Fuel Pump Inertia Switch

[Guest piddy]

Hi.

when fitting the injection engine what FUEL PUMP INERTIA SWITCH have you used?

The sierra one or after market?

Thanks.

[Jon Bradbury]

Hi Piddy

 

I've got a carb jobbie with the Sierra switch. So long as yours works I can't see why you'd want to pay good money for an aftermarket one. It's not like it's visible (well, mine's in the boot but covered with a flap of carpet) or particularly large.

 

Cheers

 

JonB

 

 

+++ WARNING +++ WARNING +++WARNING +++

This post is based on opinion, not experience as I don't have injection. But I think the inertia switches are the same for the DOHC engine variants.

[Guest bloke]

are they required? (for inj)

[Big Jim]

are they required?

Mmmmmm..................Not really............but.......................

 

They are for fitting into the electric fuel pump electrical feed, so that should you have a bump, the inertia switch will operate and cut off the electrical current to the fuel pump, thus stopping fuel still pumping out to fuel any potential fire.

 

I am "thinking" of putting one in my car, Mitch has given me a Sierra one, which is basically a ball bearing that gets unseated in the event of a bump. I'm a little reluctant to fit this, as with the harder suspension of a Hood, it could easily get unseated with hitting a pot-hole or such, so I wouldn't want it in the boot where I couldn't reset it quickly.

Alternatively, you can get a switch that goes into an oil gallery hole on the engine, this makes contact, (thus allowing the electric pump to work) only once the oil pressure has reached a certain pressure (I think it's around 5lb?) this means you've got to crank the engine over some to get the oil pressure up, before any fuel is pumped to the carbs / injection system.

So I'm still "thinking"

[Guest piddy]

Jim.

There are a couple of westfield ones on E bay at the moment.

they may take the hard suspension better than the Ford item.

[Guest chris brown]

I have the ford one in the side of the boot and never had any problem with it apart from when some kind sole ran into the car when it was parked at Donington last year. :gdit: :gdit: It’s about the last thing you think of when your car won’t start when you know it was fine when you left it You also get allot of stick from certain members.

[Guest Battery Bill]

Piddy

Standard one in ours, No problems ours is also in the Boot beside the whatsit

[Guest Battery Bill]

Chris

You also get allot of stick from certain members. 

 

I can't imagine you getting any stick

[nicko]

Hi all, I've got the injection engine and fitted my inertia switch adjacent to the fuel pump relay, where all the other electrickery bits are. Don't know if it works yet though, need a new battery to try to fire it up!!!

 

Nicko

[Jon Bradbury]

I'm a little reluctant to fit this, as with the harder suspension of a Hood, it could easily get unseated with hitting a pot-hole or such, so I wouldn't want it in the boot where I couldn't reset it quickly.

Jim

 

I've got mine in the boot tucked in the right hand corner above the fuel sender and pump. Resetting it is a doddle, even with the flap of carpet covering it. I'd recommend you fit it - you could always remove it if it didn't work out. Or, just screw it down where you intend to fit it, drive round some bumpy roads for a while and see if it needs resetting when you get home. You'll then know if it's going to be a problem with your hard suspension or not, without going to the bother of splicing it into the loom.

 

It takes quite a whack to unseat the ball. I suspect it is designed to unseat on lateral shocks rather than longitudinal (I mean up-down as per normal suspension travel). I've had no problems with mine and regularly go over speed bumps at a decent speed. Even with the Zeemerides it's quite a bounce.

 

Alternatively, you can get a switch that goes into an oil gallery hole on the engine, this makes contact, (thus allowing the electric pump to work) only once the oil pressure has reached a certain pressure (I think it's around 5lb?) this means you've got to crank the engine over some to get the oil pressure up, before any fuel is pumped to the carbs / injection system.

 

I'm not sure what your ignition system is like, but the ECU on my carb DOHC engine only turns the pump on when the engine is turning. There's a sensor on the crank. I'd guess there's no electrickery in your engine bay so the oil switch would be a good idea.

 

So I'm still "thinking"

 

Go on, do it, you know you want to...