I have a 1990 rx7 convertible.
My mom bought new and has handed it down to me 34 years later.
I have noticed the following :
In the past when cold starting the car it has always revved high for a for 10-15 seconds before the idle drops to normal .
Lately when I start it , it hasnt been doing this . It runs fine but this is out of the norm for a car that has done this all its life. Any thoughts on this or suggestions to fix if this happens to not be a good thing????????

Thanks David

 

I believe the high idle upon cold start is triggered by 1 or 2 solenoids, the accelerated warm up solenoid (aws) is one, I forget the name of the 2nd. They are mounted on the upper intake manifold on usdm turbo cars, I’m not sure where they’re mounted on non turbo cars.

So that being said, you could probably test the solenoids, and test for the ecu triggering the solenoids and their grounds. Could also be a false resistance value coming from the coolant temperature sensor for the ecu, but you’d probably have drivability issues at cold start temps too.

I believe people argued the high idle was not ideal upon cold start as it creates more wear than a lower idle, and it’s true purpose is to warm up the catalytic converters. So I’d argue as long as the car can idle when cold without the high idle, it should be fine, but I’ll let others chime in.