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will not idle when engine is cold[200/86] posted by mark on
Saturday, 4 August 2001, at 10:45 a.m.
i recently purchased a 1986 240,,the motor has been replaced(only 55,000 miles on it).it will start fine,but i will run for a minute or two,then die.but it runs ok,as long as you hold down the gas pedal,til it gets warmed up..runs perfect when warms up..no vacuum leaks,new oxygen sensor($250)..any help or suggestions is appreciated
Re: will not idle when engine is cold[200/86] posted by John Sargent on
Saturday, 4 August 2001, at 11:41 a.m.
The base idle speed is set with the adjustment knob on the bottom of the throttle body. You should start by cleaning the throttle body and Idle Air Motor. Once you have done that, either pinch off the hose to the Idle Air Motor or ground the red/white wire of the test point (this will close the Idle Air Motor electrically), and set the basic idle speed to 700 to 750n RPM with the adjustment knob. Next adjust the idle mixture with the adjustment screw on the AMM (Air Mass Meter). Connect either an analog volt meter, dwell meter, or Volvo test tool 5280 between the green/white wire of the test point to verify proper idle mixture. The analog meter needle will oscillate when the mixture is correct, or the diode in tool 5280 will turn on and off (equal times on and off). Tool 5280 is simply a diode in series with a 750 ohm resister.
The Idle Air Motors do wear out but your cold idle will probably be fine if the basic idle speed and mixture are set.
Go to the 700/900 FAQ for more information.
--John Sargent