1990 Volvo 240. I want to adjust the base idle and the off idle point of the idle control switch that is mounted to the throttle body. I looked in the archives and my Haynes manual and the procedure they state is to ground the blue and white wire of the blue two pin test connector by the coil and also to turn the black **** by the throttle body to adjust the idle. Two problems though.....my car does not have the test connector of the black ****. It looks like the only ways to adjust the idle are to either use the locking set screw on the underside of the throttle lever, turn the plastic adjustment fitting on the throttle control cable, or fiddle around with the linkage setting between the throttle cable pivot the the throttle lever.

I really don't want to mess this up so can anyone point me in the right direction for this type of setup?

Many thanks,

 

Have done this a thousand times - And yes earlier cars without an idle motor have a black screw adjuster, and some cars have a wire to ground out to take the idle motor out of the equation.

Clean throttle plate
Loosen throttle switch (so it can be moved with a little force, not floppy)
Start car, warm up engine
Block off one of the aux air hoses going to the iac/idle motor/air valve/what you want to call it. (I used to simply clamp one off, but those hoses are probably pretty brittle by now! so you'll have to figure out either to clamp or block off 2 fittings, the hose and where it plugs in on the manifold or throttle/air filter hose)
OK - with idle motor out of the mix (blocked off) adjust the idle speed to 750 rpms with the setscrew and locknut - the throttle switch may prevent the plate from closing (from a previous adjustment with a dirty plate) so adjust throttle switch accordingly. (sometimes I would simply tap the throttle switch with the end of a screwdriver to nudge it and allow the throttle to close as needed)
Turn engine off and set the throttle switch to "click" when you slightly open the throttle plate. You can hear the microswitch click if you listen carefully. Sure you could use your ohmmeter and ----------------------------------------- listening is faster/easier.
Start car and unclamp the idle motor hose - the car should idle at 750 and if the idle motor works - when there is a load on the engine (ac/alternater/Powersteering) the idle speed should stay the same and when the engine is cold the idle speed should be slightly higher..

 

Thanks Hoonk, I will give it a go this weekend when I actually have a little time to spend on it. Just to be clear, I need to block off all the hoses/fittings that go to the idle motor, or just a specific one? Thanks for the help. The car runs well, just has a high idle right now (about 950 RPM give or take a few)

 

Simply prevent air from flowing thru the idle motor, however you want to do it. Easiest is to clamp one hose shut, but that might crack and damage the hose if it's not soft rubber any longer.

 

Got it! Thank you!!