High idle

[rnoswal]

There should be an air screw on the front side of the intake manifold just right over the butterfly. Try screwing it in some and see if that helps. You might have knocked off a vacuum hose, but that amount of timing sounds like just a turn or so on that air screw should do it for you.


Russ

[suprra_girl]

did you do the ign timing with the diagnostic pins connected?

yea i would try vacuum leaks.... do you have an aftermarket boost gauge?

get some carby cleaner and spray around the intake and vacuum areas and see if your idle changes

if it does... you've found your leak

[nickvash0104]

Actually, I've got an NA No turbo here...

I'm fairly certain I have a leak somewhere along my intake as it's starting to crack around the lip of the angle tube - I'm still looking for a replacement aftermarket solution, but for NAs, there seems to be very little that has just the tube.

[suprra_girl]

ahhh k i'll reword it... if you had an aftermarket vacuum gauge you could see what your vacuum is at idle and you'd know straight away if you had a leak

if you have any cracks in piping between the afm and throttle body or intake manifold leaks or vacuum leaks this will screw with your idle

[rnoswal]

A possiblity until you find another tube is to put some silicone on the cracks. That will seal them up, plus remember the vacuum hose under the tbe that connects to the power steering pump. It is just a bit easier not being turbo charged in finding a leak, but there are a lot of vacuum hoses to check, so the spray is the easiest way to check it out. Even an open EGR valve will mess with the idle.


Russ

[nickvash0104]

I'm going to go w/ a compression test - too much work to play guessing games on my daily driver

I'm assuming a BHG will also distort idle... grabbed a test kit today, just waiting for the car to cool off so I can test it.

[rnoswal]

A blown head gasket will distort the idle in that it will cause a missfire as water or oil gets on the plug and fouls it out. An air leak of somesort is what will cause the higher idle speed. If you have an air leak in the tube anywhere before the butterfly valve then the idle will be lower because of not allowing the airflow meter vane to open like it should. Anywhere on or after the butterfly valve will cause the higher idle. I could be the cable that is not allowing the throttle to close all the way, or a gasket blown out somewhere along the intake.


It could even be your distributor. It may have come loose and is advanced too far. There are enough vacuum hoses to cause the higher idle and like the girl said, spray WD 40 around the intake and hoses, lightly, and see if the idle changes any. You could also get a stethescope and listen carefully and see if you can hear a place where air might be getting in unwanted. If you find a BHG, then never mind, as that has to be fixed first.

Even the idle speed control valve could go bad.

Russ

[nickvash0104]

I'd adjusted the screw - you're talking about the one near the throttle body, right? I adjusted it to the lowest RPM position and it's still idling too high (I knew it was the lowest RPM position because the other direction revved the engine higher)

[WiseAssJester]

The cams still stock? On a larger motor a massive cam will bump the idle up. My 350 has to idle at about 11-1200 after warming up to keep the lope from the cam from killing it.

[nickvash0104]

Yep, still stock - only thing that isn't stock in regards to engine parts is the air filter.