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Discussion Starter · #1 ·
So i have a cbr600rr 2003 and I just recently got it. It was a really good deal and I couldn't pass up. The guy wanted 50$ for it because it was just sat in his backyard since 2012. The bike was missing a lot and a lot of the bike was damaged. I replaced a lot but I'll only list the most important things ( electronic) I ended up replaced the wire harness, all relays, all fuses, the fuel pump motor, rectifier, radiator and fan, the batter, the bas, and the entire ignition.The only thing that is still there that is electronic is the ecu. And I bought the ignition off of ebay but I kept the original wiring from the old ignition because he lost the key. So the ignition does have the diode. I think that the only option that I have left is to replace the ecu but I didn't know what else I could do. I'll list what it does.

. Turns in the bike all switches are in the on position.
. All lights come on.
. Does not prime at all.
. Turns over.

I've tested the pump with a direct charge and it works. I tested the female connection where the pump plugs in and I get a continuous 4.83 volts. Please if you can help me I'd greatly appreciate it. I've been working on it for 2 months now.
Ps I know the motor is good because it only has 5k miles on it. ( that's really why I bought it)
 

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Hi and welcome! 馃憢

1. key ON. measure voltage at ECU connector's pink wire. Volts = ???
2. 4.83v @ pump is wrong. What's voltage at output terminal of fuel-cut relay?
 

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Discussion Starter · #3 ·
Hi and welcome! 馃憢

1. key ON. measure voltage at ECU connector's pink wire. Volts = ???
2. 4.83v @ pump is wrong. What's voltage at output terminal of fuel-cut relay?
I wouldn't know how to test that. I tested the fuel pump and where it connects too. And the relays all read 12 volts. It's hard for me to see colors so I've been trying to find the pin numbers. I'll go test the pink one and post it on here.
 

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1. take tank off, find ECU connector, back-probe connector where pink wire goes in. Key ON, pink wire voltage = ???

2. Trace fuel-pump wire where you measured 4.83v. to other end where it connects to fuel-cut relay. Then measure voltage there. If you're measuring +12v at relay and only 4.83v at other end, where did +7.17v disappear to along way??

BTW, did you get brand new OEM harness from authorised Honda dealer? If you got used harness, we'll have to test every single wire to make sure harness is fully functional. Otherwise, you're gonna be chasing troubles previous owners created just like original harnesss.
 
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Discussion Starter · #5 ·
1. take tank off, find ECU connector, back-probe connector where pink wire goes in. Key ON, pink wire voltage = ???

2. Trace fuel-pump wire where you measured 4.83v. to other end where it connects to fuel-cut relay. Then measure voltage there. If you're measuring +12v at relay and only 4.83v at other end, where did +7.17v disappear to along way??

BTW, did you get brand new OEM harness from authorised Honda dealer? If you got used harness, wel'll have to test every single wire to make sure harness is fully functional. Otherwise, you're gonna be chasing troubles previous owners created just like original harnesss.
I got the harness second hand so yes I will have to test the wires. And yea I thought it was super crazy that the volts just disappeared.
 

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Just to confirm, you measured output terminal of fuel-cut relay @ +12v? What was input terminal voltage?

If both same, then trace wire between relay and pump. Either it's got short to ground somewhere or wire is broken/corroded internally.
 

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Fried ECU doesn't explain 4.83v @ pump... that's your main problem.
 

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You want to test system as wired in working configuration. Otherwise tests aren't valid. For example bypassing pump. Not sure how you did that, but you'd have to do that full-time to ride bike. Such as holding test-leads/jumper wires on pump in order to make it run.

ECU's not problem because all it says is, "turn on pump". Which relay obeys and sends +12v to its output terminal. You've already identified problem. Now you have to figure out why that power disappears along way to pump. Trace wire between fuel-pump relay's output terminal all way to pump to figure out why you're losing 7v along way.
 

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Discussion Starter · #13 ·
You want to test system as wired in working configuration. Otherwise tests aren't valid. For example bypassing pump. Not sure how you did that, but you'd have to do that full-time to ride bike. Such as holding test-leads/jumper wires on pump in order to make it run.

ECU's not problem because all it says is, "turn on pump". Which relay obeys and sends +12v to its output terminal. You've already identified problem. Now you have to figure out why that power disappears along way to pump. Trace wire between fuel-pump relay's output terminal all way to pump to figure out why you're losing 7v along way.
Okay I understand I'll rebook over it and trace my harness to find the break or cut it the line.
 

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Greetings & Salutations, pindhaii87!!!
Might want to start our own welcome thread.
and let's see some photos of your bike!
 
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