ehall

What is/should the vac pressure read(on my zeitronix) in lbs of pressure? What is normal or average? Mine used to be about -19 to -21.x. It is now between 14.6x and 16.x. The turbo is spooling late.
TIA

Bri Bro

20inch vacuum at idle. Sounds like a small leak.

ehall

Thanks Brian!

ehall

When I come off of hard throttle, it goes back to 20.X, but then settles back at about 16. For the life of me I still can't find the leak. Any ideas?

AScholtes

Mine pulls about 17 at idle as well... but it has 254000 miles on her....

JohnKoaWood

Mine pulled 16... before I tore her apart!

Bri Bro

Vac line to the front of the throttle body, line to diverter, oil filler, vac lines inside the car for heater/AC, connection to the wastegate, idle controller, lines to fuel canister purge lines.

Might have to do a pressure test.

Ben951S

So wait on warm idle I should be at 20inhg?


I only hit that coming off acceleration....

ehall

oil filler?

Tom M'Guinn

I had 16+ on the old (worn) motor, and get 18 on the new motor -- that's fully warmed up. With an aftermarket cam, those numbers went down quite a bit. Don't ask me why, but I've noticed the vacuum varies a bit with the ignition timing and AFR also...

onspeed

I see ~16 when my AC is on. 20 when off. Fully warmed up.

Also, altitude differences might have an effect too.

Darwantae951

I pull about 19 at idle, and around 24-25 in/hg when decelerating.

ehall

hmmm...prior to changing out the head and HG, I was at 20 ish. Same bottom end and I'm at 14.X to 16.X. The car definitely seems to be running rich. I'll know AFR's tomorrow.

Tom M'Guinn

Probably just have a leak somewhere, but check the tune and make sure your cam timing is correct too...

ehall

That's what I'm thinking. I'm thinking that timing is a tad retarded.