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thingy in the boot - a silly question
SierraL_killer - 20/12/06 at 12:06 PM

Hello, im stripping my sierra donor and ive found a thingy in the boot where the spare tyre goes. Its wired up to the fuel pump and appears to have a switch on it - what is it and will i need to keep it?
Cheers

mcerd1 - 20/12/06 at 12:09 PM

Its the crash/ impact cut-off for the pump

02GF74 - 20/12/06 at 12:09 PM

wiring for the flux capacitor?

Bluemoon - 20/12/06 at 12:10 PM

might be wrong but I think it's the boot lid switch (i.e for a boot light), and it shares and earth with the fuel sender/pump

[Edited on 20/12/06 by Bluemoon]

nludkin - 20/12/06 at 12:16 PM

It's an inertia switch... In the event of a crash, it breaks the circuit and stops the fuel pump. You can then press the white switch on top to reset it and allow everything to work again. I don't believe it is essential to fit one for SVA, however, I have wired one into my car for safety.

mcerd1 - 20/12/06 at 12:19 PM

I've heard of people bumping it when taking the spare out - then wondering why the car won't start

the_fbi - 20/12/06 at 12:22 PM

I believe for fuel injected cars its required for SVA.

goodall - 20/12/06 at 12:35 PM

there was one on our old xr3i took the whole efi kit of the engine, the cpu and the fuel pump out and replaced it with the same stuff from a donor car still the car didn't work, turns out it was this swtich which none of us knew even existed as you can imagine we felt like the right idiots after doing all this. its just abit of wireing if i were you i would fit it just to be on the safe side if not for the sva just in case you do have a accident

vinny1275 - 20/12/06 at 12:42 PM

quote:

I've heard of people bumping it when taking the spare out - then wondering why the car won't start


Did this a few times in swmbo's dad's V6 Cossie powered sierra. After every track day, we'd lob the slicks in the boot, drive off, get about 100 yards, then (cough,splutter, die)....

20 seconds scratching heads, then ahhh yeh, I remember....

The even funnier thing is, that when I *did* crash the car (quarry at Castle Combe), it kept running. The body damage put paid to the rest of the day tho......

romer - 20/12/06 at 12:54 PM

One of our motor club members had an early injection car.
He had an accident one weekend (nothing to do with an event) and the car was totaly engulfed with fire. I believe it was before those switches were standard fitment and the pump was just feeding the fire . . . . . . . . . . we now have a named trophy in his memory.


My suggestion, if you can, fit it - it may not be for a tin top, but if you unconscious (sp?) . . . . dread the thought!

robertst - 20/12/06 at 05:26 PM

but obviously it doesnt work with a mechanical fuel pump? so it is rather pointless to haveit if you have a carb engine, unless you have changed the mech pump for an electric one...

the_fbi - 20/12/06 at 05:51 PM

quote:
Originally posted by robertst
but obviously it doesnt work with a mechanical fuel pump? so it is rather pointless to haveit if you have a carb engine, unless you have changed the mech pump for an electric one...

Or you have a BEC

snapper - 20/12/06 at 08:19 PM

Inertia switches will cut the power to anything in the event of a big stop, so you could wisely use it to cut the spark, or the whole electrical system.
No spark, no engine go round,no mechanical fuel pump.
I did think about about the oil presure switch as a cut off but in the event of a big off your ass may be on fire with the engine still having enough go to fuel your own personal barbeque