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MG MGB Technical - Inertia Switch Question

I have a 77 MGB that I has been sitting for several years and I am in the process of getting it to run. I have replaced the battery and now the engine turns over and gets a spark. The problem is that there is no fuel getting to the carb. I was reading in the Haynes manual about something called an "Inertia Switch" on the bulkhead under the dash. I think I found said cylinder next to my steering column. Question is...should the button be up or down?? And would this be my problem with the fuel pump not working??

DQ
David Quigley

David,
What I had to do is to get an Ohm meter and check the switch. In my case the connectors are at the bottom.
Steve
Steve B.

David,

What I did was by-pass it. In many cases the inertia switch actually starts to leak. You can buy emergency fuel cut off switches through Vicky Brit or Moss if you feel the need.

Good Luck,

Luis
Luis

There are two fuel cut off switches on the car. One is under the dash that cuts the power to the fuel pump, and I want to say that the button is down for it to allow power to the fuel pump, but I could be wrong, it has been a long time since I messed with it. It is easy to bypass, just connect the two leads leading to it.

The other cut off is in the engine compartment on the fuel line and cut the flow of fuel to the carb. This one is usually missing as they had a tendancy to leak and most people have removed them.

If your fuel pump is ticking then the switch under the dash is in the right position. If it is not, you might also have a bad ground to your fuel pump.
Jayme

The inertia switch should be mounted on the bulkhead - just to the right of the knob of the hood
release cable. Perhaps the original screw mounting holes are still there on your car.

It is oriented vertically and positioned so that the button is "up" and the wire terminals are "down".

Push the button to reset the switch.

You could by-pass rule the inertia switch to rule it out as a problem source. Simply disconnect the
two wires at the inertia switch and connect them together, and turn the ignition switch "on".
Daniel Wong

Thanks for the info....I am just starting to troubleshoot this problem and forgot to mention that the licence plate lights do not light up....is thas a problem with the smae ground connection as the one for the fuel pump. If that is the ground for the fuel pump what is the connection that is screwed to the inside of the trunk at the pump itself?
David Quigley

This thread was discussed on 29/10/2001

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