Hey guys, I got the turbo installed although STILL burning the old oil in the cat, but I have an idle question.

This started doing this just recently. It doesnt want to hold an idle verry well. some times better than others.

Well I was listening for air leaks under the hood then all of a sudden I hear a "click" from around the air box area and then the motor idled fine. This isnt the first time I have heard this. I thought it was a syl. opening and creating an air leak. I cant hear one but when I hear that relay click it runs fine, then driving down the road it will try to hessitate at a low idle then be fine again.

What is this relay I am hearing? I cant take a pic of it because I didnt even know there was a relay in that area.
Any ideas on where to look so I dont have to tear the whole thing apart to find it?

thanks

 

On an S4 there is an air bypass relay up there in front of the airbox, is that the general area of the sound?

 

ya it sure is

there is a bypass relay? why the hell would they have one there.
that sounds exactly like the issue. What actuates the relay do you know?

 

The ECU activates the relay, which then energizes the air bypass solenoid, to bypass even more intake air (above and beyond the BAC valve) for heavy engine loads, such as a/c, steering, etc...

 

great thanks!
I dont know why they had to make this such a difficult process for an engine to run. idiots

also I found that the BAC plug is broke and it pushed the terminals out the bottom of the plug.
I am asuming with no connection to the BAC the air bypass valve wound make it run funny?

I need to read up a lil more on this BAC thing also the air bypass valve. cant a person just get rid of them?

 

What do ya mean, it's a beautifully engineered system, IMO. Gotta remember, I've been staring at aircraft electrical systems for almost 20 years now, so I know crappy design when I see it

Sounds like you need to fix that BAC first, I'll bet that'll solve most of your problems...

You can ditch the BAC systems, but then you'll just join all the other guys on this forum with idle problems...They don't suck horsepower, they're not in the way, they're there for a reason- keep 'em...

 

thanks again, I am currently reading about the BAC and their purpose.