1987Porsche944WithRealLongName

I have no power going to my brakes so I was trying to mess around and see what's wrong and ended up getting a leak somewhere.. on top of my manual brakes.

Anyway I have a 951s engine in a n/a body with a lot of things deleted but this is pretty much exactly where I'm at now, down to the port placements. Can you see any reason why this wouldn't give me power to the brakes?

s14kev

Sweet picture dude!

1987Porsche944WithRealLongName

I got some smokes and started blowing into vacuum lines. Nothing is leaking except when I blow into the intake and smoke starts coming out of the filter. If I pull the hard pipe from throttle body to intercooler I see a lot of smoke coming from the throttle body plate.

Is there some sort of reason this wouldn't be sealing? Isn't the plate and body itself supposed to be pretty much flush without the need for any seals? It isn't coming from where the body meets the intake or anything.

CyCloNe!

from what I can tell that looks about what I have as far as vac routing goes.

Scott H

Is the brake booster holding vacuum?

Spidey944

Smoke coming from the throttle body seals is a common issue. Just buy a reseal kit, super easy DIY job.

1987Porsche944WithRealLongName

Pulled off the lines to the firewall and vacuum stabilized to 15"

I don't even want to know what all could be leaking inside the hvac stuff

Spidey944

I guess the simple diagnosis is, if you have vacuum going to the booster, stable or not, but your booster is not assisting during braking, then your booster is bad. If you unhooked the vac. going to the HVAC and your booster function returned, then you have found your problem.

1987Porsche944WithRealLongName

I should mention my afrs before now were lean, like in the 15-16 range. Then I repaired a BIG exhaust leak and rerouted my vacuum lines. I didn't have power brakes at this time either.

Anyway do you think my exhaust leak could have been giving a false lean reading the whole time when really I was rich all along? My plugs are blacker than black.

Spidey944

it depends on if your exhaust leak was pre or post turbo

1987Porsche944WithRealLongName

Should have added it was a plug in the crossover that was missing

Chris White

Exhaust leaks that are ahead of the O2 sensor can cause a lean reading at idle/cruise due to the O2 entering the exhaust. When on boost there is enough positive pressure in the exhaust that no O2 will leak in, only exhaust leaking out.

You diagram looks right – if you are not getting power assist then you may have a bad power brake booster – or you somehow installed the check valve backwards!

1987Porsche944WithRealLongName

Black goes towards the booster right? I'm guessing it somehow messed up when it was sitting as I can't get the thing to work no matter what. What's weird is I can do the test where you pump it until it's hard and then start the car and it always falls a little as it should.

I let the car warm up more and now I'm back to lean 15-17 idle
oh boy

pkt1213

Thanks for this. I realized when I was taking my motor out that nothing was connected to either of the vaccum line ports on the firewall. I have a LR kit to install when I get the motor back.

Van

I agree with Chris - blocked hose to booster, or torn booster diaphragm.