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1983 280zx N/A
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Discussion Starter · #1 ·
I just replace a couple of vacuum lines (in pictures) and it fixed my a/c problems. But now when I turn the a/c off the idle rpm doesn’t drop back down, and after about 30 secs a terrible whine comes from the larger of the vacuum lines pictured. The best thing I can describe it as is that it sounds like one of those cheap plastic party horns. Anyways, when the whining stops, the idle goes back to normal. My guess is that it’s some sort of pressure relief system that’s malfunctioning, because if I unplug the vacuum line myself during the whining it fast forwards the process.
Any ideas?

pictures:
White Automotive tire Light Wood Bicycle tire

Motor vehicle Automotive fuel system Automotive exterior Automotive air manifold Gas

(the lines in question are marked in red)
Edit: fixed pictures
 

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It may be one of the related valves are not closing well. I think the one pictured is the FICD which goes to the magnetic switch (valve I believe) on the little vacuum tank.

Either the magnetic switch is not closing allowing vacuum to be applied to the FICD which causes the idle to stay high or the FICD is not closing properly once the mag switch closes and vacuum is no longer there.




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1983 280zx N/A
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7 Posts
Discussion Starter · #3 ·
Thanks for the help, I figured it out today. I had the lines from the vacuum tank to the intake manifold crossed. I switched the vacuum tank ends and everything works correctly now!
 
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