Which type of switch

What kind of switch do you use if you wanted a fuel kill switch? I went to Radio Shack and they had switches that are rated @ 6A, 3A, 25A etc. Which would be best for a fuel kill switch?

Look at the fuel pump fuse, you need a switch that can handle that amount of amps. If they don't have that number, get a switch rated for more than the fuse that controls the pump.

why would you want a fuel kill switch?

so if someone tries to steal ur car they cant cause no fuel gets to the injection system..

if i were you bro i go with something not less than 25amps at 12v dc. they have automotive switches that are rated at 25 and 30 amps.

id put it somewhere where they cant see the lines at all.

im hopefully doing this this week. i havent had the time cause i converted my bumper lights and been working on a custom intake system and school.

if u can man report back, or hit me up on aim...."pino401" id like to talk to you about it.

o and dont get a lighted swithc...ur trying to hide it for a reason hahaha

but if its just a switch-wouldn't they be able to just flip it "on"
and wouldn't it be a hassle to flip it "off" everytime you leave your car?
why not just get an alarm?

that's why you hide it dude

that's why you hide it dude

Hey guys, no matter what the switch ratings are, you need to use a heavy duty relay. That way everything is totally isolated. You can wire it normally closed so if their is a problem, it should start.

If using a relay, you can do one thing even better. You can use an existing switch in the car like the rear defrost, power window, or just about any other button in the car. Then, you can install a real cheap switch to nothing for the thief to mess with. The thief will have absolutely no idea what to do. :evillol:

Hey guys, no matter what the switch ratings are, you need to use a heavy duty relay. That way everything is totally isolated. You can wire it normally closed so if their is a problem, it should start.

If using a relay, you can do one thing even better. You can use an existing switch in the car like the rear defrost, power window, or just about any other button in the car. Then, you can install a real cheap switch to nothing for the thief to mess with. The thief will have absolutely no idea what to do. :evillol:

i gots a question. since its a simple off and on switch and its not drawing alot of power as you would switch a lighting system why would u need to use a relay? are you saying just to incoorporate it into another swithc?

i wired my bumper lenses to a relay...much safer and less power drain but the fuel pump is just an on and off switch...care to explain?

i gots a question. since its a simple off and on switch and its not drawing alot of power as you would switch a lighting system why would u need to use a relay? are you saying just to incoorporate it into another swithc?

i wired my bumper lenses to a relay...much safer and less power drain but the fuel pump is just an on and off switch...care to explain?

Well, it is part of MECP training that you should always use a relay to switch anything and not the switch itself.

I have one on my car, i used a 20 amp 12 volt switch for mine and it works fine. I didnt use any relay's or anything i just cut the fuel pump wire, extended it and ran it to the switch

i under stand the fact that using a relay would help in the loss of current from the extended wire and the connection to the switch but we are talking about very little loss....lets do some calcualations to see if a relay is actually a benifit.

you obviously know some stuff about electronics so lets test some theroys.

would a switched system be less efficient than a relay system? would there be a huge benifit?

yet you do have a point, but is it worth doing it?? im not dissing you or anything im actually interested.

thanks!

Hello why are you doing a fuel cutoff anyway? Whenever the car is shutoff there is still gas in the lines it will start. If you do not want your standard starter kill up under the dash. Have a relay under the hood at the ignition or start circuit in your underhood.

If you want to be real slick.
Make it so your car has a "starter" button. Use either an existing button that you do not use or one that is camoflagued.
Disconnect this button also disconnect start wire at the ignition cylinder.
The back of the button should have two prongs/terminals on it if it has multiple prngs/term test to see which change when button is pushed in. In my acura i used my air recirculation button. If the button you use locks on with one push and locks off with another. You will have to trim a small tab. Which will make the switch only be active when it is pushed in. Otherwise the starter may get overcrank by the button locking up.
Now that you have your push button connect one side to a 12v source (memory) any circuit that is constantly hot. On the other term/prng run the lead to the underhood to the main fuse box. Where there are empty spots for relays and wire it To 85 wire 86 to ground take 87 to a heavy 12v source ahem: the battery with decent gauge wire like 10awg. 87a to nothing with 30 going to the start fuse/circuit.

