I have a 1993 Turbo Miata running a megasquirt 2 plug n play. It currently idles at 2700 rpm! I have tried everything. I got a new throttle body. The idle adjustment screw is screwed in all the way down. I tried playing with all the megasquirt idle controls with no success. I made sure the throttle cable was good. The throttle body has a new gasket. Does anyone have any idea why it could be idling so high. Any suggestions will be greatly appreciated. Is it my megasquirt settings? Anything mechanical? Thank you!!

 

Post a datalog and tune file (msl and msq)

 

Big vacuum leak,,check the rubber plug on the back corner of the intake manifold . Fredb

 

Here are the datalog and tune

 

Check for vacuum leak, also your idle fuel cells may be uneven, does it hunt up and down for idle.

Don't go by what I say though, still learning, my idle issues were pretty much tuning issues and a vacuum leak, which I found by spraying some brake clean around the intake when it was running, it will bog down the motor a quick sec when you find it. . . also even out your idle area in your fuel table, that will help as well.

 

does anyone know what I need to do? I'm trying to sell the car so I need to get this done ASAP. Thanks!!

 

I'll buy it for 2 nickles.

 

I'm not where I can open the msq so tell me where your IAC valve minimum DC is set?

 

tune.

 

Does the RPM change at all when the idle DC% changes?

 

Here is a screenshot of the IAC valve DC. there is a setting under Idle control called valve mode. There is normal and inverted I was on inverted so would changing it to normal do anything??. Thanks

 

Unplug your IAC.
Unplugging it will close the valve.

If idle drops, you have a setting problem.
If it remains high, at 2700 RPM like you said, you have a big vacuum leak.

Check to see if you still have the restrictor orifice in your PCV line.
Check your brake booster / booster line.