your grounds? Some real critical stuff relies on one ground in particular.
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The renix jeeps don't store codes....... Disconnecting the battery just resets your radio. That's it.
To the OP yes check for vacuum leaks again. Also check the exhaust manifold bolts. On my '90 one of the bolts was loose. I tightenend it up and magically it brought the idle back down.
To the OP yes check for vacuum leaks again. Also check the exhaust manifold bolts. On my '90 one of the bolts was loose. I tightenend it up and magically it brought the idle back down.
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Year: 1989
Model: Cherokee
Engine: 4.0w/703 injectors
Well like I said it was running fine before the tune up and throttle body cleaning. So in theory the grounds should be fine. And also in theory the only way I should have developed a vacuum leak is if something became disconnected while I pulled the throttle body. All of that is fine, I have checked the vacuum lines about 4 times now. I am leaning toward thinking it is something associated with the throttle body since it started acting up when I removed/cleand it.
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Year: 1990
Model: Cherokee (XJ)
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Well like I said it was running fine before the tune up and throttle body cleaning. So in theory the grounds should be fine. And also in theory the only way I should have developed a vacuum leak is if something became disconnected while I pulled the throttle body. All of that is fine, I have checked the vacuum lines about 4 times now. I am leaning toward thinking it is something associated with the throttle body since it started acting up when I removed/cleand it.
And FWIW, if anybody owns a Renix and doesn't know for a fact that the ground refreshing has been done, they need to do it themselves.
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Year: 1990
Model: Cherokee
Engine: 4.0 i6
Originally Posted by 67 GMC
Agreed, it doesn't store codes (no one said that), but it does reset the ECU and TCU.
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