Good morning all,

My MS3 is running my 1994 miata well, I just have some issues with idle that I am working through.

I have attached a log, but here are the symptoms;

• Excessively high cold idle (1800 RPM, targets are set lower)
• Sometimes idle will drop, but after a highway drive will go back up around 1800
• Upon first start (cold or hot), car will enter closed loop. After initial start and a short drive, will not enter CL idle again
• I believe the idle valve is working properly

I could possibly have an issue with the idle screw, but I believe I have tested it correctly.

• Using the test mode, lower the valve until the RPM stops dropping (around 32). If I keep going WAY past the point that RPM stops dropping, (say 24) it will start dropping further and stall

Overall, the idle is getting more stable and reliable, but on full warm, it is a bit lower than it should be, around 600 RPM. Other times, it is rock solid at 850.

Appreciate any expertise here!

 

at 32% PWM, what's your idle speed? it should be like 500-600RPM. When cold the idle speed will be higher at the same PWM%.

have you ever played with the idle speed screw for some odd reason?

in your idle settings, you should set 32% as the valve closed value.

 

The idle was around 500- and on second thought it was 27 not 32.

I have set the min/max valve numbers in there also.

I have not touched the idle screw, but the car has had multiple owners and at least one engine swap!

 

That's odd cause I see it's sitting at 27% on those logs when the idle is high

 

Yep. That's what stumps me also. I guess I need to check the screw