I wondering if disconnecting the electrical connector from the BAC would cause problems starting my car in the mornings that result in or look like flooding. After getting the car started and running, it starts fine through out the day.

The reason I disconnected the electrical to the BAC was because it's a bit dysfunctional and causes intermittent changes in idle speed usually when the car is not warmed up.

Thanks.

 

The BAC goes full open upon starting the car to add more air to the throttle body to help start the car.

 

Ok thanks.

Second question is about the BAC adjustment screw at it's front. If it's turned fully inward into the BAC what does that do as opposed to fully turned out?

I know my idle will decrease when turned in so that seems like less air into the throttle body. Is that correct?

My dysfunctional BAC needs to have that screw turned almost all the way inward to keep my idle rpms lower (1100) but still not low enough/normal.

Thanks.

 

Do you have a turbo or not? If not, there is no screw adjustment.

 

Non-turbo.

It's a nut that fits an Allen wrench at the front of the BAC. I can turn it and idle rates change. Seen posts about this months ago on the site but I'm not quite sure how they relate to my current problems. The reason I previously messed around with my BAC was the fluctuating idle problem. Posts said to clean the BAC and some mentions were made of adjusting this hex head screw.

Thanks.

 

The hex screw is not to be touched so chances are you fubared the BAC as the NA BAC is non-adsjustable unlike those found on the turbo model.

 

I kind of thought that's what you were going to say.

Is there some cheap hack or fix for this or do I have to buy used BAC? If I have to replace the BAC do you have suggestions on where to get one?

Thanks.

 

There's a for sale section on this board that you could use to source a replacement. It is possible though to lightly mess w/the Allen bolt w/o damaging the BAC but if you really screwed around with it then it could actually be damaged. I believe there is a spring inside that would become damaged if the bolt was turned too much. The BAC pulses open and then closed in repeated fashion. The spring has control over this flapping mechanism.

 

Would rebuilding it be an easy option? If so is there any instructions how?

 

I wouldn't know and I never read about it being done on this board either.

 

According to this thread there maybe some cutting involved so I can't really open it at least entirely for a simple rebuild.

https://www.rx7club.com/2nd-generation-specific-1986-1992-17/bac-removal-886512/

A post has a pic of BAC insides and I probably did crush the spring on the terminal side but I might be able to unscrew that hex nut and replace it.



------------

 

The thing is the spring has to be the right size and compression ability in addition to being installed at the right tension. Good luck.

 

If I can easily get a similar spring then isn't the right compression simply determined by voltage readings coming from the BAC or is there more?

The other issue is that I need to screw in that hex nut to keep my idle lower (1000-1100) but still not normal (750). Looking at the BAC schematic it seems that turning that screw into the BAC puts more closing pressure on the valve and this seems to mean something else is wrong.

 

The spring has a length to it, plus the thickness of the wire used would determine the compression ability to it so this has to be equal to the original. Secondly, since your BAC is likely damaged you can't use it to compare iy to a normal situation. If you disconnected the BAC and compared it to another properly running car that had its BAC disconnected also then you can make comparisons.

And since I've never seen replacing the BAC spring on this board you are entering virgin territory.