BP: what's that valve for?

[Pocket_Rocket]

Hi guys, I was stripping down my old BP engine for salvageable parts when I saw a valve bolted under the intake manifold. It's got two water lines going to it, and when taken appart, I figured it was some kind of air bypass valve. What is it for? Isn't there already a bypass valve (IAC) on the throttle body to control the idle? Could this part be the culprit for my surging idle/ stalling problems, (which happen only when the engine is warm, after long drives), even though I've set and cleaned my TPS and throttle body to specs?

[aspireguy95]

i think what ur explaining is the vics

[Pocket_Rocket]

Nope not the VICS; the VICS actuator is on the passenger side of the intake. Well, as you may know, the BP intake is made from a bottom and top part, right? The valve I'm talking about is bolted to the bottom of the TOP part, so you can't really see it unless you take the manifold appart. And there are some coolant lines going to it.

[Pocket_Rocket]

Here you go:

[Nerd Racing]

its the cold idle thermowax valve. It would cause sparatic idle. Hey man, where did the coolant line from by the TPS go to? care to shoot me a pic? I can't figure it out on my BP, it wasn't complete when I bought it.

[jglutz]

Idel Air Control...IAC

[Pocket_Rocket]

its the cold idle thermowax valve. It would cause sparatic idle. Hey man, where did the coolant line from by the TPS go to? care to shoot me a pic? I can't figure it out on my BP, it wasn't complete when I bought it.

I didn't get my digital camera from repair yet, bet I guess I could take a look to see where the lines hook up...

[Nerd Racing]

you would be my hero if you could take a look. its the one that faces the firewall when the engine is installed.

Thanks a ton man!

[j-stauf7]

IAC can be located in that spot instead of on throttle body.

[Pocket_Rocket]

Nerd_Racing, I took a look, and the line going from the back of the throttle body goes to the nipple facing the rear of the car on the valve. The line that goes from the downward facing nipple goes to the other nipple on the metal coolant line near the t-stat.

[Nerd Racing]

thanks man I found it, it was wedged so far up into the intake runners that I thought it was connected to something.

awesome man! did you figure out your idle issue?

[Pocket_Rocket]

No, not yet; I've got a couple of small issues to get rid of to isolate the idle problem, like oil leaking in the distributor's electronics, and a hissing, RPM-dependent sound comming somewhere from the intake manifold, which may be a vacuum leak, but can't pinpoint where. The thing that I think is weird is that the problem suddenly appeared after a 45 minute highway drive last autumn, when I got off the highway and got to a stop sign...