Question anyone running a standalone ECU

[macipusy]

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.

[subytech]

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.

[93forestpearl]

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

[Legacy777]

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

[93forestpearl]

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.

[macipusy]

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

[Legacy777]

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.

[Grayguy]

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.

[93forestpearl]

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

[macipusy]

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.

[Legacy777]

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

[Grayguy]

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.

[macipusy]

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

[93forestpearl]

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

[macipusy]

Tell me more about this stepper motor.

[Legacy777]

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.