Ken,
I'll take credit for misleading you. If your vacuum retard isn't even
hooked up, this isn't the problem. When the vacuum retard is working,
it retards the timing at idle several degrees which lowers the RPMs by
several hundred. On my car, the vacuum retard unit isn't getting enough
vacuum to retard the timing when the engine gets a little too hot, so
the idle stays up around 1500 RPM. I traced the problem to the thermal
vacuum valve on the radiator hose leaking when it gets hotter than
normal.
I considered just disconnecting the retard, but I can't get my idle to
drop below 1200 without it (at least not without retarding the whole
timing curve). Also, I can set my timing at 2 deg. ATDC at idle, but
once the throttle is opened it jumps to 10 BTDC (due to the retard unit
losing vacuum). This keeps the emissions at idle respectible (maybe
only a concern in areas with emissions testing) without really hurting
the performance.
Joe Seward
Shapiro - Kenneth J. wrote:
>
> My car keeps bumping up the RPMs once it gets warmed up (GT6+)..
> like to 2,000. Anyway, one on the group suggested the vacuum
> retard (I've got the Delco with the dual function vacuum) could
> be the problem...had been with his TR6. So, I went out to check
> mine, and it's not even connected. How critical is that doo
> hickey?
>
> ken
> 1970 GT6+ KC81872L
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