I've done a search and come up with nothing. Got my Blitz BOV installed the other day and I'm running a little bit leaner than with the stocker. Made sure all hoses are tight and plugged the "new" hole in the TID. I'm still at 14.7 air/fuel but with the stocker it was more like 14.5. Why would a BOV make it run lean?

Any ideas please, thanks.

BTW: Only other engine mod right now is a K&N OEM air filter. And car is an S4.

 

you dont have to but it will probley help if you blew the air back into the TID

 

Is it vented to the atmosphere? If it is it should read richer. Did you properly adjust the bov?

 

It is vented to atmosphere. I could blow the air back into the TID, but if I did that I would have stayed with the stock value. This happens more so at idle. I have also read that the Blitz leaks vacuum?

Stupid question, how does one adjust the BOV correctly?

 

Wide-band?


-Ted

 

Sorry no. :-(

 

Then your readings before and after are inaccurate. Those cheapy digital A/F gauges are good to make sure the stock O2 sensor is working correctly but can't be relied upon for any tuning.

 

It is normal to run run lean if the valve is opening slightly at idle. A slightly open valve at idle will suck in air that has not been metered by the MAS, causing a lean condition. Vented to atmosphere, it will run rich between shiftsbecause it will be expelling air that has already been metered.

 

"Slightly open value".....??? I'll tighten the spring and see what it does. Any way to know what the tention on the spring "should" be?

 

Try loosening the spring until it is leaking at idle and tighten it 1/3 of a turn.

 

If you are not using a wide-band, your AFR numbers don't mean JACK.


-Ted

 

I'm taking the numbers with a grain of salt. I'm really only comparing the AFR reads before and after the BOV install. After the install they are a little leaner.

 

You shouldn't worry about it bc the readings on your stock O2 sensor really mean nothing. As long is it cycles normally forget about it.

 

I'm assuming goes more rich as I stomp the gas. Correct?

 

Your O2 sensor being a few degrees colder would also explain why your AFR gauge is showing leaner.

Serious, a narrow-band AFR numbers do not mean anything, even in your case.


-Ted