Re: what Rich Wagner said

["Eric H." <ejham@domain.elided>]

Rich Wagner observed this about disconnecting the O2 sensor, placing
the car in open loop mode:

"The mixture will likely go slightly rich, reducing power slightly,
decreasing Phil's fuel mileage slightly (both of these effects are
probably so small as to go unnoticed), and increasing his emissions."

I'm slightly confused about open loop mode and how the system enters
it. Is the shorting of the full-throttle switch leads also a way to
arrive at open loop? And if it is not, what is happening when this
switch is closed or the leads shorted together?

The reason I inquire is I'm encountering not reduction of power but a
great increase of power in the 1500 to 4000 RPM range. With leads
properly attached, the car has limited power under 4000. With leads
shorted, the car is all the way up the range. I am certain it's
running rich with shorted leads.

The fact that the engine has Sperry Stage 3 heads and what may be hot
cams has something to do with this phenomenon. The car has the stock
Bosch brain. Could it be that this setup has exceeded the range of
normal Bosch L-Jetronic delivery maps? The performance work was
performed by a PO, so some of the history of the engine is lost in the
mists of time.

Curious in Clearwater,
- - Eric Hambleton
1983 GTV6 -- Felicite

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