reno808

I like your drawing skillz

lee101315

Its pretty simple

Plug the little hose on the check valve and pull the big vacuum connector off of the booster with the car running.

You should feel a lot of vacuum coming through the big hose. If not, somethings wrong.

You should also notice a psshhhh noise coming from the booster when you disconnect the vacuum, thats air rushing in the fill the vacuum the booster is supposed to have.

If you have a good amount of vacuum going to the booster, theres something wrong with the booster

ausgeflippt951

I love this picture. Literally laughed out loud.

Gets the point across though! I support it 100%. I'm just glad you included a picture...too many people (myself included, at one point in time) have had a tendency to say "What's wrong with my vacuum lines?" and then not give any visual clues.

eman930

Where is your wastegate in the picture?? I see the BOV but no wastegate?, Also it sounds like you have a vacuum leak and that's why you how lean on the AFR, I'd try 2 things, first isolate the large vacuum line to the booster, so it's just that line to the booster, if still no power brakes then you have a bad booster.... Second I'd disconnect the line the goes to the inside HVAC setup and the boost and see if your AFR readings change then you have a leak in the HVAC or booster, then isolate from there

1987Porsche944WithRealLongName

I think I got my idle under control

When I drive and press the brakes I hear hissing from inside the engine bay. Seems odd that it would just randomly mess up like that but I really think my booster is toast.

Paulyy

1987Porsche944WithRealLongName

Went for a drive and came back to the house. Walked out 15 minutes later and unbolted the master cylinder from the booster and it equalized pressure through hissing. I also tried pumping air into it and doing a smoke test and not a bit comes out

Could a bad master cause a hissing somewhere within the booster itself? I haven't noticed any leakage.

My leanness is apparently intermittent too, but I'm tackling one problem at a time.

1987Porsche944WithRealLongName

Replaced the booster and I now have power brakes, thanks guys

Vacuum is still at 13-15 at idle though, I'll have to figure that one out.

968 GUY

Would bad AOS seals and/or cap cause a vacuum leak?

Reimu

I wouldn't think so since the AOS hose is before metering

1987Porsche944WithRealLongName

Took a can of carb cleaner and poured over the engine waiting to hear an idle change.

Nothing.

Scott H

Have you tried this and listened for leaks?

Van

+1