I know there is a boost sensor on an N/A, and my question is.....
I ahev removed the A/P and ACV, and now the vacuum line that goes to the boost sensor is blocked off (I'm pretty sure anyways) because of the lack of ACV. (Just a plate covering the hole) The car seems to run just fine (a lot better actually) Do I need input from that sensor? Should I tee the line into another vacuum line or something??
Is my car going to turn into a cataclysmic fireball, or worse yet, a Honda?

(Oh, I posted this in 2nd gen tech forum too... sorry, I just need a reply soon!)

 

You should hook it back up.

 

To what? A Vacuum line or something? It is hooked up to the original connection, but inside, it dead ends at the inside of the block off plate ... I think. It is a dead connection without the ACV valce in place... right? I could be wrong, but thats the way it looks to me.

 

A vacuum line. The acv just provides a path and a nipple for the boost sensor. Its a straight shot thru the acv to the feed hole.. I only have a 87. When I do put a blockoff plate on , there are unused nipples on the intake manifold that I use. Use the nipplle the cruise control went to or tee into that nipple if in use. Some who make block off plates put a nipple on the blockoff plate where the hole for the original nipple was. If you car is anything like a 87 you'll find a couple of unused nipples with caps on them.

 

Thanks.... Mine is a little differen, the nipple isn't on the ACV, but above it, it goes down through the ACV though. Well, at least now I know it needs vaccum. I will hook it up ASAP.
Anyone know execatly how the thing works and why its there????
Thanks again.

 

Six Rotors, Irv, the father of his son Keith, and Gibson the owner of www.fc3s.com, can all give an answer that makes sense. I can give you a rambling answer. The ECU takes readings from several sensors like the afm, air temp, water temp pressure sensor, atp to make a decision on what the air fuel mixture should be. You already know that so if I were you I'd just pm one of the above if they do not respond to this post. I've got to stop writing on this site. Its some kind of addiction that I've got to rid myself of. Theres work to be done on the house. Have fun.

 

The boost sensor detects the intake manifold pressure(mostly vacuum in the case of the N/A)and sends a signal to the ecu.The signal is used to correct the basic fuel amount injected typically under heavy load conditions.There is also an atmospheric pressure sensor down by the ecu and it's signal is used to correct the basic fuel amount at higher altitudes(less air ,less fuel required).
As far as the vacuum port on the N/A is concerned,I know that on the 86-88 cars the nipple goes directly into the manifold above the ACV.So when you put the blanking plate on instead of the ACV you still get the correct signal.I would assume it's the same on the 89-91 cars.On turbo cars it is different.

 

even with the block of plate there the nipple that the boost sensor vaccum line orignaly hooked up to should still be functional. if you put your finger on the nipple when the car is running you will feel it sucking, and should here is sucking. if you did not cap it off you should have a bad idle. just hook it up to the orginal location, having a block off plate in place of the ACV will change nothing