: Odd idling...



JTraik
07-09-04, 08:05 PM
When i start my 68 up it tends to idle too low or too high. When I start it and its a low idle it will choke and die, i have to hit the gas to get a higher RPM idle. When the idle is too high, i dont like letting the car warm up with a high idle and its not very cool to shift into a gear when its at a high rpm...so what i have to to is step on the gas pedal real quick and release then it goes to a normal idle.

Its almost as if something is sticking...its not the linkage, so what could it be? Whats the problem? Thanks!

jk1000
07-11-04, 09:34 AM
What you are mentioning is the operation of the fast idle cam. The fast idle cam holds the throttle open a little more when the engine is cold (choke in operation). It has an adjusting screw, but should not require adjusting unless someone "monkeyed" with it. Sometimes they are set too high. Sometimes the fast idle cam will stick, a good cleaning with carb cleaner will usually do the trick. It is normal to have to tap the gas pedal to bring down the idle.

Just a side note, If your pcv hose is cracked your idle rpm may get too high.

JTraik
07-11-04, 06:31 PM
Well you say it is normal, but may be sticking...ill spray it anyway, where is it located?

jk1000
07-20-04, 01:53 PM
Fast idle cam is on the left side of carb (when standing in front of the car looking under the hood). Be sure all linkages are clean and move without sticking or binding.
Sorry for delay, many things going on.
Good Luck.

Imprl59
07-23-04, 03:55 PM
OK..I'm sure you know this and I'm not trying to insult you, just posting this in case you don't.

You should pump the gas before starting the engine. This sets the choke and the fast idle. If you don't pump the gas the engine will idle slow and be hard to start in cool weather (won't start in cold weather) Once the engine starts and the idle evens out pump the gas again and the choke should set to the appropriate point and the fast idle cam will pull back with it. You said "so what i have to to is step on the gas pedal real quick and release then it goes to a normal idle." This is normal operation for a carb equipped car except for the real quick part. You should be able to just bump it up off idle and when you let go it should fall back to the appropriate idle.

To check the operation of the fast idle cam with the engine off hold the throttle open and move the choke plate open and closed. It should move freely and you should see a linkage moving at the bottom of the carb. There are usually a couple of "steps" on the fast idle cam so that the idle slowly comes down as the engine warms up. Also in many years they used a vacuum dashpot as a choke pull off. When those fail the choke stays closed and the idle is higher than it should be. My guess is that, as other posters have already said, the fast idle cam linkage is sticking and causing your problem.

Steve B.