HIGH IDLE HELP
Sorry For Misspelling "vacuum" in the gifs
Here are some helpful threads to look over before you ask any questions:
High Idle Causes are:
1) Sticky throttle cable
2) Sticky throttle component
3) Weak Return Spring
4) Vacuum Leak
5) Fast Idle component
6) Bad Idle Diaphragm / Throttle Controller Adjustment
7) Bad Throttle Stop Screw Adjustment
8) Bad A/C and or idle Boost Diaphragm screw adjustment.
Expansion on # 4)
Two ways a Vacuum leak can increase idle speed:
a) It allows the throttle controller to open the throttle
* Please note in most cases it's not the throttle controllers fault.
The function of the throttle controller is one that uses vacuum
drop to activate.
Though a throttle controller can leak and cause it's own activation,
then throttle controller should be replaced. To test the throttle
controller for leaks directly use a hand vacuum pump and see if
the arm of the throttle controller retracts into the diaphragm and
hold with vacuum applied.
b) It mixes air with a rich fuel mixture and acts as though you have
an open throttle plate. Might include bad float adjustment or
A/F screw adjustment.
Bad Solenoids or Thermovalves can either create a constant
unregulated vacuum leak or block vacuum from reaching it's source
which will leave the connected valve, diaphragm, etc. unable to function.
1) Check for vacuum leaks.
2) Check idle Adjustment.
In each Step (LINK) is a list of other possibilities and/or pre-checks to help ensure that adjustments are made under the right conditions.
Please wait for the animated gif to load, watch and learn.
Vacuum naturally drops as you open the throttle so you don't notice the effects of the throttle controller opening the throttle... however if there is a vacuum leak or a drop in vacuum the throttle controller will open the throttle increasing your engine RPM... it doesn't matter if the leak is intentional or not since most vacuum will all come from the same source, a vacuum leak anywhere effects the entire system.
More in depth animation on the vacuum diaphragm
Originally Posted by Feeding The Fire