22 replies to this topic

[Randy Thieme]

Randy did you ever find the answer to this question.?

ever since I advanced my timing and adjusted my fuel pressure I notice my idle is about 1400. I tried to back out the idol adjuster with the nut on it but its all the way out. could not find or hear a Vacuum leak. the cable is free. It seams to be correlated to when I advanced the timing. Any further thoughts.

No I did not fix it. If I ever do will post the answer. I tried swapping an IAC from Craig's List to no affect but may try that again. I know at least one other driver who claims to have a car with fast idle and gave up fixing it. This person owns a repair shop so they've got ample resources. Does not bode well for me.

The question is timed just right as I did get some more info last weekend - and this is weird. At some point I don't know how or when my cooling fan got unplugged. Coming out of impound I was waiting for a few other cars to clear to get to my paddock space. All of a sudden the 220F idiot light I installed is glowing. Security worker is still holding me while a car or two goes by. Get back to paddock and it must have gotten to 230F. No leaks or bad engine behavior afterwards. But - now it will slow down to 1200 RPM when idling. Go figure!

I know there are two mechanical adjustments. One is the screw that is accessible from the top of the throttle body. I believe that adjusts bleed by. The other is a butterfly stop screw located at the bottom of the throttle body. The second one sounds like the one you were playing with. If so might try the top screw. I don't know about fuel pressure but advancing the timing can speed up the idle, but I don't think it would speed it up that much. Have you tried the obvious of un-advancing the timing to see if that fixes it?

[Kyle Freiheit]

Randy did you ever find the answer to this question.?

ever since I advanced my timing and adjusted my fuel pressure I notice my idle is about 1400. I tried to back out the idol adjuster with the nut on it but its all the way out. could not find or hear a Vacuum leak. the cable is free. It seams to be correlated to when I advanced the timing. Any further thoughts.

I found that my ISC valve seal wasn't sealing. I just put a piece of tape across it to make a dead end gasket and it dropped my idle significantly when I was looking for leaks.

http://www.miata.net/garage/isc.html


Kyle

[FTodaro]

I found that my ISC valve seal wasn't sealing. I just put a piece of tape across it to make a dead end gasket and it dropped my idle significantly when I was looking for leaks.

http://www.miata.net/garage/isc.html


Kyle

This is very helpful I wonder if it is the same for a 1999. I have not changed the timing back. I would live with it for awhile as I had to set the timing on the dyno and I do not want to do that again right now. I will read the above and see if I can make sense of it.