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inertia switch??!!
chris_smith - 27/9/05 at 08:46 AM

is it an sva requirement for an inertia switch to be fitted on fuel pump???

cheers in advance chris


rayward - 27/9/05 at 08:52 AM

if your using a high pressure(injection fuel system) Yes.

a bloke on ebay was selling them for £7.99

Ray

[Edited on 27/9/05 by rayward]


Mix - 27/9/05 at 09:13 AM

Ray

Where do you get that info from? I can't find a reference to it

Mick


MikeR - 27/9/05 at 09:37 AM

not sure if its a requirement but as i've said before my mate who does FI systems in production cars swears we're all going to die in a firey inferno.

Since talking to him, i'm thinking of fitting one - just got to figure out how to do it / where to get one from.


rayward - 27/9/05 at 09:47 AM

will try and find the relevant bits of info from the manual.

here's the link for ebay switches £7.99 inc P+P NTDWM

cLiCk HeRe


Ray


chris_smith - 27/9/05 at 10:00 AM

yeah thats the one i was lookin at


DarrenW - 27/9/05 at 10:18 AM

Ref it being an SVA requirement - i dont think it is referenced directly in the manual but seeing as OEM's use them the tester may well cite it as a good thing to have and therefore make it a fail point. Im sur ethey wont have to try hard and find an arguable statement in the book. For a few quid its probs a good idea.

If you are using a mech pump am i right in assuming there isnt anything similar that can be used? (ie are inertia switches only electrical?)


rayward - 27/9/05 at 10:28 AM

main reason for the inertia switch is usually an electric pump sits in the tank and pumps fuel from te tank to the engine, and in injection systems, back to the tank again, if the car is crashed, there is a chance a fuel laine will be severed, and if the pump keeps pumping will spray fuel everywhere.

the mechanical fuel pumps are fitted to the engine and draw fuel from the tank, so the need to shut them off is less.


NS Dev - 27/9/05 at 12:35 PM

It is not a requirement that I have ever seen.

If the injection line is fractured, the engine stops instantly (almost), and if it stops, any half decent injection system (incl most if not all road car systems) will cut the power to the fuel pump (in the absence of pulses from the crank position sensor)

My MBE systems never use an inertia switch.


JAG - 7/10/05 at 01:05 PM

I've got this inertia switch (the one in the Ebay link) on my injected Mazda MX5 engine.

I got it from under the centre console of a Rover 214 in my local scrapyard - he charged me £5 for it. It's now mounted on the engine side of my bulkhead near the relays and fuses.

If you're sitting in the drivers seat of a Rover 214/216/414/416 the switch is located behind the centre console, just behind the radio/stereo etc... under the trim panels.


MikeR - 7/10/05 at 05:38 PM

oh well, i bought one from ebay - got it now so no worries.


NS Dev - 11/10/05 at 03:26 PM

quote:
Originally posted by rayward
main reason for the inertia switch is usually an electric pump sits in the tank and pumps fuel from te tank to the engine, and in injection systems, back to the tank again, if the car is crashed, there is a chance a fuel laine will be severed, and if the pump keeps pumping will spray fuel everywhere.

the mechanical fuel pumps are fitted to the engine and draw fuel from the tank, so the need to shut them off is less.


just going back to this one, on an injection car the fuel delivery should stop just as surely as it will on a car with a mech pump. If the fuel line fractures, the engine stops, the tachometric fuel pump relay or the ECU detects the lack of pulses and stops the pump.