Should it be attached to the line that feeds the MAP sensor with a T? Any advantage here?

Or should I leave that line dedicated to MAP and attach with a nipple to the threaded adapter that feeds the brake booster?

 

leave the line dedicated to the map sensor. Any other connections made would mess up the sensors response. There are more manifold vacuum ports on the tbi. You could tap into the brake booster line, but every time you hit the brakes the fuel pressure would surge. Best to give the regulator its own line as well.

 

How do I know if the vac port is reg or ported vacuum? Just attach a vac gauge and if I see 14 inch at idle I am OK as a non ported vac? What is ported vac used for? 1995 7.4L TBI. thank you.

 

Ronny, hook it up to ported VAC. I also have a BBC TB. You can use one of the ports on the front. Keep the MAP by itself. To find ported, hook up a vacuum gauge to one of the ports on the front, car running at idle in park. 10-16 in of vac@idle (depends on cam), goose the throttle and look to see if the VAC drops of as engine RPM increase, if it does, use that port. The idea, is with higher vacuum at lower engine speeds, it will make the VAFPR keep FP low, as engine speed increases, and vacuum drops off (MAP goes higher), the FP will rise. I might be able to get a pic of what port I have mine run too.

 

What about the port that runs to the thermac valve? If you are not gonna use the stock aircleaner, wouldnt that one work??

 

The vacuum gauge check will work to find a full time vacuum port. Need to see vacuum at all times in order to use that port for a VRFPR. Even a small piece of paper over the port with the engine running can show whether there is vacuum or not. With vacuum the port will hold the piece of paper.

Note that on vehicles driven year-round the vacuum line should run on a downward slope toward the manifold. This is to help prevent condensation building up in the line and freezing.

Ported vacuum is used for the CCP system. This way it can not purge at idle, even if things aren't working correctly. The EGR & thermo-vac switch use manifold vacuum (full time).

RBob.