Stuttgart996

okay so i just pulled the engine on my turbo to replace the rod bearings and oil pan gasket.
now i have low vacuum around 10-12 upon start then going down to 5 when it gets warm.
along with this my afr is around 10 at idle.

i am trying to figure out what could be causing this. at first i though it was the intake manifold gaskets but replaced those today and still the same.

i want to do a pressure test in the intake just to make sure but dont know the proper way to do it.
here is what i have done
1. taken the maf off the j pipe and sealed the end of it.
2. i also took the line off in between intake runners 1 and 2 and sealed it with a battery.
3. i am blowing the air in with a air compressor through intake runners 1 and 2 and all i can hear is the turbo spinning. (do i have to take the j pipe off and seal the turbo right at the inlet?)

let me know any comments would be appreciated

chris

lart951

sell it to me

Ian Carr

chris is you want to drive down here I can take a look at it and see if i can help. I'm around tonight and tomorrow all day.

let me know

Stuttgart996

yea man that would be awesome i think i have a huge vacuum leak but cant find it

Spidey944

A rich condition can be caused by a vacuum leak any day of the week. With your vacuum and AFR readings, this would make sense. You would need a pretty good sized leak AFTER the AFM for this to happen. Start with all of the hoses you removed to do the bearings and opg. Sounds basic, but your problem should be related as your AFM's and VAC would not realy be affected by your repairs unless it's something you removed and never put back.

Ian Carr

Just head over here when ever, gimme a call first.

Spidey944

the real question here is, what kind of vacuum leak would get worse when the engine warms up?? Components will expand making a vac. leak better in most cases....

Bri Bro

The emission vacuum system goes through a temp switch that opens with temp.

Air leaks after the AFM (at idle) would add unmetered air to the mix and causes a lean run condition. When under boost, it causes air to exist the manifold (subtract air from the mix) and causes a rich condition. Do I have this backwards?

Spidey944

A vac. leak after the AFM would cause rich because the air/fuel ratio detected by the O2 sensor would be lean, thus the PCM would richen the mixture.

Ian Carr

dropping down to 5 in/hg means he has a serious vacuum leak, not just running rich.

Bri Bro

Closed loop mode would try and pull the mixture to 14.7/1. I read the mixture was 10/1. Very low vacumm reading.