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Ignition switch

Posted: 05 Jan 2021 21:32
by funwithmonkeys
I am trying to change the way I have things wired up to make it a bit cleaner in the car. Right now I have my ecu wired to a switch to power it. I would prefer to have it wired through the ignition switch but when you start the car it breaks the power connection to the acc power wires. Is there a way around this? I thought about just adding a simple push button to start with so the key can stay in the on position. I took a good look at it tonight and my wiring to the ignition switch does not match what the wiring diagram shows. Any help or ideas would be appreciated.

Re: Ignition switch

Posted: 06 Jan 2021 00:13
by Heinrich
had a similar issue on a nissan langley once, i think i used a diode from start position to the acc position to solve that problem.
i would suggest a diode driving a relay with a small value capacitor over the relay to keep it on for half a second or so to eliminate a on-off-on spike to the ecu

Re: Ignition switch

Posted: 06 Jan 2021 06:38
by icehouse
Hook your ECU switched power to the black with white stripe wire on the ignition. The wire that powers the coil. It gets power while cranking and with key on. Relay it if it takes a bit of juice. Don't want to burn down the ignition switch.

Re: Ignition switch

Posted: 06 Jan 2021 07:22
by funwithmonkeys
icehouse wrote:
06 Jan 2021 06:38
Hook your ECU switched power to the black with white stripe wire on the ignition. The wire that powers the coil. It gets power while cranking and with key on. Relay it if it takes a bit of juice. Don't want to burn down the ignition switch.
That's what I was looking for. Thanks Icehouse.

Re: Ignition switch

Posted: 07 Jan 2021 15:20
by 510rob
Norm, be careful with this. Some of the old key switches lose power between start and run; if the power drops out when you move from run to start then back to run, the ECU thinks it has been turned on three times and it dumps three quants of priming fuel via the injectors and causes all sorts of head-scratching, not to mention the ECU seems fine, then you crank and it takes a few seconds for the engine to light, then it stalls when you drop the key back to run - a nightmare for troubleshooting.

A 280ZX switch will mount in place of a 510 switch and should not have any interruption to the black/white power wire as you move between start position and run position.

Re: Ignition switch

Posted: 07 Jan 2021 15:24
by funwithmonkeys
Thanks Rob,
I did some toying with it last night and I got it working properly. I will post in my build thread what exactly I did when I am done with it. Changing one thing around escalated rather quickly and now I am doing a bunch of things.

Re: Ignition switch

Posted: 08 Jan 2021 07:24
by icehouse
510rob wrote:
07 Jan 2021 15:20
Norm, be careful with this. Some of the old key switches lose power between start and run; if the power drops out when you move from run to start then back to run, the ECU thinks it has been turned on three times and it dumps three quants of priming fuel via the injectors and causes all sorts of head-scratching, not to mention the ECU seems fine, then you crank and it takes a few seconds for the engine to light, then it stalls when you drop the key back to run - a nightmare for troubleshooting.

A 280ZX switch will mount in place of a 510 switch and should not have any interruption to the black/white power wire as you move between start position and run position.
If that happens connect the black with white stripe wire to the blue with black stripe. That is what has worked for me in the past. It seems the blue with black stripe was meant to bypass the ballast resistor during startup for a hotter spark.

Re: Ignition switch

Posted: 08 Jan 2021 10:09
by yenpit
510rob wrote:
07 Jan 2021 15:20
Norm, be careful with this. Some of the old key switches lose power between start and run; if the power drops out when you move from run to start then back to run, the ECU thinks it has been turned on three times and it dumps three quants of priming fuel via the injectors and causes all sorts of head-scratching, not to mention the ECU seems fine, then you crank and it takes a few seconds for the engine to light, then it stalls when you drop the key back to run - a nightmare for troubleshooting.

A 280ZX switch will mount in place of a 510 switch and should not have any interruption to the black/white power wire as you move between start position and run position.
I was curious about the ignition electrical switch for the 280ZX...........according to rockauto & Beck Arnley, the electrical switch #201-1174 is the same for the 70-73 510 & the 280ZX. Wonder if the difference is in the vehicle wiring and/or ECU of the ZX?

Re: Ignition switch

Posted: 08 Jan 2021 17:00
by 510rob
I think it is just the same type of part that was manufactured years later and it made more sense to add a stripe contact rather than a point contact. Or maybe I drank the kool-aid because it was Jeff that told me about it years ago in the first place! :P

Re: Ignition switch

Posted: 11 Jan 2021 06:41
by icehouse
yenpit wrote:
08 Jan 2021 10:09
510rob wrote:
07 Jan 2021 15:20
Norm, be careful with this. Some of the old key switches lose power between start and run; if the power drops out when you move from run to start then back to run, the ECU thinks it has been turned on three times and it dumps three quants of priming fuel via the injectors and causes all sorts of head-scratching, not to mention the ECU seems fine, then you crank and it takes a few seconds for the engine to light, then it stalls when you drop the key back to run - a nightmare for troubleshooting.

A 280ZX switch will mount in place of a 510 switch and should not have any interruption to the black/white power wire as you move between start position and run position.
I was curious about the ignition electrical switch for the 280ZX...........according to rockauto & Beck Arnley, the electrical switch #201-1174 is the same for the 70-73 510 & the 280ZX. Wonder if the difference is in the vehicle wiring and/or ECU of the ZX?
The difference is the blue with black stripe power, it always gets power unlike the 510 that switches it off, since it's used as a ballast bypass. If you run it on a points car they will burn out.