IACV question with a twist :)

[heywier427]

S13 Sr20det in Hardbody. Big hp's

Swapping in a Freddy intake manifold, and cleaning up the bay. While doing this, I deleted/welded up the 2 lines off the coolant pipes going to the iacv. I know, stupid me. Should not have done it, just moving too fast.

Question. Can I just run a intake vacuum line to the in and out ports on the iacv. I think it will see hot enough temps to close it like this. I put a heat gun to it at the low setting, and the valve closed pretty quick. I did not test the temp, but will tomorrow with my ir gun.

Its coolant lines, so I dont think seeing 20-25psi can hurt it.

Whadda ya think.

I know I can just weld the 2 nipples back on, but Im lazy...

Thanks.

And I want to keep the iacv, as I have ac. Unless there is another way to control the idle bump in the ecu.

This was another idea: Just force the coolant part shut all the time, and rely on the valve to regulate idle, even when cold. Will it adjust enough when fully cold...I dont know.

Nissan saw a need for it, so maybe it will not be enough of a vacuum leak if shut when cold. It is a pretty big hole (+/- 3/8"), as compared to the iac piston part which is less than a 1/4"

Thanks.

[heywier427]

So been reading for a bit. Alot of guys say you do not need coolant running through the iacv. I find this very hard to believe. If no coolant heats it up, that huge 3/8" vacuum leak is always there. Theres no way thats right.

Another idea came from some one who did the same dumb thing I did. Their idea was to use the small coolant port that "went" to the throttle body. But not have it loop back into the system. It would just run to one port of the iacv, and the other side of it would get capped.

Down side is it will take a bit longer for it to get up to temp, as the coolant isnt flowing through it. But it will still happen.

I think I can deal with that.

[Kingtal0n]

The hole when cold is for raising idle when cold.

Simply block the hole or limit total airflow.

For example if you went to homedepot they sell ball valves,
you can install a ball valve and restrict the total airflow into the IACV manually so it never uses more air than some maximum allowed you decide on.

Alternatively block the hole completely so it never works.


The down side is the idle will be low when cold. Which isn't an issue if you are an experienced enthusiast/mechanic. The high-cold idle is more for drivability of sheeps that always expect their cars to run absolutely perfect like factory. It might stall on them or hesitate when cold, but we don't care because we know how to handle that.

[heywier427]

Thanks. I chose to run the single water hose to it, and cap the other side. Should be fine. Only time will tell. Winters coming fast! Hurray!!!...