High idle issues: revisted

[Whizbang]

okay, i still have not found a good solution to my high idle problems and its driving me up a wall.

Here is what the car is doing:

Generally in the morning, ill start the car, it revs high for the 3k warm up, i tap the throttle it goes down to about 2000 rpms. During the course of driving to work, it usually tried to idle between 2000 and 2500 rpms. During lunch time i will choose to idle between normal and 2000 depending on the day. I have watched it idle at about 800 rpms fine. Then just start climbing to 2000 or higher.

What sensors, if not reading properly, can cause such idle issues? I have also noticed the car is running richer (more pops out of the exhaust) and i am thinking they are related.

[Boostmaniac]

Possible vacuum leaks can cause this.

Or you have a massive bridgeport and you just don't want to say that ;)

[Whizbang]

could a bad BAC cause it?

[Boostmaniac]

I guess it could, but it doesn't seem likely. Have you checked for leaks yet?

[Whizbang]

i have but didnt find anything. I am going to look the TID over off the car though

[RETed]

It sounds like the cold start thermowax is sticking, or the TB itself is sticking.


-Ted

[Whizbang]

would that cause the idle to increase while its sitting though? i was under the impression the thermowax doesnt go about 1500 anyway. Hmmm...well i could remove it and see what happens.

[TehMonkay]

I'd probably say its the thermowax as well. I was having the same issue i'm almost sure of it.

[Whizbang]

alright well i will try to remove it this weekend and see what happens.

[Boostmaniac]

I have had a TB stick slightly open, about .5mm and that caused one HELL of a high idle.

Check thermowax, then see if you can actually shut the TB with your hand to drop the idle. If not, let us know.

[RETed]

Try this for a test...
Stick your foot under the gas pedal and lift up.
Does the idle want to drop?
If it does, then it's most likely a sticking TB.
Remove TB and shoot an entire can of brake cleaner or carb cleaner into the bores to clean all the crap out.


-Ted

[RETed]

Wait, I just taught of something really obvious...
Check the throttle cable tension...
DOH.


-Ted

[Whizbang]

Try this for a test...
Stick your foot under the gas pedal and lift up.
Does the idle want to drop?
If it does, then it's most likely a sticking TB.
Remove TB and shoot an entire can of brake cleaner or carb cleaner into the bores to clean all the crap out.


-Ted


this doesn't effect it

[Whizbang]

Wait, I just taught of something really obvious...
Check the throttle cable tension...
DOH.


-Ted

ill see if i can loosen the cable and start it up