Rb20det IACV and AAC guestion

[bigfootap]

Is it possible to run the rb20det without the IACV and AAC and have a decent idle? What would I have to do to make the engine idle right?

[Ramius83]

The AAC valve on the RB motors is meant for idling up the engine when the A/C is turned on and when the power steering pressure switch sees full lock and the pump pulls a load on the engine. The actual base idle is set by the main screw on the valve. Disconnecting the AAC will only disable the A/C and P/S functions of the valve controlled by the ECU. If you aren't running A/C, and don't mind a slight decrease in RPMs when in full lock/turn, then leave it disconnected.

[bigfootap]

What does it mean if I unplug my IACV(the one with the screw on the side of it on the back of the manifold) and the car dies?

[Ramius83]

Well, the first question is, what is your car doing now with it plugged in before you unplug it? What is your TPS set at? Base timing set correctly? Etc, etc etc.....

[bigfootap]

the problem that I'm having is that it won't idle. NO matter what i set correctly it won't idle right. No vacuum leaks, no boost leaks. The base timing is set correctly. I cannot seem to get a correct reading from the tps no matter where I put the leads, does anyone have a picture of where to put my DMM leads? If i move the tps alittle bit it will idle around 1500 or even higher when I'm driving it and come to a stop. and if i move it the other way it will just die.

[Ramius83]

Well, since you have been messing with the TPS with no known voltage value readings, you need to set that FIRST. The TPS sensor consists of a ground wire, a 5 volt feed to the sensor, and output from the sensor to the ECU. The center wire, what-ever color that may be, is the voltage going back to the ECU. This is the wire that you will back-probe when setting the TPS sensor. Use a T-pin of some sort and insert it into the back of the center wire terminal at the connector of the TPS sensor. Then, attach your DMM Red lead to that T-pin. Then, attach your DMM Black leak to battery/engine ground. Then start your engine and let it idle if you can. Adjust the TPS until it reads about 0.50 Volts +/- 0.05 Volts, ideal is 0.50 Volts. After that, set your base idle. Adjust the screw all the way out and it should be idling high. Then ring the screw in until you reach your desired idle RPM.

BTW, all it takes is VERY SLIGHT movement of the TPS sensor to get big voltage difference readings.

[bigfootap]

which plug on the TPS am I suppose to probe?

[Ramius83]

Should be the bottom plug. But, I think it does not matter.......Page EC-65 of the R34 Engine Manual that you can download from Phase2motortrend........

[bigfootap]

I also noticed when driving the car and then coming to a stop that it will idle as long as I don't push in the brake pedal, it won't idle steady or anything but it will stay on. It will cut off if I hold the brake pedal in.