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Tapping ignition circuit

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by Oblin Goblin, Oct 30, 2002.

  1. Oblin Goblin

    Oblin Goblin 1/2 ton status

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    Anybody know a good place under the hood to tap into the ignition circuit? I know there are a couple terminals in the fuse panel but I was wondering if there are any terminals under the hood that I could use. I'm trying to find power for an electric fuel pump I've installed.
     
  2. TopOff

    TopOff 1/2 ton status

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    Should be able to find one on the ignition power that feeds the distributor. However, since your feeding a fuel-pump. I would setup a relay. Have the relay turn on by the ignition power (before a resistor if your so equipped). Feed the main line of the relay (to the pump) from a good battery or the terminal connector on your firewall (atleast it's on my firewall).

    I would not want a fuel-pump to screw with the coil signal, hence the use of a relay, plus it would give you a better integrity 12v to the pump!

    BTW: Some racers use this relay to power the ignition circuit too! If you measure your ignition circuit you might find you are only getting 11.5 volts to it. Put it on a relay and you might get 12V +. Times 100 winds on the coil it could be a gain in spark and MAYBE some power gains. Although you would be better off adjusting your timing for power, and gas mileage.

    whoops long post. sorry. /forums/images/graemlins/cool.gif
    Good luck.
     
  3. Oblin Goblin

    Oblin Goblin 1/2 ton status

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    I forgot to mention that this is a Diesel, so I don't have a distributor. I was hopping there might be a juntion block or terminal on the firewall or somthing, or better yet somthing on the chassis tword the back of the truck near where I have the pump mounted.
     
  4. Dunc03

    Dunc03 1/2 ton status

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    If your putting the fuel pump near the rear you could splice into the rear window power, if you have it. There is a bundle of wires that comes down on the driverside that goesto the rear. In that bundle there will be a set of three wires that are blue, orange/Black, and Pink/Black. The oragne and the pink are your power sources. One is a constant hot and the other is a keyed on source. I don't remember off hand which is which, but you can track them back to the fuse panel.
     

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