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Can't adjust base idle 765Turbo[740-760/86] posted by nick c. on
Wednesday, 17 June 1998, at 10:32 p.m.
I can't seem to adjust the base ible on the '86 760T wagon. I know that in adjusting the base idle I have to ground a terminal located near the passenger shock tower. No matter how much I turn the idle adjustment knob out the idle still is a bit lower that the specified rpm. I definately know I do not have any vaccum leaks. I checked the throttle body and cleaned it but still to no avail. Any ideas?
Re: Can't adjust base idle 765Turbo[740-760/86] posted by johnb on
Thursday, 18 June 1998, at 9:08 a.m.
When you clean the tb you also have to remove the big black screw and blow out all the passages. this screw adjusts the tb bypass air...when the right wire is grounded the aic shuttle is centered and you adjust tb bypass air with the big black screw. When the wire is connected the ecu can then control idle.
If idle won't adjust two possibilities come to mind:
1. the aic motor/valve is stuck or you're grounding the wrong wire.
2. passages from back of tb plate to front of tb plate controlled by big black screw are clogged.
Re: Can't adjust base idle 765Turbo[740-760/86] posted by Steve Seekins on
Thursday, 18 June 1998, at 12:48 p.m.
If everything is clean and clear, you may have to adjust the throttle stop screw slightly. After cleaning a throttle body, hold it up to a bright light and look to see if there is a nice even rim of light around the throttle plate. Also, when you clean, be sure to clean the EDGE of the plate AND the area of the bore where the edge of the plate is when closed. If you do not get that even rim of light, then the TB is not cleaned properly, the plate is not installed correctly on the shaft, or the throttle stop screw is not properly adjusted. HOWEVER, this is not something that normally needs to be done on an engine that was running fine. I would look to other problems - measure the manifold vacuum, check the timing (ignition AND valve), etc. Slipped timing belt may not allow engine to idle where it should.
Steve Seekins,