coolant bypass the throttle body??

[vincentc]

rjaffey,

Have you done this mod yet? Also, could you please post a simple diagram describing the plumbing of the home depot valve?

Thanks,
Charlie

[rjaffey]

Yes, I've done this mod and it works just fine.

The idle "problems", rather minor in my case; see my posts above, are only present when throttle body (and Fast Idle Thermo Valve) are below 86F or somewhere thereabouts. Above this temp the Fast Idle Thermo Valve is closed and out of the picture. My car's idle is completely normal above this temp. When it's a bit cooler, the idle is a bit high and slightly erratic until the Fast Idle Thermo Valve absorbs enough heat from it's surroundings. Although I haven't verified this, I think it's probably better to leave the Fast Idle Thermo Valve filled with coolant (my mod does this), as heat will transfer into the wax plunger faster than it would through air, thus shortening the period where the idle is faster and erratic.

The problem arises when the Fast Idle Thermo Valve is open, allowing more air flow, while the coolant temperature is aproaching or is at operating temperature. In this case the ECU is trying to reduce the idle speed via the IACV and the dynamic behavior of the engine is not matching what the ecu expects, there's effectively a closed loop operation between measured RPM and IACV duty cycle and having the Fast Idle Thermo Valve open when it shouldn't be as far as the ECU is concerned, throws idle control out of whack.

[This message has been edited by rjaffey (edited June 28, 2001).]

[Holden]

I also have cut and plugged the line from the head to the TB.

I don't notice any idle issues at all now that it's summer.

Greg