Fuel Pump Inertia Switch

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Tom Brearley
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Fuel Pump Inertia Switch

Post by Tom Brearley » Sun May 10, 2020 9:20 am

I have been meaning to fit a fuel pump inertia switch for some time. The purpose of the switch is to break the circuit to the electric pump in the event of an accident. Such switches were fitted to late North American Bs.

There's a good Moss video that explains inertia switches here https://www.youtube.com/watch?v=o_K1h4PoMeQ

Once I had overcome my own intertia to get the job done, I sourced an OE switch from the States and fitted it yesterday. It is positioned behind the dash on the bulkhead, above the driver's left knee.

It seems like a worthwhile addition and one that might, conceivably, have been made 'in period' during the late 70s. I must warn anyone trying anything similar that access is awkward and will involve some swearing.

Tom
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1973 MGB GT (Exeter) - currently shaking down after 3 years off the road

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Tom Brearley
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Re: Fuel Pump Inertia Switch

Post by Tom Brearley » Sun May 10, 2020 9:22 am

The pump circuit is interupted just behind the ignition switch.
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1973 MGB GT (Exeter) - currently shaking down after 3 years off the road

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Tom Brearley
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Forename: Tom
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Re: Fuel Pump Inertia Switch

Post by Tom Brearley » Sun May 10, 2020 10:55 am

Conviently(?) one also gets a warning when the switch has tripped as the indicators don't work! This could perhaps be useful in the event of a very minor shunt or a bad pothole causing the float bowls to empty a few minutes further down the road.

(The white wire going to the fuse box is a spur off the fuel pump supply.)
1973 MGB GT (Exeter) - currently shaking down after 3 years off the road

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