EFI fuse kill switch
06-27-2020, 07:44 PM
#1
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EFI fuse kill switch
Is it fine to have a kill switch on the EFI fuse since it is always getting power? I've already kind of done this using 14 gauge wire and a switch out of a 4runner.
Last edited by STERFRY333; 06-30-2020 at 06:58 AM.
06-28-2020, 05:52 AM
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I would be very careful with that. The wire TO the EFI fuse is either protected by the 30amp AM2 fuse http://web.archive.org/web/201204170.../2powersou.pdf , or, according to my '94 EWD, only the fusible link. So if you have a short to ground anywhere along that stretch of wire to your cab (and before your inline fuse), the wire has to carry 30 amps (or fusible link amperage, if my EWD is correct) before the AM2 fuse blows. In run-of-the-mill house wiring, 14ga wire is okay for 15amps. (This is apples and oranges, but you get the idea.)
Replacing the EFI fuse with a switch is clever; it's easy to do and easy to reverse. But you could significantly reduce your risk by splicing a switch into B-Y wire from the IGN fuse to the EFI coil. That wire is already under the dash, so your wire run to the switch is much shorter (and as a result, much more discrete). If you're worried about being able to easily reverse it (say, you want to sell the truck and somehow a kill switch is not a positive), you could use opposite gender "bullet" connectors at the splice. To disable the switch, just unplug the connectors from the switch and plug them into each other.
If you want to get really fancy, you can put the switch in the FC circuit from the VAF to the COR (again, under the dash, but over on the passenger side). It is sometimes said that a clever thief will immediately suspect a "kill switch" when the truck cranks but won't fire. With the switch in the FC circuit, the truck will start right up but only run for a few seconds. A thief who really knows his Toyotas might then suspect such a kill circuit, but by then he's already attracted attention to the truck that keeps starting and stopping.
Replacing the EFI fuse with a switch is clever; it's easy to do and easy to reverse. But you could significantly reduce your risk by splicing a switch into B-Y wire from the IGN fuse to the EFI coil. That wire is already under the dash, so your wire run to the switch is much shorter (and as a result, much more discrete). If you're worried about being able to easily reverse it (say, you want to sell the truck and somehow a kill switch is not a positive), you could use opposite gender "bullet" connectors at the splice. To disable the switch, just unplug the connectors from the switch and plug them into each other.
If you want to get really fancy, you can put the switch in the FC circuit from the VAF to the COR (again, under the dash, but over on the passenger side). It is sometimes said that a clever thief will immediately suspect a "kill switch" when the truck cranks but won't fire. With the switch in the FC circuit, the truck will start right up but only run for a few seconds. A thief who really knows his Toyotas might then suspect such a kill circuit, but by then he's already attracted attention to the truck that keeps starting and stopping.
Last edited by scope103; 06-28-2020 at 05:59 AM.
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RAD4Runner (06-30-2020)
06-28-2020, 09:07 AM
#3
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I would be very careful with that. The wire TO the EFI fuse is either protected by the 30amp AM2 fuse http://web.archive.org/web/201204170.../2powersou.pdf , or, according to my '94 EWD, only the fusible link. So if you have a short to ground anywhere along that stretch of wire to your cab (and before your inline fuse), the wire has to carry 30 amps (or fusible link amperage, if my EWD is correct) before the AM2 fuse blows. In run-of-the-mill house wiring, 14ga wire is okay for 15amps. (This is apples and oranges, but you get the idea.)
Replacing the EFI fuse with a switch is clever; it's easy to do and easy to reverse. But you could significantly reduce your risk by splicing a switch into B-Y wire from the IGN fuse to the EFI coil. That wire is already under the dash, so your wire run to the switch is much shorter (and as a result, much more discrete). If you're worried about being able to easily reverse it (say, you want to sell the truck and somehow a kill switch is not a positive), you could use opposite gender "bullet" connectors at the splice. To disable the switch, just unplug the connectors from the switch and plug them into each other.
