Vacuum leaks
 

As I was browsing the "Buying a Zr-1" I stumbled across this:
Check for a vacuum leak. Open hood, turn ignition key on but don't start the car. Listen for vacuum pump to come on which is located under front right headlight. It should come on only for a few seconds and turn off. If pump stays on or comes on every few seconds then you have a vacuum leak.

I noticed (with the key on and the engine off) an intermittent noise coming from under the pass.side headlight while waxing the car (90). It would come on a few times per minute, a second or two at a time. Secondaries and lines were replaced before I bought it. Could I have a vacuum leak? Car runs fine, no problems that i can tell.

How often is it? I'd think if it were like 30 seconds or more that this might be normalish? That's the secondary vacuum pump, though. Mine comes on for an instant about every 3 seconds... definitely leaking.

I'll check after work today;hope not, don't want to tear into it just yet.I'll post what I find tonight

So did you determine how often it comes on?
As was said it will cycle on now and then, but if you have it going every 15 seconds or so, it has a leak.

:cheers:

I haven't had a chance to check it, put it back in storage for the time being. I'll check it at some point this weekend, have to go get my stare on :mrgreen:

I just checked mine...it cycles every 35 seconds with the key on and motor off.

good to go
 

CAV looks like ur ok per scoob's check!!! good to go!!! :o

I'll check into it Sunday, let you know what I find. Thanks, Scoob!

I think over 25 seconds is good. When I first got mine it was cycling every 10 seconds or so. If you do have a leak it's not a panic situation but should be addressed. Just be sure to get all the parts you need (lines, gaskets)before you pull the plenum.

I replaced all of the vacuum hoses under the plenum of my '94 last year. My pump barely comes on at all, and the car runs great.