Checking vacuum w/ gauge, need some help!

[yellowstang1994]

Search didn't yield the exact answer I was looking for. I'm trying to check vacuum with a vac gauge. I'm not sure exactly where I should hook it up to. I tried it on the tube that goes to the regulator, but got around 20hg at first then it went down to 15hg. Another ? is when I do this should I get like a 'T' fitting and hook the other end into it? Should I find a different place other then the regulator line ot hook it into? Help guys!

 

[DJHA90]

Im interested also.

 

[HISSIN50]

I cant remember if SN's have a vac tree like foxes do. On the 88, I connect it to a plugged port on the vac tree. I would not necessarily use the FPR line, as the change in fuel pressure theoretically changes the vac characteristic.

A tee makes it easy if you have one. A plastic Tee should be fine. Just grab manifold vac and you are good to go. 15-20" hg is pretty decent on a stockish motor.

Good luck.

 

[CManT1914]

I cant remember if SN's have a vac tree like foxes do. On the 88, I connect it to a plugged port on the vac tree. I would not necessarily use the FPR line, as the change in fuel pressure theoretically changes the vac characteristic.

A tee makes it easy if you have one. A plastic Tee should be fine. Just grab manifold vac and you are good to go. 15-20" hg is pretty decent on a stockish motor.

Good luck.

They do, on the driver side fender, right in front of the firewall. Correct me if I'm wrong, but doesn't the brake booster line carry vacuum? I let it suck my seafoam through there a long time ago. Other than that, there are a few vacuum lines coming off the back of the upper intake manifold that would work, they're just harder to get to. Good luck.
-Chris

 

[HISSIN50]

Yeah Chris, you are right about the brake booster (I used it to suck seafoam too).

Thanks for the vac tree info (it sounds a lot like a fox set-up).

 

[mo_dingo]

Disconnect the vac line that goes to the FPR FROM THE VAC tree, not the egr. Hook up the vac gauge to the tree and test it.

The vac reading should be stable. If you have an aftermarket cam, your vacuum readings will differ from what is printed in a haynes manual. If stock cam, should be right around the listing. It was for my car.
Scott