If you want to get really fancy, you can put the switch in the FC circuit from the VAF to the COR (again, under the dash, but over on the passenger side). It is sometimes said that a clever thief will immediately suspect a "kill switch" when the truck cranks but won't fire. With the switch in the FC circuit, the truck will start right up but only run for a few seconds. A thief who really knows his Toyotas might then suspect such a kill circuit, but by then he's already attracted attention to the truck that keeps starting and stopping.
Replacing the EFI fuse with a switch is clever; it's easy to do and easy to reverse. But you could significantly reduce your risk by splicing a switch into B-Y wire from the IGN fuse to the EFI coil. That wire is already under the dash, so your wire run to the switch is much shorter (and as a result, much more discrete). If you're worried about being able to easily reverse it (say, you want to sell the truck and somehow a kill switch is not a positive), you could use opposite gender "bullet" connectors at the splice. To disable the switch, just unplug the connectors from the switch and plug them into each other.
If you want to get really fancy, you can put the switch in the FC circuit from the VAF to the COR (again, under the dash, but over on the passenger side). It is sometimes said that a clever thief will immediately suspect a "kill switch" when the truck cranks but won't fire. With the switch in the FC circuit, the truck will start right up but only run for a few seconds. A thief who really knows his Toyotas might then suspect such a kill circuit, but by then he's already attracted attention to the truck that keeps starting and stopping.
06-30-2020, 06:25 AM
#4
Second Scope's comments.
It's also often safer, and requires thinner wires to put kill switches on low-current circuit like relay coil, instead of load, side.
AND I SUGGEST YOU TAKE DOWN PICTURE OF YOUR KILL SWITCH AND WHERE YOU PUT IT.
Thieves also do their research on forums
It's also often safer, and requires thinner wires to put kill switches on low-current circuit like relay coil, instead of load, side.
AND I SUGGEST YOU TAKE DOWN PICTURE OF YOUR KILL SWITCH AND WHERE YOU PUT IT.
Thieves also do their research on forums
06-30-2020, 06:43 AM
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Uh, not really.
It's a popular movie trope. Lots of young men in black turtle-necks, sitting in a darkened room with giant computer screens. After a few seconds, one shouts "I'm in!"
If you're a crack-head looking to quickly steal some transportation out of here, it's much easier to just walk down any street with a pair pliers and a rock. Trying to figure out where STERFRY333 even lives is a lot more work.
It's a popular movie trope. Lots of young men in black turtle-necks, sitting in a darkened room with giant computer screens. After a few seconds, one shouts "I'm in!"
If you're a crack-head looking to quickly steal some transportation out of here, it's much easier to just walk down any street with a pair pliers and a rock. Trying to figure out where STERFRY333 even lives is a lot more work.
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swampedout (07-03-2020)
06-30-2020, 06:57 AM
#6
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Thread Starter
Second Scope's comments.
It's also often safer, and requires thinner wires to put kill switches on low-current circuit like relay coil, instead of load, side.
AND I SUGGEST YOU TAKE DOWN PICTURE OF YOUR KILL SWITCH AND WHERE YOU PUT IT.
Thieves also do their research on forums
It's also often safer, and requires thinner wires to put kill switches on low-current circuit like relay coil, instead of load, side.
AND I SUGGEST YOU TAKE DOWN PICTURE OF YOUR KILL SWITCH AND WHERE YOU PUT IT.
Thieves also do their research on forums
07-03-2020, 12:40 PM
#7
Registered User
I ran my switch direct to the EFI fuse, it also resets the ECU whenever I trip it. Nice to clear a check engine light quickly but sometimes its gotta warm up for a bit after I trip it.
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07-03-2020, 03:49 PM
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07-03-2020, 04:59 PM
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In the the FC circuit, the truck will start, run for a few seconds, then quit. In the fuel pump circuit, it will crank but will not fire. Plus you're switching a much higher current; if your switch gets damaged by the current (not likely, but something to think about) you won't be able to start it.
07-03-2020, 05:06 PM
#11
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Ya' gotta make up yer mind.
In the the FC circuit, the truck will start, run for a few seconds, then quit. In the fuel pump circuit, it will crank but will not fire. Plus you're switching a much higher current; if your switch gets damaged by the current (not likely, but something to think about) you won't be able to start it.
