Hello guys,

I THINK I might still be suffering from an air leak or something causing my car to run lean idling.

The car is a 92 NA 1.6L, pieced together turbo with intercooler, AEM UEGO air fuel meter, RX7 460CC injectors, Megasquirt PnP.

I had a vacuum leak I found which was a nipple under the throttle body hidden behind a bracket which I think goes straight to the intake manifold.

I seems like all intake manifold side leaks are plugged, I can't hear or see any, yet my AFR at idle is still high with injector specific required fuel settings (18-20:1).

So now I am turning my attention to the valve cover breather, I have the PCV on one side and slapped a basic small air filter on the exhaust side breather, will this be the source of an air leak? My turbo kit doesn't have anywhere I can route the valve cover breather back into via a tube :(.

I'm just trying to found the source of my high AFR, my idle is some what smooth, I hover right around 900-950rpm which I think is an acceptable fluctuation, I haven't driven the car in a while so I don't remember.

BTW I haven't put the car on the street yet, I was trying to straighten out this idle issue and make sure I am 100% fluid leaks free.
Thanks for reading, and any help.

 

What would make you believe it's vacuum related and not the tune that is the problem. Idle is one of the trickier things to tune out for the first time.

 

it might not be a vacuum leak at all, but I want to make sure I cover all my bases.

There was a vacuum leak I over looked which I fixed, but I am curious is the breather on the valve cover can cause a vacuum leak on the 1.6.
If it can't then I know I have all my leaks squared away and I will start playing with the fuel tables and adding more fuel around the idle kpa.

I think I can still hear a leak because I hear a faint hissing noise, but I dunno if it's from the spinning belts, or something else.

 

having the valve cover breather open like that will not cause a vacuum leak. do you have a boost vac gauge? i pull 20inmg at idle

 

did you do any tuning when there was a leak?

 

I did, but once I noticed I did have an air leak, I stopped tuning, fixed all air leaks, and reloaded the base map again to start from square one.


I don't have anymore air leaks now, am pulling about 18 psi in vacuum (I think my gauge reads vacuum in psi as well).

and I started retuning with no leaks.