Ignition-switched supply

PostPost by: stuartgb100 » Sat Sep 19, 2009 4:55 pm

Looking to wire in an electric fuel pump.

Before I pull a new wire back into the boot area, is there anything there
I can hook into ?

Regards and thanks,
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PostPost by: frearther » Sat Sep 19, 2009 7:49 pm

I ran a new wire rather than relying on the already-too-small wire back there. It's not hard to go under the carpeting and into the trunk/boot. I also added a ground from the fuel pump to the chassis for the same reason.
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PostPost by: RotoFlexible » Mon Sep 21, 2009 11:58 am

frearther wrote:I ran a new wire rather than relying on the already-too-small wire back there. It's not hard to go under the carpeting and into the trunk/boot. I also added a ground from the fuel pump to the chassis for the same reason.

I ran my electric fuel pump with a dedicated wire from the ignition switch to the boot for many years without difficulty. As part of my recent rewiring exercise, I ran a new wire alongside the regular body harness (runs in the left-side sill), and fed it from a relay rather than directly from the ignition switch. The relay is controlled by the ignition switch terminal that feeds the coil. I also fused the fuel-pump feed.
I try not to run components with a significant current draw - headlights, horn, fuel pump, heater fan etc. - directly through the old switches. Relays were designed for such tasks.
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PostPost by: 69S4 » Mon Sep 21, 2009 1:15 pm

RotoFlexible wrote: As part of my recent rewiring exercise, I ran a new wire alongside the regular body harness (runs in the left-side sill), and fed it from a relay rather than directly from the ignition switch. The relay is controlled by the ignition switch terminal that feeds the coil.



That's what I did when I put the electric pump in about 20yrs ago. Relay is mounted under the cardboard panel that goes across the back by the lights with a direct feed from the battery and an in line fuse. Pump is mounted in the small space between the fuel tank and the wing - on the right as you look at it from the back. It's been totally trouble free since it was put in.
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PostPost by: garyeanderson » Mon Sep 21, 2009 4:07 pm

Hi Stuart

On the S2 the GN (green/brown) wire is not used, (reverse lamps). I put that to the switched side of the ignition and used that for the fuel pump. Up front on the dash I used the heater blower switch as a kill switch as the heater was omitted during the build. I don't know what you are working on so can't comment further but I would want a dedicated wire for a fuel pump, maybe that's just me though. I still need the bump switch to make it a bit safer, one day I hope it will get done before it bites (burns?) me.
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PostPost by: stuartgb100 » Mon Sep 21, 2009 4:51 pm

Thanks all for the replies.

I've run a dedicated 17amp rated supply from the fuse box (ignition-switched)
through the cabin (for now) and into the boot via a gap between the rear screen
and the parcel shelf (another job for another day). I've fitted an inline fuse.

I'm going to order up 1 maybe 2 in-line manual kill switches and am also doing a
bit of research on a fail-safe fitted to the very last + 2s. I believe it was one of
the things Lotus did towards the end of the Elan production run when safety
became a bit more of a legal requirement.

I don't yet have a +2 parts manual, so if anyone can give me a heads-up, it
would be much appreciated. I'm told it's clearly detailed.

Regards and thanks again,
Stuart.
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PostPost by: Galwaylotus » Mon Sep 21, 2009 6:11 pm

RotoFlexible wrote:
frearther wrote:I try not to run components with a significant current draw - headlights, horn, fuel pump, heater fan etc. - directly through the old switches. Relays were designed for such tasks.

Hear! Hear!
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PostPost by: HardTop » Tue Sep 22, 2009 3:18 pm

some people use an oil pressure switch as a safety device. engine stops fuel stops.

perhaps an inertial switch out of a modern saloon car would be better
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