Looking for Garrett: High idle

Garrett, what benefits are with a self-adjusted high idle? How did you do it, and why? I would like to know just because my car is idling high due to a little problem. Thanks!

 

I don't think any bad will come of it. In the ECU mine is set to aim for 800rpm but it hardly ever idles at that speed. I also have settings for cold idle that bumps up the idle speed until the coolant reaches 140°F so when I start the car up cold it runs at 1500rpm. I don't notice that too much because I start driving the car and it warms up plenty quick. The actual idle once warm varies between 900-1000rpm depending on intake air temp and if I've messed with the fuel trim knob. I don't mind it running at that speed for idle, I think I've become so used to it that it doesn't bug me. I also didn't hear any complaints from a friend who drove it most of the way back from MI for me last weekend. I think with the low pitch of my car that higher idle sounds normal.

I don't think there are many advantages to running at that speed idle, but I have noticed it gives a little bit better buffer to recover when accessories turn on. It also seems to give it a little bit more stability than the stock idle settings. It may burn a little more fuel during city driving, though I can't say it would be very much.

What is your car doing with its idle? Tell me again what computer you're running. I'm assuming the ICM is still a Subaru OEM unit?

The idle control was the biggest hurdle when we put in the Haltech. Nothing seemed to work short of trying to get a GM stepper motor in there to control idle. Then Todd in his infinite genious figured out how to turn the Subaru 6-wire one into a 4-wire motor.

 

Thanks for the information! At ~600 rpm, the lightened crank pulley looks like it's loose and wobbling. A normal person would quickly guess that the bolt is not tightened enough. I would agree with you that at a higher idle, there's going to be more power produced from alternator to feed the accessories which is good. You probably don't let your car idle too long; more fuel used and a bit warmer coolant. At 600 rpm, that's 10 ignitions every second from the motor, but at 800 rpm, there's 13 ignitions per second. Not a big deal.

Yeah, I have an OEM Subaru idle controller. I will find out soon enough why the car's sick.