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Old 07-08-2019, 10:49 AM
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JHZR2 JHZR2 is offline
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Location: New Jersey
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Quote:
Originally Posted by Diseasel300 View Post
So how does the vacuum leak down from 25 to 15"? There's a small leak somewhere, but probably not bad enough to cause major issues.

You may have a check valve failed somewhere or a vacuum connector rotted out that leaks when under high vacuum.

The critical troubleshooting element....how's your vacuum with everything hooked up and the engine running? Lousy vacuum from the vacuum pump or a leaking brake booster will cause system-wide vacuum issues.
Nothing is a big issue, more just stuff that I can notice during operation.



There’s lots of ways it could leak. Question really is if some of them will naturally do so regardless. For example I read elsewhere that the AT modulator can leak down so long as it is slower than 15s. Not sure if that’s the truth or not, but I’d assume that would mean a persistent leak when operating. Obviously depending upon throttle, the VCV causes a leak/vent as well. Stuff like that.

Wasn’t sure if everything absolutely is supposed to hold tight at >20, if it is anticipated that it leaks down to a more shallow vacuum then holds longer, etc.
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