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Electric fuel pump safety cut out switch.
https://www.ausmini.com/forums/viewtopic.php?f=2&t=21950		 Page 1 of 2
Author:  Matt68 [ Mon Aug 28, 2006 5:07 pm ]
Post subject:  Electric fuel pump safety cut out switch.
I have an electric fuel pump. I have a switch to turn it on and off in a concealed location.

What I want is some way of turing it off in the event of an accident. fuel pumping into a hot engine bay after a crash doesn't seem like a happy ending to me. I have heard of impact switches, but they don't fill me with confidence.

What else can be used?

oil pressure switch? What if engine keeps running? Any other ideas?

What has everybody else with an electric pump got?

Matt
Author:  feralsprint [ Mon Aug 28, 2006 5:32 pm ]
Post subject: 
Matt

you will find that all modern fuel injected cars have inertia cut out switches to cut the fuel off in case of accident, you have to fit them at a certain angle to make them work and the best way to determine is to have a look at the car it comes off to determine tha angle they are set at, they work by cutting the power to the fuel pump

Jon
Author:  Mokesta [ Mon Aug 28, 2006 5:34 pm ]
Post subject: 
Buy a Rover cut out switch from Brickworx. They have a nice reset button feature but can activate on a pot hole or speed bump as per an old thread somehwhere here.
Author:  Matt68 [ Mon Aug 28, 2006 5:37 pm ]
Post subject: 
feralsprint wrote:
Matt

you will find that all modern fuel injected cars have inertia cut out switches to cut the fuel off in case of accident, you have to fit them at a certain angle to make them work and the best way to determine is to have a look at the car it comes off to determine tha angle they are set at, they work by cutting the power to the fuel pump

Jon


Thanks Jon, any pointers for which are a better one to look for?

Matt
Author:  Matt68 [ Mon Aug 28, 2006 5:39 pm ]
Post subject: 
Mokesta wrote:
Buy a Rover cut out switch from Brickworx. They have a nice reset button feature but can activate on a pot hole or speed bump as per an old thread somehwhere here.


Cheers,

Are there ones that don't trigger so easily?
I definately like the resettable feature, but don't enjoy the thought of having to reset it all the time!

Has anyone got one fitted?

Matt
Author:  Hanra [ Mon Aug 28, 2006 5:49 pm ]
Post subject: 
In the Emergency Locating Transmitters (ELT) for Helicopters that I work on, they have wats known as a 5-way axis G-Switch and a single axis G-switch. They require 12g's of force to allow the switch to close. These ELT's provide activation for 6 directions.

Basically all the G-switch is, is a cylinder closed off at each end, inside there is a spring attached to 1 end and a ball on the other end of the spring. Once 12g's are applied to it the spring extends all the way down the cylinder causing the ball to contact the socket at the other end of the cylinder. This then completes the circut and allows the ELT to transmit. After the force is applied the spring returns to its origainl position and is now reset for its next aircraft crash.

The 5-way axis G-Switches would be best used in a car. Unsure if anything like this is commercially available. But being for the Aviation Industry, they aint cheap..........
Author:  sports850 [ Mon Aug 28, 2006 5:56 pm ]
Post subject: 
I've been reading this and wondering as well , if you were to get one of the resettable ones someone mentioned from brickworks , would it be possible to wire it in so that when it was tripped by whatever savage bump in exactly the right direction , the fuel pump power was cut but a light came on on the dash to warn you so you could press the reset before the float bowl ran out of fuel ?
Author:  VicMini13 [ Tue Aug 29, 2006 8:20 am ]
Post subject: 
sports850 wrote:
I've been reading this and wondering as well , if you were to get one of the resettable ones someone mentioned from brickworks , would it be possible to wire it in so that when it was tripped by whatever savage bump in exactly the right direction , the fuel pump power was cut but a light came on on the dash to warn you so you could press the reset before the float bowl ran out of fuel ?


Connect the inertia switch to a double throw relay that has it's power sourced from a (ignition) switched live, then use the "NO" (Normally Open) to power the pump and the "NC" (Normally Closed) to power the idiot light.
Author:  sports850 [ Tue Aug 29, 2006 8:36 am ]
Post subject: 
Thought some form of a relay might do it but wasn't sure , thank's for that .
Author:  marcello [ Tue Aug 29, 2006 11:57 am ]
Post subject:  switch
when i first got my moke on the road my mechanic told me to fit this little switch that he gave me. it cuts out the fuel pump about 2 seconds after the engine fails to produce a spark at the coil. even if the igniton is left on. so if you stall, it cuts out. i have never had a problem with it. if you turn onnthe ignition but dont start the car, it just builds up a little pressure in the line and then stops until the engine is firing.
Author:  Matt68 [ Tue Aug 29, 2006 12:24 pm ]
Post subject: 
Sounds good, but what about if you are in a crash but the motor keeps running?

Is that likely?

Probably not i suppose. OK, what do i need to wire in a switch to work off the coil?


matt
Author:  Gilly [ Tue Aug 29, 2006 12:35 pm ]
Post subject: 
How about just switching off the ignition key :?
Author:  sports850 [ Tue Aug 29, 2006 12:43 pm ]
Post subject: 
Gilly wrote:
How about just switching off the ignition key :?


I'm guessing you haven't had a big crash Gilly , takes 15-20 seconds at least for you to start thinking straight . I had a head on with a combined speed of 160 k's in a corolla against an econovan . First 10 seconds or so was "well , that didn't hurt , f***ed the van , didn't hurt though , why's my bonnet up like that , that didn't hurt " and so on followed by "f*** , I'm blocking the road on a blind corner " , soon after by "sniff sniff , fuel , better turn the key off" ..... The fuel pump had stopped anyway and the engine had too because it was somewhat bent but it still took a while to register that I should turn off the ignition , and that was with a few bruises and what felt like a hang-over the following morning . I could imagine with more serious injuries there's the potential for a lot of fuel to be sprayed into the engine bay before you realised .

But I'll never forget the first thing through my mind , well , that didn't hurt ....
Author:  Lillee [ Tue Aug 29, 2006 1:38 pm ]
Post subject: 
Does anyone have part numbers for the cut off switch with reset button?
Author:  DRB33N [ Tue Aug 29, 2006 1:48 pm ]
Post subject: 
My auto electrician connected my fuel pump to the alternator so in the event of a head on colision the alternator stops inturn stops the fuel pump pumping.
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