Date: Fri, 17 Aug 2001 21:10:58 -0400
Reply-To: Bill Harris <biharris@CASAGRANDE.COM>
Sender: Vanagon Mailing List <vanagon@gerry.vanagon.com>
From: Bill Harris <biharris@CASAGRANDE.COM>
Subject: Re: do we have a vacuum leak?
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Sometimes it helps to see if the idle smooths out by stifling the air intake
a bit (a hand covering it partially should do the trick). This usually
indicates a vacuum leak and could save a wild goose chase if it's something
else...
bill
----- Original Message -----
From: "Scott G. Terry" <sgterry@ENGINEERING.UCSB.EDU>
To: <vanagon@GERRY.VANAGON.COM>
Sent: Friday, August 17, 2001 10:18 PM
Subject: do we have a vacuum leak?
> Hi Michael,
>
> Thanks for responding to my post. I'll be interested to read your
results.
> Please carbon-copy me when you post them to the list. I subscribe in
> digest-mode and don't always have time to keep up with the traffic.
>
> Pearl is fluctuating rapidly between 7-9" vacuum at idle so I think by
> anybody's standard I do have a leak. Lucky me!
> I think I can hear a leak but I can't get the engine to race when I hose
> suspect areas with carb cleaner (not the safest approach, use cat.
> converter safe brand, etc. etc.). Maybe a worn valve train... maybe I'm
> just hearing induction noise...
> this is where experience (which I lack) would really help.
>
> So is 10-12 " indicative of a healthy vacuum or a leaky vacuum? I believe
> the question remains unanswered. My conclusion from my test was manifold
> vacuum should be 15". Yet no one has stepped up to the plate and said
> they're getting 15" in their wasserboxer. Matthew Pollard is getting
> awesome gas mileage in his 1.9L(?) and I think I remember that he brought
> his fuel pressure into spec with a new FPR, so this would imply his engine
> has good manifold vacuum. So, Matthew, how about borrowing a vacuum gauge
> from UI and measuring your manifold vacuum at idle (and maybe 2000 rpm
> while you're at it)? We would make you second author if we publish the
> findings in the Journal of Vanagon Vacuum (J. Van. Vac.). First author if
> you also do some NMR on the head gasket adhesive and solve the riddle of
> the water leak.
>
> Scott Terry
> '85 Westy "Pearl"
> Santa Barbara, CA
>
> >While attempting to evacuate my AC system, I noticed the MV as 10" to 12"
> >Hg just as you state. Do you think I have a leak somewhere -- I hadn't
> >thought that it might should be 15".
> >
> >Thanks,
> >Michael Townsend
> >90 Carat
> >Durham NC
> >
> >PS. Finally got my R-134a charged this morning -- looking forward to a
> >cool drive home!
>
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