In the the FC circuit, the truck will start, run for a few seconds, then quit. In the fuel pump circuit, it will crank but will not fire. Plus you're switching a much higher current; if your switch gets damaged by the current (not likely, but something to think about) you won't be able to start it.
07-03-2020, 05:13 PM
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The FC wire to the COR should be G-Y to pin 4, if that means anything to you. The VAF grounds it to close the COR.
At the COR, the Fuel pump wire is L (bLue) to pin 1. The COR connects the wire to battery to run the pump.
Got a multimeter? Don't try to do anything electrical without one.
At the COR, the Fuel pump wire is L (bLue) to pin 1. The COR connects the wire to battery to run the pump.
Got a multimeter? Don't try to do anything electrical without one.
07-04-2020, 01:34 PM
#13
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The FC wire to the COR should be G-Y to pin 4, if that means anything to you. The VAF grounds it to close the COR.
At the COR, the Fuel pump wire is L (bLue) to pin 1. The COR connects the wire to battery to run the pump.
Got a multimeter? Don't try to do anything electrical without one.
At the COR, the Fuel pump wire is L (bLue) to pin 1. The COR connects the wire to battery to run the pump.
Got a multimeter? Don't try to do anything electrical without one.
I think that's the one. The label on the plug says it's connected to pin 4. My Haynes Manuel says it's just G but so far it's gotten most of the wire colours wrong.
Last edited by STERFRY333; 07-04-2020 at 01:56 PM.
07-04-2020, 05:01 PM
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What does your multimeter tell you?
if I'm correct, with KOEO, you should get battery (~12v) on the G-Y wire. When your assistant pushes the vane in the VAF, G-Y should go to ground, the relay should close, and the fuel pump start. Then you know you have the correct wire.
No assistant? Well, you could just use a wire to connect G-Y to ground. If it's the correct wire, the pump will start. But what if it isn't? What if it is connected directly to battery (not through the relay coil)? Then shorting it to ground will blow a fuse. (If you short W-R to ground, you'll blow the EFI fuse.) So you could use a test-light to ground. (Why would that make a difference? Why would it work?)
if I'm correct, with KOEO, you should get battery (~12v) on the G-Y wire. When your assistant pushes the vane in the VAF, G-Y should go to ground, the relay should close, and the fuel pump start. Then you know you have the correct wire.
No assistant? Well, you could just use a wire to connect G-Y to ground. If it's the correct wire, the pump will start. But what if it isn't? What if it is connected directly to battery (not through the relay coil)? Then shorting it to ground will blow a fuse. (If you short W-R to ground, you'll blow the EFI fuse.) So you could use a test-light to ground. (Why would that make a difference? Why would it work?)
07-04-2020, 05:18 PM
#15
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Thread Starter
What does your multimeter tell you?
if I'm correct, with KOEO, you should get battery (~12v) on the G-Y wire. When your assistant pushes the vane in the VAF, G-Y should go to ground, the relay should close, and the fuel pump start. Then you know you have the correct wire.
No assistant? Well, you could just use a wire to connect G-Y to ground. If it's the correct wire, the pump will start. But what if it isn't? What if it is connected directly to battery (not through the relay coil)? Then shorting it to ground will blow a fuse. (If you short W-R to ground, you'll blow the EFI fuse.) So you could use a test-light to ground. (Why would that make a difference? Why would it work?)
if I'm correct, with KOEO, you should get battery (~12v) on the G-Y wire. When your assistant pushes the vane in the VAF, G-Y should go to ground, the relay should close, and the fuel pump start. Then you know you have the correct wire.
No assistant? Well, you could just use a wire to connect G-Y to ground. If it's the correct wire, the pump will start. But what if it isn't? What if it is connected directly to battery (not through the relay coil)? Then shorting it to ground will blow a fuse. (If you short W-R to ground, you'll blow the EFI fuse.) So you could use a test-light to ground. (Why would that make a difference? Why would it work?)
