fuel pump wont kick on

Started by Slytherin_Drifter, January 18, 2015, 12:54:21 PM

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Troll

#9

Here's the circuit:

Recovering H-D owner...W-650 Cafe' No excuses...Ride it or sell it to someone who will!

Troll

Quote from: Slytherin_Drifter on January 19, 2015, 16:57:34 PM

Ok i realize that when i turn the switch the relay.clicks. does that mean anything

Yes and no. Is this an aftermarket switch? The main relay is powered on with everything else...BUT the fuel pump is grounded through the computer. If the correct voltage is not seen on pin 6, I believe it is, then the path to ground is not completed. It is an 18 ga wire, yellow with a green tracer, as I remember. It DOES NOT show up in any wiring diagram, but if you pull the computer out, it will be there. John is correct, it's an anti theft measure found ONLY on EFI systems. I had a picture of that I posted last summer, so if you search my posts, you will see we have had this discussion before...

Recovering H-D owner...W-650 Cafe' No excuses...Ride it or sell it to someone who will!

Slytherin_Drifter

Ok i realize that when i turn the switch the relay.clicks. does that mean anything


John Hopkins

I think that resistor is designed as an antitheft device so that a thief can't just link the ignition wires to steal your bike If I remember correctly it is something between 100 and 400 ohms, maybe troll can get a bit closer on the value, if not start with 100 ohms and see how you get on from there..

Resistor color codes are bk br r or yl gn bu vio gy wht with bk = 0 up to wht = 9 so first color is first value, second color is second value and third number is the number of noughts or the multiplier..

Some resistors have an extra value band and are called four band resistors, the way to tell the difference is  three band resistor have three color bands close together and four band resistors have four color bands close together..There will be an additional two colors at the other end of the resistor but you don't need to know what they are for.

John.



Troll

You have one of the aftermarket switches? If so it's the same old issue with the resistor. If it's a factory switch, you may need to replace it. Here's the thing...and I learned this the hard (read expensive) way. There is one pin on the computer that is listed as no connection. In reality, it's a low voltage signal from the ign. switch. If it doesn't see the correct voltage, it won't ground the fuel pump to turn it on...The thunder switch that most people replaced the OEM switch with doesn't have this resistor, so you have to add it in. The wiring harness that comes with the thunder switch has the resistor in it, but they fail and/or loose connection, so the pin on the computer doesn't see the correct signal

Recovering H-D owner...W-650 Cafe' No excuses...Ride it or sell it to someone who will!

Slytherin_Drifter

Sorry. Connections on the back of.the switch. Red black and white


Troll

connections on the back of what?

Recovering H-D owner...W-650 Cafe' No excuses...Ride it or sell it to someone who will!

Slytherin_Drifter

Ok so i finally got my bike back together. Get everything hooked up and she fires right up. But i notice that my fuelpump isnt kicking on when i turn the switch. If i play with the connections on the back eventualy it cuts on. Anyone got any ideas


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