Boost leak through IAC possible?

[douglas vincent]

So I am getting even worse bucking now (sometimes) than I was before with my old intake manifold. However, it feels very different as well. Like the boost is leaking out on and off. Could this be leaking through the IAC?

[vrg3]

It's possible. There's supposed to be a check valve built into the IAC valve, I think... but maybe not. You could try just putting a check valve in the IAC hose.

[douglas vincent]

Check valve, check!

It needs to be a big one if I were to match the 3/4" stock hose.

I am going to mill an adapter plate so I can use the old stock IAC (2 wire).

I also might just block it off and see how bad it runs. Last resort.

I suspect that I am, for sure, getting some weird boost leak for sure through the current "new" IAC because if it is not working right to start, then it very well may not be closing when it should, or at least holding the boost in!

[vrg3]

They do sell check valves at hardware stores for a few bucks that would probably fit. The cracking pressure might be higher than ideal but it may work.

[Legacy777]

The turbo legacy has a little flapper check valve.

However, I'm not sure that will work on the n/a manifold.

[douglas vincent]

Not the IAC. I rerouted it to be post SC so that if it were to leak, it would leak back into boost, which therefore would prevent it from leaking.

I also fabbed up an adapter plate and am running the old 2 wire IAC. Still weird idle, but the IAC is working.....

But, I hate this shit. I was able to barely tolorate the old bucking/missing. But now its worse, and I even tried removing the SMT6. And its still therre!!!!!!!

I thought it might be a leaking at boost Air Bypass Valve. Nope.

Now I don't know what.

I am replacing the battery tommorrow on a whim ( I have killed it dead about 30 times) and I may replace the coil and ignighter while I am at it.

[Legacy777]

Try resetting your ECU as well.

[douglas vincent]

Spark plug wire. Stupid.

I went to change out the spart plugs today with new ones gapped to .035 and look down to see #4 isnt even connected. Hmmmmm.

I must have done something that loosened it when I installed the FMIC and it slowly worked its way loose.

Wagon runs alot better now, imagine that.

[napphappy]

Cool, glad to see it was something simple.