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RAD4Runner (07-05-2020)
11-03-2020, 10:40 PM
#16
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What does your multimeter tell you?
if I'm correct, with KOEO, you should get battery (~12v) on the G-Y wire. When your assistant pushes the vane in the VAF, G-Y should go to ground, the relay should close, and the fuel pump start. Then you know you have the correct wire.
No assistant? Well, you could just use a wire to connect G-Y to ground. If it's the correct wire, the pump will start. But what if it isn't? What if it is connected directly to battery (not through the relay coil)? Then shorting it to ground will blow a fuse. (If you short W-R to ground, you'll blow the EFI fuse.) So you could use a test-light to ground. (Why would that make a difference? Why would it work?)
if I'm correct, with KOEO, you should get battery (~12v) on the G-Y wire. When your assistant pushes the vane in the VAF, G-Y should go to ground, the relay should close, and the fuel pump start. Then you know you have the correct wire.
No assistant? Well, you could just use a wire to connect G-Y to ground. If it's the correct wire, the pump will start. But what if it isn't? What if it is connected directly to battery (not through the relay coil)? Then shorting it to ground will blow a fuse. (If you short W-R to ground, you'll blow the EFI fuse.) So you could use a test-light to ground. (Why would that make a difference? Why would it work?)
I recently installed this kill switch (interrupting the G-Y wire). It totally worked but when I went for a test drive, a few miles down the road, I was gearing down from 5th to 4th and the truck lost power and stalled. I saw that the EFI fuse blew, replaced it and was back on the road but stalled again on the way home (gearing down again, this time from 4th to 3rd). So I replaced the EFI fuse again but this time, upon starting, the fuse blew again and I was stuck on the road. Luckily a Jeep guy saved me and towed me the rest of the way home; pls don't tell the moderators as I will probably be kicked off Yotatech in shame).
I've searched the forums and learned about the O2 wires getting burnt and shorting and did the test outlined by RAD4Runner here. No luck, so my theory is it had to be my shoddy kill switch install + the sudden jerk of downshifting?. My question is if a piece of exposed G-Y wire touch the W-R, would that be blowing the fuse? I've since re-wired the kill switch and so far I haven't been able to blow the fuse.
11-03-2020, 10:49 PM
#17
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Mr. Scope:
I recently installed this kill switch (interrupting the G-Y wire). It totally worked but when I went for a test drive, a few miles down the road, I was gearing down from 5th to 4th and the truck lost power and stalled. I saw that the EFI fuse blew, replaced it and was back on the road but stalled again on the way home (gearing down again, this time from 4th to 3rd). So I replaced the EFI fuse again but this time, upon starting, the fuse blew again and I was stuck on the road. Luckily a Jeep guy saved me and towed me the rest of the way home; pls don't tell the moderators as I will probably be kicked off Yotatech in shame).
I've searched the forums and learned about the O2 wires getting burnt and shorting and did the test outlined by RAD4Runner here. No luck, so my theory is it had to be my shoddy kill switch install + the sudden jerk of downshifting?. My question is if a piece of exposed G-Y wire touch the W-R, would that be blowing the fuse? I've since re-wired the kill switch and so far I haven't been able to blow the fuse.
I recently installed this kill switch (interrupting the G-Y wire). It totally worked but when I went for a test drive, a few miles down the road, I was gearing down from 5th to 4th and the truck lost power and stalled. I saw that the EFI fuse blew, replaced it and was back on the road but stalled again on the way home (gearing down again, this time from 4th to 3rd). So I replaced the EFI fuse again but this time, upon starting, the fuse blew again and I was stuck on the road. Luckily a Jeep guy saved me and towed me the rest of the way home; pls don't tell the moderators as I will probably be kicked off Yotatech in shame).
I've searched the forums and learned about the O2 wires getting burnt and shorting and did the test outlined by RAD4Runner here. No luck, so my theory is it had to be my shoddy kill switch install + the sudden jerk of downshifting?. My question is if a piece of exposed G-Y wire touch the W-R, would that be blowing the fuse? I've since re-wired the kill switch and so far I haven't been able to blow the fuse.
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