Strange problem, maybe vacuum leak?
#1
Rotorhead for life.
![](https://www.rx7club.com/images/misc/05_year_icon.png)
Thread Starter
Join Date: May 2002
Location: Arizona
Posts: 340
Likes: 0
Received 0 Likes
on
0 Posts
![Angry](https://www.rx7club.com/images/icons/icon8.gif)
I just got done porting my manifolds and when I put everything back together I kept getting leaks at the manifolds. This happened like 6 times so I took everything back apart and thought I finally had it fixed. Now, with my A/C ON, the car idles perfectly. But it I turn the A/C off, the idle jumps around and the engine becomes very shaky. I would guess its a vacuum leak because of the freakin manifolds, but what the hell does the A/C being on or off have to do with it?
#4
Lives on the Forum
![](https://www.rx7club.com/images/misc/05_year_icon.png)
I answered this earlier in another thread- when you turn the A/C on, the ECU energizes the air bypass solenoid valve, which routes a bunch of air around the throttle plates to help support the idle with heavy loads on the engine. Unlike the BAC, which "cycles" on & off several times a second to adjust the idle air with precision, the air bypass solenoid is an "all or nothing" valve, i.e. open or closed. In any case, to the point- this is conjecture on my part, based on educated assumptions- once the ABPV is open, so much "extra" air is routed into the intake system, that any small vac leaks become insignificant in comparison...My theory, take it or leave it
![Smilie](https://www.rx7club.com/images/smilies/smile.gif)
Trending Topics
Thread
Thread Starter
Forum
Replies
Last Post
troym55
3rd Generation Specific (1993-2002)
23
05-25-16 12:42 PM
gabescanlon
3rd Generation Specific (1993-2002)
4
09-05-15 12:04 AM