IF the numbers confuse you just look at the relay it's usually printed on it. When connecting to the terminals on the relay use standard female spade connectors.
After you complete this daunting task it should break down like this. You put the key in the ignition turn it to the on or run position. You press your "starter" button which acts like a momentary switch when you hold it in 12v passes through it and out to the relay which switches from ground to 12v. Making the Starter fuse/circuit hot making the starter crank. When the engine starts let go of the button 12v no longer passes through the switch making the relay flip back to rest @ ground.

Ps Poncho i am dissapointed you didn't set these lads straight...

If this is too hazey please feel free to send me a private message i can break it down or fax you a diagram or check out www.bcae1.com/

i under stand the fact that using a relay would help in the loss of current from the extended wire and the connection to the switch but we are talking about very little loss....lets do some calcualations to see if a relay is actually a benifit.

you obviously know some stuff about electronics so lets test some theroys.

would a switched system be less efficient than a relay system? would there be a huge benifit?

yet you do have a point, but is it worth doing it?? im not dissing you or anything im actually interested.

thanks!

Well, in simple terms it is more about longevity. A basic flip switch usually will fail if under load when being used where a relay will not. I can't tell you how many switches I see go bad because of that. Plus, using a relay enables you to do so much more of a neat install or using the "ghost switch" technique already mentioned. Call me a creature of habit, I just always use a relay.

relays are the normally the part of choice because the low voltage requires a much higher current for a given power.

I'm with ponchnutty on this one... Use a relay.. I was reading down this post and was going to reply with use a relay until I read poncho's post.. but yeah, using a relay is very easy, and you can run any 12v wire from the battery to the switch, to the relay, and another from the relay to a ground on the car, then have a short extension from the pump to the relay, and hook into the other end of the pump supply line.. It's an easy setup, and makes it so easy to fix if the relay ever fails (which it should'nt if you get the right rating, manual should list what fuse your pump takes and get the same or higher).

thats true, very true....i think im going to consider using a relay now. those are easy to set up. i am going to try and find another source for the fuel pump cause i dont want to go all the way to the rear.

now oen quesiton, the 12v wire from a source to power the relay..shouldnt that be fused? now u have a fused fuel pump incase something goes wrong right?

im not sure how many amps is that fuel pump, i think u measure the resistance

30amp auto relay is good...

ill work with this tomorrow hopefully..

alright well, I would fuse it since it is going to your fuel pump... but since the relay is after the standard fuse to the fuel pump there shoudl'nt be a problem with just running the switch direct without a fuse... because the relay does'nt supply the power to the pump.. it's just a switch in the line.. they are totally independant circuits. the only interaction between the two is that one turns the other on/off. but if you want to be safe run it rhough your fusebox with a 12volt fuse just to be safe.. I would'nt bother getting a 10 amp fuse cuz if there's a surge and that wire grounds out the wire is just gonna *fzzzkk* and fry. you can run it direct from the fusebox and not even bother with a lead to the battery.. there should be a free slot on your internal or engine bay fuse boxes for some accessory you don't have....

i got another idea instead of splicing the fuel pump. there is a ecu fuse in the fuse box inside the car. if u tap that line and re-run it to a switch, it powers up the fuel pump and the main relay

ill work on this more tonight...it works i tried it and the voltage drop is only .8 volts.

and it wont reset the ecu...i tested it.

o and the line going back to the fuse box, i put the fuse inline so its perfect =)

hey whatever works. Just saying a fuse in the fusebox is cleaner looking, and easier to check...

cool let me ask u this. how do u use the extra slots in the engine bay or inside the car. id figure u would have to split it open so that u can run the lines right?

i would really like to run it like that cause of course it is really clean.

thanks