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RobertSmalls · 07-09-2010, 12:03 AM

It's come to my attention that I never wrote about my kill switch. Here's a how-to.

Having a manual kill switch moved me from around 45mpg on very short trips to around 60mpg. It's a boon around town, though not as useful on the highway. It eliminates engine-on time sitting at red lights when the cabin heater is on, or when the car's not fully warmed up, or when you've got a good neutral coast going.

Installing a kill switch on the Insight is harder than on most cars, but I still recommend it. You need to kill all three fuel injectors, and then you need the clutch switch held closed so the engine doesn't auto-restart. You could take care of the clutch switch with a circuit board, or use your left leg until you're below 20mph, but I'm using an assist/regen disable switch (see also here).

Killing the fuel injectors is easy: pass each of the injector signals through a relay. The relay I used opens three different circuits simultaneously when you turn it on. I cut in to the injector wires at the ECU, which is located in the passenger footwell below the carpet. On one side of my cut, I attached a spade connector. On the other side, I soldered on a 6" length of wire with a spade connector on the end. Then plug the injector wires in to the relay.

IGP1 and IGP2 have +12V, INJ1-3 are the injectors, and if you want a ground, I think that's what PG1 and PG2 are.

One leg of the relay's coil is attached to a +12V rail at the ECU, and the other leg goes to a momentary switch zip-tied to the gear knob. The other leg of said momentary switch goes to ground. Press the button, and it powers up the relay and kills the engine.

You can hit the switch to kill the engine at any time. The engine will go in to auto-stop and stay there until you put it into gear, open the clutch switch, or tap the throttle. This makes EOC a breeze in the Insight. Plus, you retain power steering, airbags, mpg instruments, and everything else while coasting.

Limitations: unless you build the proper FAS circuitboard or a DC/DC converter toggle switch, your charging system shuts down during an engine kill. Also, due to the interaction of my brake lights and my IMA disable switch, if you lift off of the brakes above 20mph, the engine re-starts and has to be killed again if desired.

07-09-2010, 12:03 AM	#162 (permalink)
RobertSmalls Left Lane Ecodriver Join Date: Aug 2008 Location: Buffalo, NY, USA Posts: 2,257 Prius C - '12 Toyota Prius C Thanks: 79 Thanked 287 Times in 200 Posts	It's come to my attention that I never wrote about my kill switch. Here's a how-to. Having a manual kill switch moved me from around 45mpg on very short trips to around 60mpg. It's a boon around town, though not as useful on the highway. It eliminates engine-on time sitting at red lights when the cabin heater is on, or when the car's not fully warmed up, or when you've got a good neutral coast going. Installing a kill switch on the Insight is harder than on most cars, but I still recommend it. You need to kill all three fuel injectors, and then you need the clutch switch held closed so the engine doesn't auto-restart. You could take care of the clutch switch with a circuit board, or use your left leg until you're below 20mph, but I'm using an assist/regen disable switch (see also here). Killing the fuel injectors is easy: pass each of the injector signals through a relay. The relay I used opens three different circuits simultaneously when you turn it on. I cut in to the injector wires at the ECU, which is located in the passenger footwell below the carpet. On one side of my cut, I attached a spade connector. On the other side, I soldered on a 6" length of wire with a spade connector on the end. Then plug the injector wires in to the relay. IGP1 and IGP2 have +12V, INJ1-3 are the injectors, and if you want a ground, I think that's what PG1 and PG2 are. One leg of the relay's coil is attached to a +12V rail at the ECU, and the other leg goes to a momentary switch zip-tied to the gear knob. The other leg of said momentary switch goes to ground. Press the button, and it powers up the relay and kills the engine. You can hit the switch to kill the engine at any time. The engine will go in to auto-stop and stay there until you put it into gear, open the clutch switch, or tap the throttle. This makes EOC a breeze in the Insight. Plus, you retain power steering, airbags, mpg instruments, and everything else while coasting. Limitations: unless you build the proper FAS circuitboard or a DC/DC converter toggle switch, your charging system shuts down during an engine kill. Also, due to the interaction of my brake lights and my IMA disable switch, if you lift off of the brakes above 20mph, the engine re-starts and has to be killed again if desired. Attached Thumbnails Last edited by RobertSmalls; 07-09-2010 at 12:08 AM..