Re: V8 '165 harness modifications

["SPECTRO COATING CORP." <spectro@ma.ultranet.com>]

> | Why is there an oil pressure switch in parallel with the fuel pump relay
outp
> | ut?  Does the relay prime the pump, turn off and then when oil pressure
is bu
> | ilt up enough the pump is turned back on by the oil switch and no longer
the
> | relay?   If I have this wrong, could someone please explain to me the
sequenc
> | e of events?

Because GM doesn't use a impact switch on the fuel pump (Ford does).

The relay is energized from the ecm on startup to pressurize the system for
a quick start.

At that point the oil pressure switch takes over and supplies power.

If the engine should lose oil pressure - either by mechanical failure or as
in the event of an roll over - it shuts down the fuel pump.

Just a another method to protect the occupants in a crash.


----------------------------------------------------------------------------
To unsubscribe from gmecm, send "unsubscribe gmecm" (without the quotes)
in the body of a message (not the subject) to majordomo@lists.diy-efi.org