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Fast idle on start up[240-260/1983] posted by Dennis on
Monday, 27 April 1998, at 3:07 p.m.
Bricksters,
My 240 turbo B21ft, idles about 2000 rpm when started, after about 5 minutes it will return to set idle speed of around 900 rpm.
I set the idle per Bentleys, I replaced all sensors on the intake side of engine, new gasket, idle control valve, replaced all vaccum hoses, has year old wiring harness, intake was bead blasted, co2 within specs. It did not do this befor I did all this work.
Im at a loss, what have I missed, any help is appreciated! Thanks in advance!
1983 240 turbo upgraded inter & water cooled.
Re: Fast idle on start up[240-260/1983] posted by abe crombie on
Monday, 27 April 1998, at 11:39 p.m.
the sensor that is located nearest #1 intake runner porvides a varying resistance that goes up in ohms as temp gets colder. If it has a faulty connection the idle control unit will assume the high (infinite) resistance is a sign of really cold temp and it will run idle valve at maximum control opening and you will get 200rpm idle speed until connection improves at which time idle goes back to normal. Clean and tighten (push sides of connectors in connector housing closer together for tighter contact with male pins on sensor) and see if your trouble ends.