Idle Control on V8

[V8 FOU]

Not found it a problem. But it could be wired to cut out the aux valve when the a/c cuts in or even in conjunction with the brake lights. So a/c + brake lights= Main control valve

Cold up to 45deg = Main control valve

Warm + no a/c = aux control valve

Or any other combination you want!

Bit like the old refridgerated Transits that cut out the 'fridge unit on full throttle so the smokey old York engine could actually get up a hill. Only trouble was that you could always tell who thrashed the vans by the number of complaints of melted frozen food!

[redshift]

Sounds good.

When I was researching the problem it seemed that there was no distinct base setting for the throttle bodies. The closed setting was just that and it was left to the IAC valve to sort out the idle airflow. The general result being that if the IAC gets fully closed on most V8s then the engine stalls. Some engines didn't though.

This is why I tried the electronic solution of disconnecting the IAC signal when I didn't want the ECU to hold the revs up, ie gearchanges. Just uses a double pole relay and a microswitch on the clutch actuator.

[V8 FOU]

If you were to have stalling problems, assuming everything else was ok, the answer is to adjust the base idle on the aux IAC valve. Easy to do once you removed the blanking bung.

[Trevsked]

Is that accessable with the plenum in place?

Trevor.

[V8 FOU]

Yes because the aux valve is fitted outside of the plenum. I guess it would be sensible to remove the plug and free up the idle adjust screw before fitting it. I haven't had any problems with it on the stock setting.

[Günter]

Paul, I still can not see how a 'serial' solution covers up problems with really sized IAC valves, sitting in the wrong position .. .

You say that on 'cold engines' the stock valve is the operating one -and your additional is just acting like a fully open pipe ..so this system does not solve problems with a sticky valve plate/valve body in the factory one ..right ?

[V8 FOU]

You are absolutely right. You would need to clean/replace the original valve. All this set up does is prevent the slow decay due to the signal from the ecu. To get an idea of how well this works, disconnect the valve when the car is warm and try it. You will have to reset the mil light as it will throw up a fault code...

[Alex Carter]

proper ends on the gear cables ? pics please and prices

[WEllison]

Using V8 FOU's idle bypass (when warmed up) will also bypass idle increase when extra load is added. (i.e. A/C or power steering).

[V8 FOU]

Using V8 FOU's idle bypass (when warmed up) will also bypass idle increase when extra load is added. (i.e. A/C or power steering).

That's your choice! Either proper idle / better gearchange etc or crap idle but increased for a/c etc.

My car has never stalled over the last 1000 miles of using this system.

Gunter, the aux/second valve is closed when warm, therefore reverting to base setting of around 850rpm.

Prices/pics of this and the gearchange ends etc will follow as soon as I get a bit of time!