Fast idle 79SC
 

Tried several times to do a search, but... anyway

When I start the car, it idles at about 1200-1500 rpm.

After it warms up, it still idles at 1200 to 1500 rpm.

CIS, backfire valve...

Is this an easy fix, or...

Thanks
Tom

Sounds like it may be your AAR, which is the device that controls idle speed during warmup. See a thread by mysterytrain about this. It might also be vacuum leaks, your idle speed setting, or your mixture setting.

In my car, the cold start/warmup idle speed is only slightly higher than the warmed up speed, and it goes down to that speed within about 1 min, so I set it for the idle speed I like it to be at when warmed up and just leave it at that. Even where I live, there is really no disadvantage to not having a much higher speed while warming up. The engine does not stall when cold.

Try setting your idle speed to what you like when warm, and see what happens when cold.

Have you checked your control pressures and mixture setting? How does the car run when warming up and when fully warmed up?

I don't know how to adjust idle speed. Do I need special equipment?

Maybe I need to get a Bentley manual...

On the driver's side of the throttle housing there is a large flat slotted screwhead. Turn it clockwise to lower the engine speed. You may find more info or a pic if you do a search. You canusually turn it by hand.

Let us know what happens once you have done this.

A Bentley is a good idea. So is Wayne's "101 Projects" book.

Thanks P-paul, worked great.
Tom