IAC valve, does it need coolant?
 

I used to have a supercharger in my car so the IAC valve was gone. I installed a IAC valve but didnt hook up the coolant hoses through it. The valve worked for 5 minutes and now is shut at 8% dc and wont move. Did I kill it? Does it need to have the coolant hooked up to it? I thought the coolant through the TB was just to prevent condensation, I dont drive this car during winter anyways.

Well, now it works again. The IAC valve works properly and then after I tap the gas while at idle the rpms hang at 1300rpms, they wont go back down to 850-900. It must be a megasquirt setting.

The coolant line is there to prevent icing. It's heating the throttle body, not cooling it.

Do you think maybe its sticking open?

I think you need to learn to tune. Do you know what the idle valve test menu is? It would tell you if it's sticking or not...

You are right, I need to learn how to tune, I'm actually trying very hard. I will Google test menu and try to figure it out. Thanks for the tip

FWIW 8% seems really low. Mine is closed around 20-30% and open before 60%, general reading makes me think mine's about average. It does weird things to the car going much lower than the closed value.

When I set the idle to warmup only the iac gauge in ms reads 8. Also when I run it closed loop it reads 17-18 when idling properly and 8 when hitting the gas or coasting. That made me think 8 was closed. I can always plug the air inlet when i think it is sticking and see if the rpms drop.

Warmup is a simple x/y for IAC% and CLT. You need to find the open and closed values using test mode then rescale warmup for your car. If 17-18 is your lowest desired idle RPM, that is closed. The idle set screw skews this, leave it be. Mine is closed... Learning open/closed values is a excellent fisrt step towards closed loop idle.

There's no need to go blocking stuff, if the car ran OK on the stock computer you should be fine.

The bottom line is: no it doesn't need coolant at all. Unless you're in like 30* and colder weather or something. So either your tune needs work, or your valve is bad.

My tune needs work. I'm going to print the whole megasquirt manual at work tomorrow. That should answer all my questions. Hopefully I get it to idle ok by the spring so I can gave it dyno tuned