legacycentral bbs

Do standalone ECUs work with our stock IAC valves, or do you have to rig something else up?
I want to run the Haltech Sprint 500, which does not have a IAC out, but has aux lines which I can program to run as IAC signals, just wondering if stock IAC's are compatible.

My roomate is runing a Hydra Nemisis, if you talk to Phil at element tuning and have a input output digram of the stock ECU he can pritty much build you anything you want. BTW my roomates car started out as a 92 legacy wagon NA and now has a 2.37 stroker using a 2.2T block 20G heads, manifold and IAC with a perran GT30 rotate mount and STi running gear. He's also using WRC coils with a stock NA harness and the WRX coil harness. Just started it the other day and it runs great so far.

The Hydra and Link can run an IAC valve just fine. I do not know about other systems.

What Dan said. The Link has no problem running the stock IAC valve or utilizing any/all of the stock sensors.

One thing to note: If you switch the voltage and ground pins of the TPS on the old cars, you have a "normal" TPS voltage range.

I'll have to see if the Haltech is just as capable as the Hydra and Link.

93forestpearl wrote:One thing to note: If you switch the voltage and ground pins of the TPS on the old cars, you have a "normal" TPS voltage range.

That's a good idea Dan. Never thought about that.

Dan, do you remember when we started my car the first time, and the link couldn't operate the 3 wire Subie IAC? I wonder why that didnt' work...hopefully it works on the SS. I've thought of converting to a 2 wire IAC, I think audi uses them...idk.

From what I remember Max, we had no control over the IAC valve, which told me it was a wiring issue of some sort.

I know one option for a 2 wire IAC setup is to use a stock boost solenoid from a WRX and fabricate a plate with a hose nipple for the IAC location. THis is my fall back plan if I can't get the stock ej20h IAC to work.

Any of the new Links should be fine with controlling the 3-wire IAC valve.

Well I'm sure I'll be calling you with a few questions when I start wiring the SS for my link Dan, but I have to put together 2 other subies before then.

Too bad I already have the Haltech 500. I guess I'll see how it works out next month when I wire it in.

Not sure what that ECU is capable of. The biggest thing is being able to run a stepper motor for an IAC valve.

Tell me more about this stepper motor.

The newer IAC setups utilize a stepper motor vs. a duty solenoid. IMO they provide finer idle control. I'd love to do away with solenoid base one and go to a stepper motor setup on the TB. It would really clean up the area around the turbo.