High idle 3.0 SC

[jmancool]

Hi Everyone, have you ever heard the phraze "if you want it done properly, do it yourself"...... well here goes.

I've had this 1979 SC now for a few months and have been sorting out many issues out that have been caused by a previous mechanic. Most annoying has been the high idle but only when the engine was cold. After checking everything - vacuum leaks, IAC, etc. I was running out of ideas. Once I had pulled off all the idle control pipes and put them back on, the car started and idled normally - about 1200 -1300 rpm cold but now it wouldn't idle when the engine was hot.

Well ...... this is what I found, the nitwit mechanic that had the car a part before had moved the Throttle Lift Valve over and caused the throttle link to hit the bracket and hold the throttle plate open too far - hence the high idle when cold. When the engine heated up and the IAC closed the idle adjusting screw was screwed right in and therefore the idle when hot was OK. The mechanic had even backed off the bass idle adjusting screw on the throttle plate trying to get the idle down - hence why it was stalling now when the engine was hot.

Now the throttle plate is adjusted correct, the idle screw is set correctly and the engine now idling fine - hot and cold.

Another saga fixed.

Cheers JP

[T77911S]

not sure of some of your terms, IAC?, throttle lift valve, ( the thing in your pic is the decel valve). base idle adjusting screw on the throttle plate? are you refering to the big screw in your pic, which is used to adjust the idle, or the little screw that adjusts the resting position of the throttle plate, which should not be messed with?

anyway, its always good to get things fixed where it does not cost anything, good job.