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mark houghton mark houghton is offline
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Join Date: Jul 2008
Location: Central Washington State
Posts: 3,893
Originally Posted by gsxrken View Post
When a decel valve no longer holds vacuum, what is the impact? Certainly, it won't open when it should to do whatever it does when it's open, but does a leaking one constitute a vacuum leak, so that removing a bad one would be better than than leaving it connected?
Is that why Mark may have picked up some response?
Most likely. If the diaphram inside were to spring a leak, both scenarios as you've described might be likely. You would be sucking in un-metered air anytime vacuum was present, and leaking out pressurized air when on boost. Bad scenarios, both.

All these redundant and basically unnecessary things that can fail - including the temperature sensitive ignition advance valve, can cause real gremlins that are hard to trace down. My motto: Do away with them unless absolutely necessary. I'm about as stripped down of that useless junk as I can be and tuned almost as good as it gets with CIS. The next step would be to save serious pennies for EFI....but, now that I've got the CIS all figured out (well, almost, with the help of everyone here), I wonder just exactly what the payoff would be if I took the EFI leap?
Mark H. 1987 930, GP White, Wevo shifter, Borla exhaust, stock everything else. The result of a massive Pelicanite good will fire recovery effort. Truely an open book, ready for the slippery slopes to modification.
Old 09-30-2010, 09:26 PM
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