The increasing vacuum in the tank is due to a plug in your EGR system,
there's a vent tube coming off of the filler (under the rear cowl, and
behind the fuel tank. you can (possibly ) get to it with a screwdriver from
there, but it runs to the left rear fender well from the filler neck. If
you want to test this, disconnect it from the charcoal canister in the left
rear fender, and drive it a long distance. The charcoal canisters, etc. of
the EGR system can become clogged after 20 some odd years of fuel (good and
bad) gong through them.
Mark Haynes
'65 SPIT RMVR#162
> -----Original Message-----
> From: Simmons, Reid W [SMTP:reid.w.simmons@intel.com]
> Sent: Monday, April 19, 1999 5:12 PM
> To: Ryan Smith; spitfires@autox.team.net
> Subject: RE: idle increase
>
>
> The idle on Spitfire started doing that many years ago. However, after
> the
> car was turned off for a while (overnight) the idle would be OK upon
> startup. What I discovered was that the tank was no longer being vented
> resulting in a vacuum building up inside. The longer the trip, the
> greater
> the vacuum. (I found this out one day when I popped the gas cap and was
> nearly sucked inside the tank by the vacuum!!) The fuel pump would have
> to
> "fight" against this vacuum for the fuel. My "idle" would oftentimes be
> well over 2000 RPM, and there was many a day that I ran with the gas cap
> released to avoid this. Oh yeah, it IS on my list of things to fix during
> the restoration project!
>
> Reid '79 Spitfire
>
>
>
> -----Original Message-----
> From: Ryan Smith [mailto:shmitty99@hotmail.com]
> Sent: Monday, April 19, 1999 11:51 AM
> To: spitfires@autox.team.net
> Subject: idle increase
>
>
> Yesterday, I drove the spit further than I ever had in one sitting
> (about 200 miles). No real problems to report except I noticed that
> now my idle is considerably higher. I used to idle nicely around 8-
> 900 or so but since yesterday I'm idling around 1250 sometimes at
> 1500. Any ideas on why before I start adjusting the idle screw. The
> timing and carburation were spot on before I left. I did adjust the
> valves before i left but I think the idle was still correct after
> doing that.
>
> thanks
>
> Ryan Smith
> 72 Emerald Green Spit... who's not happy to be leaving outside now
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