Can anyone tell me which wire on alternator, if disconnected, will kill the engine? Should this wire be disconnected or grounded? This is for a rear battery cutoff switch. I didnt find this specific info in the archives. Vehicle is in sig. Thanks

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Ford red 1991 Formula 350. ROH 16in wheels, 1998 Grey Leather, street/strip 700r4 2400 stall, EIBACH springs, Strut tower brace, Poly Bushings
3.73 SLP POSI, 26 spline Moser Axles, mid SLP cam, grear drive, SLP runners, 24# injectors, Taylor wires, Accel Coil, Accel Ignition, B&M Megashifter, K&N conical, AFPR, SLP 1 3/4 coated shorty headers, 3in cat, 3in. mandrel-bent single exhaust, flowmaster, TB air foil, 180 stat, SSM SFC's, SPOHN lower control arm adapters, custom burned prom, Hotchkis Lower control arms, Aluminum Driveshaft, ported upper and lower, q-logic kick panels.
Instant Messenger JMatlock88

 

The engine will run without the alternator(using power from the battery).


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350 with stealth intake, holley carb, 470 lift cam. 700r4 with .5 boost valve, vette servo, tci lock-up kit, B&M megashifter. Richmond 3.73 gears, powertrax locker, timkin bearings, synthetic lube. Custom 3 inch single into 2 2.5 pipes. 1 1/2 drop springs, 1 5/16 solid front sway bar, 1 inch rear bar, custom subframe connectors, custom LCA relocation brackets. Kobel ground FX, currant red metallic paint. Lots of other stuff...
82camaro

 

I just wanted to add a further explanation:

The positive wire from the battery will be disconnected via a high amperage switch at back of car. Per NHRA rules, the engine must die as well when this switch is tripped. Disconnecting pos battery cable alone will not kill engine. I will simply relay off of the switch to the mystery wire, either shorting it to ground or disconnecting it. Which wire is the mystery wire? Hope that explains better... Thanks!

 

Okay, here it is: (picture loading)



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Ford red 1991 Formula 350. ROH 16in wheels, 1998 Grey Leather, street/strip 700r4 2400 stall, EIBACH springs, Strut tower brace, Poly Bushings
3.73 SLP POSI, 26 spline Moser Axles, mid SLP cam, grear drive, SLP runners, 24# injectors, Taylor wires, Accel Coil, Accel Ignition, B&M Megashifter, K&N conical, AFPR, SLP 1 3/4 coated shorty headers, 3in cat, 3in. mandrel-bent single exhaust, flowmaster, TB air foil, 180 stat, SSM SFC's, SPOHN lower control arm adapters, custom burned prom, Hotchkis Lower control arms, Aluminum Driveshaft, ported upper and lower, q-logic kick panels.
Instant Messenger JMatlock88

 

alright, i know this is an EXTREMELY old thread, but i too am doing the same shutoff circuit and had the same question... picture is not loading from obvious reasons(2001)

Any input is appreciated!

 

In the end, I rewired my 12v supply to the ECU in front of the switch to kill the engine. That way when the switch is tripped in an emergency, the ECU cuts off the signal to the fuel pumps, injectors, etc.

Alternatively, I robbed this off the internet back in 2001ish...haven't tested it, but give it a try if you'd like.

 

AWESOME! thanks man! im going to have to sit down and look at that schematic and decide what route to take with the project, but that definitely helps... i like your idea a little better though!

i really need to come see you for a small donation



also, on a side note for the same project, i was wondering if it would be frowned upon to run a power wire bypassing the shutoff to my stereo, keeping my settings even when the switch is off. I also plan on using the switch to shut the rest of the vehicle off when it is not being driven..

would this violate track rules??

 

I know what you mean about the radio settings. Yes, it would be frowned upon to have a hot wire that bypasses the switch. Here's what I would do...

Make the separate bypass wire to your radio as you wish. In a very obvious location near the battery, use an in-line, two-piece fuse on the wire. When you go to the track, separate the fuse canister halves and remove the fuse. With it obvious that the bypass power wire is disconnected, the inspector will have no problem with the configuration.