Kill switch how-to

[epurvee]

I do have my sg2 set to hybrid. When auto stopping I believe the 97 geo's obd2 port stops sending data as the gauges do not update and then the sg2 turns off.

[epurvee]

I just wanted to confirm if this was the fuel injector harness you were talking about?

[VegasDude]

I've wanted a way to kill the engine without turning the key for awhile now. The problem with using the key is three-fold. Firstly it kills the power to all accessories. Second, the gauges all go out. This makes it harder to tell when the engine has fully stopped. At freeway speeds I've turned the key off and back on too soon at which point the engine came back to life. Thirdly the turn signals stop.

I installed a switch in series with the fuel injector circuit. This essentially replaces the fuel injector fuse with a loop of wire that runs to a switch in front of the shifter. The loop is also fuse protected, so if it gets grounded for whatever reason it will not start a fire.

I discovered that when the fuse is removed, the parking lights turn on whenever the car is on. I suppose this is to help a mechanic determine the problem if the car turns over but doesn't start. Unfortunately for me, this diagnostic feature disables the turn signals as well.

I used a single throw single pole 10A switch. This works perfectly: when the switch is pulled forward, the engines stops exactly as it would if the key was turned. But this time the gauges function. A bonus feature of the switch is DFCO at revs below 1500. The switch is not a momentary push button variety, I also chose to make forward the normal position. If for some reason it gets bumped, it would most likely be bumped into the on position.

[epurvee]

mwebb,

That worked perfectly once I figured out where everything was. I think I might make a how-to for a kill switch for 95-2001 Metro's.

[IsaacCarlson]

how much power do injectors use anyway? Can't you just put a switch on the main injector ground/power wire?

[epurvee]

The main fuse for the fuel injectors is 15A, however in the 95+ metros, breaking directly on this line will cause a full electronic reset in the car's computer. If you had a scangauge, it would cease to update during the reboot as the ODB2 port doesn't transmit data at this time.

[IsaacCarlson]

the reason I ask is because I have a 91 f-250.

[moorecomp]

Originally Posted by IsaacCarlson

how much power do injectors use anyway? Can't you just put a switch on the main injector ground/power wire?

On my car, the injector has a resistance of 14 ohms. If you do the math, that means it draws about 1 amp. Each injector firing at different times means the draw is not very much. I put a simple microswith on mine and have had no issues with it.

[Piwoslaw]

Originally Posted by moorecomp

On my car, the injector has a resistance of 14 ohms. If you do the math, that means it draws about 1 amp. Each injector firing at different times means the draw is not very much. I put a simple microswith on mine and have had no issues with it.

1A @ 12/14V, right? In my car the injector voltage is around 60V. I'm guessing that any new direct injection engine will have similar voltage.

[IsaacCarlson]

Even if the voltage IS 60V, it would not be drawing much. Most switches are rated for at least 15 AMPS. I would not be worried about it. I have been thinking about shutting off 3 cylinders for cruising, this would allow me to have HALF the draw on each switch. any thoughts?