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MKSpeedlab

Keyed Power for EFI?

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I was wondering if anyone knows, or maybe they have installed an EFI system in their car, which wire under the hood would work for a keyed power that also stays on when starting. I have tried to look through some wiring diagrams but just gave myself a headache. I was hoping that the throttle position solenoid wire would fit the bit but was having a hard time testing. The car is a 72 although Im guessing there werent too many wiring changes over the years. 

Edited by MKSpeedlab

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Look for red/yellow wires on the engine gauge feed harness (outboard most female bullet on the 4 pin plug on the headlight harness). 


Let me check your shorts!

http://midlifeharness.com

 

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Sounds good, I will take a look tomorrow and see what I can find. Im guessing drivers side somewhere near the washer tank? Do you know if the throttle position solenoid would also work since its no longer on the car? I was looking at the wiring diagram and its a red wire with yellow stripes so is that the one your talking about? Its located on the drivers side of the intake manifold. 

Edited by MKSpeedlab

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Depending on the solenoid it is hot during run or when the A/C is on, but not during start.

The wire midlife directed you to meets both requirements. 

You can also tap off the I post of the starter solenoid (same circuit, same function, different place).

 


Bob

 

Tachs, Voltmeters, Headlight kits, Wiper delays and more at

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Rocketman's Classic Cougar (and Mustang) Innovations, LLC

 

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Ok, I'll have to see if I can find where the wire he mentioned is located. 

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10 hours ago, TheRktmn said:

Depending on the solenoid it is hot during run or when the A/C is on, but not during start.

The wire midlife directed you to meets both requirements. 

You can also tap off the I post of the starter solenoid (same circuit, same function, different place).

 

No, the I post would have only 9 Volts or so due to the resistor wire during the time the key is in RUN position. 

Another wire is the green/red wire going to the voltage regulator, but only if you have an ammeter in the dash cluster.


Let me check your shorts!

http://midlifeharness.com

 

Flamicon2.jpg

 

 

oldfart.png

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53 minutes ago, midlife said:

No, the I post would have only 9 Volts or so due to the resistor wire during the time the key is in RUN position. 

Another wire is the green/red wire going to the voltage regulator, but only if you have an ammeter in the dash cluster.

Oooo that might work nice, I the car does have the factory ammeter. Although it will likely change the ammeter to a voltmeter at some point. I will check for that wire first. 

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11 hours ago, midlife said:

No, the I post would have only 9 Volts or so due to the resistor wire during the time the key is in RUN position. 

Another wire is the green/red wire going to the voltage regulator, but only if you have an ammeter in the dash cluster.

I stand corrected.  I was thinking of activating a relay or soft switch like the MSD box, not  a constant power source.


Bob

 

Tachs, Voltmeters, Headlight kits, Wiper delays and more at

smlogo.jpg

Rocketman's Classic Cougar (and Mustang) Innovations, LLC

 

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That said, I likely will hook it to a relay to make sure the EFI is getting a nice clean 12v when the key comes on. I have heard that the EFI systems like things to be as clean as possible without any noise. 

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The green/red wire for the voltage regulator worked perfect. Note to self, dont buy relays off Amazon anymore. But after replacing the relay I was using with a quality one its working great.

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Founded:
July 2010

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From:
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