> The Facet fuel pump instructions strongly recommends wiring it to the Oil
> Pressure Switch (OPS) so that it won't pump fuel with the
> ignition switch on
> unless the engine is running. To quote them "This stops pump operation if
> the engine stops and the ignition switch is on." OK, now my OPS has 3
> terminals (ground, anti-run valve & Oil Pressure Light (OPL)).
IMO, the easiest/best way to make this work, is to use the anti-runon
solenoid connection to ground the pump (or the pump relay coil). The ARS
should still function as usual.
> Added to the
> mix is I have Dan's harness with 3 leads from the fuel pump relay: warning
> buzzer, inertia switch & fuel pump.
If you want to use an inertia switch, run the "inertia switch" lead to the
switch, then the other lead from the IS to the OP switch. Or if you choose
not to include an inertia switch, just run the IS lead to the OP switch.
> Am I misunderstanding how the OPS works on the TR6?
No, I think you've got it exactly right. To use the 'normal' contact that
operates the dash light, you would wire the fuel pump relay so the pump only
runs when the relay is not energized. This is possible with Dan's
powerblock (by exchanging the fuel pump and warning buzzer leads), but IMO
it's better to use the other OP contact, as above.
> Plus if they don't want
> the pump on until the engine starts, the only fuel the carbs get is what's
> sitting in the bowl. Right?
Only until the oil pressure comes up, which should normally be only a little
bit of cranking. The switch closes at a relatively low pressure, like maybe
10 psi, so it doesn't take much. If this is a concern, you can add a
push-button switch that temporarily connects the IS lead to ground, so you
can manually override the OP switch.
> How do you guys/gals have your electric pumps wired?
The one on my Stag has only the inertia switch, as original. I've already
managed to hydro-lock the motor, by leaving the key on with the engine not
running and having a leaky float valve.
The VW Rabbit I used to own had a small electronic circuit inside the fuel
pump relay, that monitored the signal from the points and only powered the
pump when the engine was turning. They had a reputation for being
unreliable, but I think that was mostly because the windshield always leaked
water onto the fuse/relay block.
> The only other thing I found in "googling" this OPS
> requirement is that it's required by the Coast Guard and FAA in
> boating and
> airplane applications. Maybe different for cars?
Well, certainly the Coast Guard and FAA have no "car" requirement. Our
automotive safety standards being what they are in this country, you can
pretty much do anything that suits you in this area.
Randall
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