Low Vacuum

[fastsvo]

I picked up a vacuum gauge from HF and started poking around.

Looks like I do indeed have a low vacuum situation (my low brake pedal situation brought me here). I am not sure if its the cam, a leak, old mass air tune, or a combo of multiple problems, but for your viewing pleasure I have taken a video.

http://s69.photobucket.com/albums/i45/fastsvo/?action=view&current=IMG_0019.mp4

I checked the one way valve at the booster and its good.

Where should I start looking?

Thanks!

[dagenham]

What is the problem you are having exactly??
Where did you have the vacuum gauge hooked up at???
What is your timing set at with the spout disconnected??
We'll start with those three questions and go from there.

[Patrick]

Is there anything vacuum related on the car that is not working properly? Blend door functions, and items that are supplied vacuum by the vacuum reservoir behind the right front fender are what I'm asking about. Some of those hoses or a plastic tee may be junk.

What cam are you running? That might make a difference as well.

[MikeFleming]

I picked up a vacuum gauge from HF and started poking around. Probably not very high on the accuracy list to start with, What numbers did you get on the gauge? Highest during driving decel? Lowest during idle? Steady or bouncing?


Looks like I do indeed have a low vacuum situation (my low brake pedal situation brought me here). A low vacuum condition would give a hard brake pedal, NOT a low one.

As others have asked: What symptom or problem are you trying to solve?

Cam profile and ignition timing will have a MAJOR effect on idle vacuum levels. Intake side air leaks will have a minor effect - generally with a resulting high idle condition.

[blueboss]

FWIW, I normally run +/- 15"hg on a bone stock engine. I'd say you're gauge is reading pretty damn close. Pay absolutely no attention to the informational areas on any vacuum gauge for they don't take into account the myriad of different settings that will affect it.

[fastsvo]

I connected the gauge to the nipple port on the upper intake manifold and I also tried the dedicated port for the power booster and it's neighbor....the results were the same.

The blend door works as it should, but sometimes when accelerating and in boost, I can get a rush of air coming out of the vents.

As for the cam, I am running one of Barry's (TurboAlpine) regrinds (my cam was originally an ETS .500 roller).

Looks like a lot of people have confirmed that 15" of vacuum is normal for the 2.3li, but my motor at idle always sounds a little weak when comparing to others 2.3li cars in person or on the 'net. I always assumed it was my big cam.


Thanks!

[blueboss]

The blend door works as it should, but sometimes when accelerating and in boost, I can get a rush of air coming out of the vents.


There is a check valve installed on the firewall, just above the factory pinchweld for the cowl cover and to the right of the hood hinge. If it's not there, put one there. If it is there, replace it. There should be a small diameter plastic line coming from the vacuum distribution tree connected to the end. A same type line coming from the heater core access hole in the firewall connected to one of the ports facing down and another line connected right next to the previous going out the rear apron access hole connected to a vacuum "storage" canister. Anyone got a pic?

[MikeFleming]

Anyone got a pic? Is the pope catholic??

Remind me later (about the pics) when I get home.

[MikeFleming]

Some related pics from assorted cars.

126012611262126312641265