I recently found that my vacuum chamber (next to the power steering pump/under alternator) doesn't hold vaccum. I was wondering what it supplies/stores vacuum for, and what effects it leaking could cause? Any one had this happen? I've been having low primary boost issues and wonder if it may have anything to do with this. Thanks for any help, Evan

 

It's definitely an important part of the system. I repaired one some time back that simply had the nipple on the reservoir broken off. That's really the only failure mode I could think of for it - it's a pretty solid piece, and it's out of the way.

With the broken nipple, I just drilled/tapped a 1/8" NPT hole, and screwed a brass fitting with a hose barb into it. Looked and worked perfectly, cost only a few bucks, and was easy to do.

I remember it was a bit of a chore to remove the tank - I believe the alternator and the oil filler neck has to come off. Don't quote me on that, though - it was years ago.

Dale

 

Problems with that chamber are usually associated with secondary boost. There are several threads around about that chamber filling up with oil, thus causing secondary boost problems. Here's one:

https://www.rx7club.com/3rd-generation-specific-1993-2002-16/vacuum-chamber-filled-oil-199724/

 

Thanks for the link Kyle. I searched around a bit myself but couldn't really find much about people experiencing failures. The nipple on the chamber is fine, I just vacuum tested it and it slowly leaks after about 4-5 seconds. It's old, looks like the heat has just gotten to it over time. Well I'll replace it and see what I get and post the results some time. Thanks again guys.

 

No problem.

If you are having problems with low primary but good secondary, I would start by looking at the charge control system.

 

Careful with the nipples on that box. When I picked up my 92, it wasn't boosting properly. After searching this forum I got a vacum diagram & then found the box was the cause.

Problem was a broken nipple extending from the box into the pipe. Appears some one has been enthusiastic & cracked it at one time pulling off/putting on the pipe. Since these things are coming up on 13 years old, its no wonder they are getting problems.

With proper sealing, I now have full twin turbo operation.

Now for the 99 nose ..........

 

I've got a brand new one still in the wrapping if you're interested.

I thought it was the problem on my car.... found out too late as I had already ordered it.