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Old 12-01-2008, 12:56 PM   #9 (permalink)
Moderate your Moderation.
Join Date: Nov 2008
Location: Troy, Pa.
Posts: 8,919

Pasta - '96 Volkswagen Passat TDi
90 day: 45.22 mpg (US)
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Whatever happens, I prefer to also cut the power to the coil/ignition system. I've been told that since the coil/ignitor setup is essentially a capacitor, that it shouldn't be left with power when it's not discharging.

I don't know if it's true or not, I never bothered to research it, because it happens to fit into my cutoff switch plan anyway, but every time I've made a cutoff switch for anything, that has been the primary thought.

Other than that, I don't like cutting fuel first, as this can put you in a lean situation (especially a fuel-cut rev limiter).

And if you cut ignition first, without cutting the fuel pump, you're still pumping fuel through the engine until it stops... so you're flooding the engine, putting fuel into your oil, and polluting that much more... which is why I decided to make a fuel/ignition cutoff instead of one or the other...

I'm thinking it would be easier to cut my injectors though, since they share a common signal with a switched (at the ECU) ground.

I could put the switch on the signal... but as soon as I hit it, I'd end up with a code 16 in my ECU (Injector(s)) That wouldn't reset unless I put a ECU reset switch in my car... (My car's reset procedure is "pull the hazard fuse" but you can just switch it so that it grounds momentarily)
"ʞɐǝɹɟ ɐ ǝɹ,noʎ uǝɥʍ 'ʇı ʇ,usı 'ʎlǝuol s,ʇı"

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