I am wondering if its possible to make this whole setup work. I am in the middle of fabricating a custom intake manifold and am curious of the challenge it will arise if I bypass the IAC completely along with the Fast Idle Thermo Valve. I am running with an OBD-I ECU. I understand I will obviously not get the car running high rpms on startup.

Basically both ports that feed to the throttle body via the intake manifold must be bypassed in this design. Has anyone ever done this before? If this wouldn't work, how could I appoach the situation to make it work. Could I modify the Throttle Body etc? TIA

 

It will work. Just bypass the IACV and run the coolant line directly from the block to the line coming out of the TB.

 

If you dont' have an IACV, you will have a high, roaming idle, and you'll throw a code from the IACV sensor. I believe that you'd be fine without the FITV as long as the IACV was there. It will still run, but it's annoying as hell at stop lights - especially if you have a loud exhaust!

 

Thanks guys! I'm sure there's gotta be a way to hook everything up so there is no roaming idle. I'd like a car that acts like a car on standalone or carburated. Turn it on, watch it idle at like 800rpm at cold....

How does the ECU make the idle roam if it can't control the amount of air the engine is getting and only fuel?