- Joined
- Aug 14, 2014
- Messages
- 4,309
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- Location
- Madison, WI
- My Car
- 1971 Mach 1 w/408C stroker
This one is really strange. I think there are some extraterrestrial powers in my engine wiring.
Last night I unplugged the 3-prong connector between the engine and firewall. This is the one that connects the water temp, oil pressure and ignition wires (#16). As soon as I disconnected it, the EFI unit turned on :huh: . I noticed it because the fuel pump primed and confirmed that it is on by looking at the LCD unit. I connected it again and the EFI unit turned off. Disconnected it again, and the EFI unit turned on. And BTW, my ignition key was not turned and all the ignition powered components were off. As a background, in my setup, the ignition wire that goes to the engine (#16) is only connected to the EFI. This is used as a signal to turn the EFI on since it has a direct connection to the battery. My ignition wire does not connect to the coil since I have a CD ignition unit that gets the ignition signal from the alternator wire. This setup has worked for more than two years without issues. It is still working but something doesn't make sense. I measured voltage on the engine side of the ignition wire and indeed I get about 11 volts with the 3-prong connector disconnected :chin: . I went as far as disconnecting the EFI and still get 11 volts on #16. Where is this power coming from? I even disconnected the positive of all my electronics, including the stereo, subwoofer, alarm, EFI and CD ignition, and it still showed 11 volts. The only time the voltage dropped is when I disconnect the big fat yellow wire from the solenoid side. And to cap it off, if I disconnect the ground cable from the battery I still get about 0.5 volts. Just in case, I checked the voltmeter and it goes to zero if the prongs are removed.
:huh: :chin: :huh: :chin:
Last night I unplugged the 3-prong connector between the engine and firewall. This is the one that connects the water temp, oil pressure and ignition wires (#16). As soon as I disconnected it, the EFI unit turned on :huh: . I noticed it because the fuel pump primed and confirmed that it is on by looking at the LCD unit. I connected it again and the EFI unit turned off. Disconnected it again, and the EFI unit turned on. And BTW, my ignition key was not turned and all the ignition powered components were off. As a background, in my setup, the ignition wire that goes to the engine (#16) is only connected to the EFI. This is used as a signal to turn the EFI on since it has a direct connection to the battery. My ignition wire does not connect to the coil since I have a CD ignition unit that gets the ignition signal from the alternator wire. This setup has worked for more than two years without issues. It is still working but something doesn't make sense. I measured voltage on the engine side of the ignition wire and indeed I get about 11 volts with the 3-prong connector disconnected :chin: . I went as far as disconnecting the EFI and still get 11 volts on #16. Where is this power coming from? I even disconnected the positive of all my electronics, including the stereo, subwoofer, alarm, EFI and CD ignition, and it still showed 11 volts. The only time the voltage dropped is when I disconnect the big fat yellow wire from the solenoid side. And to cap it off, if I disconnect the ground cable from the battery I still get about 0.5 volts. Just in case, I checked the voltmeter and it goes to zero if the prongs are removed.
:huh: :chin: :huh: :chin:
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