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Old 10-06-2004, 08:28 AM   #5
andy669
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Join Date: Jan 2001
Location: Moline Il
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A relay is installed to keep a more consistant voltage at the pump. It also eliminates the need for a heavy duty switch.

The relay will have 5 terminals, you will use 4 of them. 2 are the coil inside the relay. 1 of those will go to ground, the other will go to key on power. You can use light wire for these. 14-16ga will be enough. 1 of the terminals will go directly to battery power, and the other will go to the pump. For a Holley red, 12 gauge will probably be big enough to go to the battery, and the pump. I have several relays at the shop, and I can tell you which numbers go where after I look at one.

If I had to recall from memory which terminals would go where, it would go like this. 83 and 85 are the coil. When key on power is supplied, the coil is energized and pulls in a magnet which sends power from 87 (battery) to 87a (fuel pump).

You can get this relay at O'reillys or just about any other parts store. I'll double check the numbers today and post again.

Andy
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