GM Fuel Pump control scheme

[Bruce Plecan]

And you would explain the Vega, how?.
Bruce



From: <WEG1192 at aol.com>
> To me its obvious that Steve Ravet was right in that the OP switch is used
to
> keep the pump running during CPU failure, otherwise limp home wouldn't
work
> period. I can also say for certain that the ECM keeps the pump running as
> long it recieves ignition pulses from the distributor. To say that the OP
> switch is a backup for the F/P relay doesn't hold much weight to me. Also,
> the OP switch isn't a safety to shut down the pump since if the engine
stops
> with the key on, the ECM will shut the pump off due to the lack of
ignition
> pulses. The only plausible resaon left is to keep the pump running during
> limp home mode. JW

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