After I installed a crankcase breather filter, my a/f ratio at idle went from 14.7ish to up to more than 19ish, 20ish, 21ish a/f ratio. Reason I installed this is because I was planning on supercharging. I think it also increased my a/f ratio at WOT. AnywayIve already checked for vacuum leaks and found none. Also it feels like the engine wants to stall and idle bounces around a little bit more than it used to. Reason I posted is I wanted to know if it safe to to idle at this a/f ratio or do I need to put the stock hose back. I'm not really worried about the a/f ratio at WOT because I have a safc 2 to take care of the leaness, just worried about the idle a/f since I cant adjust, because its in closed loop.

 

you know what, i tried this before...took off my midpipe and ran straight from the MAF....in other words, the crankcase hose was just dangling down....and my AFR went wacko as well....i didn't really get to go on a full test drive...but from what I was able to observe, my idle AFR was super lean like yours...and low cruising RPM was lean as well...not sure about WOT...

btw, which wideband do you have?

 

try putting the stock hose back on. If your A/F goes back to normal, then the new setup must be causing the leaner ratio. If you put it back on and its still up there, then its just a matter of figuring out what causing it.

 

you do realize that its a vacuum hose. everyone always thinks its a breather even i did and then my max started idling like it was missing lightly. i put my finger over the hose and yup vacuum.

 

sorry for the ignorance...but that hose is a vaccum hose? i thought that hose was to push OUT crankcase ventilation?

 

Hello Mcfly! Its connected to the IM via the PCV. This creates a huge leak. You have to put a breather on the PCV for this to work correctly.

 

i have a zeitrinix wide band. I already know that this is also a vacuum, which is probably why a/f is high? because of unmetered air right? What I wanted to know is if it safe for my engine to idle like this.
Also curious about the pcv thing. So does this mean if I put another filter at the pcv the a/f ratio would go back to normal?

 

the breather has been done a million times, i have done it in the past. no one to my knowlege has had any real issues from the single breather. then again not many have an a/f gauge to even know its bad in the 1st place. it creates a huge leak.

yes the 2nd breather will work as long as you plug the port on the intake manifold. this is the correct way to do this. if you dont disconnect both sides of the pcv system you will have problems.