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Last week the bike was running fine, then all of a sudden it would not start. During that time the only problem was the fuel relay was not getting the ground signal from the ecu. I went to start the bike and no spark! Replaced the ecu and now the bike starts but it still will not power the relay. What are the odds of another ecu doing the same thing?????????? The ecu has to send a ground signal to the fuel relay so it will power the pump. The only way is with the relay bypassed. Does anybody know if anything else would cause this? The diode in the ignition is sending 9v like it should, bas is doing its job, is there anything else in this system that would stop the ecu from letting the relay do its thing. And yes the kill switch is good, and the start relay is sending 12v to the fuel relay!!!!!!! Just will not send 12v back on the brown wire to run the fuel pump. I am afraid to keep the jumper wire in the relay because I am not sure if that is what killed my last ecu. Or else is there anybody that has an f4i 2001-2003 that could test my ecu if i send it to you? I am in Southern New Jersey but nobody has my bike to test it in, thanks for any help.
 

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Last week the bike was running fine, then all of a sudden it would not start. During that time the only problem was the fuel relay was not getting the ground signal from the ecu. I went to start the bike and no spark! Replaced the ecu and now the bike starts but it still will not power the relay. What are the odds of another ecu doing the same thing?????????? The ecu has to send a ground signal to the fuel relay so it will power the pump. The only way is with the relay bypassed. Does anybody know if anything else would cause this? The diode in the ignition is sending 9v like it should, bas is doing its job, is there anything else in this system that would stop the ecu from letting the relay do its thing. And yes the kill switch is good, and the start relay is sending 12v to the fuel relay!!!!!!! Just will not send 12v back on the brown wire to run the fuel pump. I am afraid to keep the jumper wire in the relay because I am not sure if that is what killed my last ecu. Or else is there anybody that has an f4i 2001-2003 that could test my ecu if i send it to you? I am in Southern New Jersey but nobody has my bike to test it in, thanks for any help.
sounds like a bad relay to me.
 

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the relays were tested, and are good. to confirm we swapped them with the headlight relay, headlights worked and fuel pump still did not. then switched with starter relay, same thing. so all good relays work except at the location of the fuel cut relay. that would only confirm the ecu is not sending the proper signal to relay to open. it has to send ground to let it close so it can power up from starter relay and send 12v on brown wire to fuel pump. i can not believe 2 ecu would fail the same way. thats why i was hoping sombody local or whatever could test them for me, thanks
 

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This happened to my bike yesterday, tried turning it on and the motor would only keep turning....Fuel pump relay would not prime, and the sparkplugs had no spark...so i got my light tester hooked it up to the ground on the batter while the key on "ON" started testing wires on the Engine cut off relay...while testing it with the tester i had touched one connection (Red Wire with White) i think and the Fuel pump started priming...tried turning the bike and it started right up....So the relay needed some ground..hooked up a wire from the Battery to the relay and Vuala.! the bike works fine now.

Hope this helps.
 

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the relays were tested, and are good. to confirm we swapped them with the headlight relay, headlights worked and fuel pump still did not. then switched with starter relay, same thing. so all good relays work except at the location of the fuel cut relay. that would only confirm the ecu is not sending the proper signal to relay to open. it has to send ground to let it close so it can power up from starter relay and send 12v on brown wire to fuel pump. i can not believe 2 ecu would fail the same way. thats why i was hoping sombody local or whatever could test them for me, thanks
Have you tried another ECU on it to see if thats the problem? I would check the wiring. If you have lost 2 ecu's to the same issue then i would trace the wiring and be sure its not touching metal anywhere or cut or anything. If you don't find anything with the wiring my next step would have to be try another ecu. sucks you have lost 2 already though. good luck and keep us posted.

This happened to my bike yesterday, tried turning it on and the motor would only keep turning....Fuel pump relay would not prime, and the sparkplugs had no spark...so i got my light tester hooked it up to the ground on the batter while the key on "ON" started testing wires on the Engine cut off relay...while testing it with the tester i had touched one connection (Red Wire with White) i think and the Fuel pump started priming...tried turning the bike and it started right up....So the relay needed some ground..hooked up a wire from the Battery to the relay and Vuala.! the bike works fine now.

Hope this helps.
so you just made your own ground for the relay??
 

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Have you tried another ECU on it to see if thats the problem? I would check the wiring. If you have lost 2 ecu's to the same issue then i would trace the wiring and be sure its not touching metal anywhere or cut or anything. If you don't find anything with the wiring my next step would have to be try another ecu. sucks you have lost 2 already though. good luck and keep us posted.



so you just made your own ground for the relay??
Yes sir...i get no error codes or nothing so the bike is running fine with no probs...
 

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Yes sir...i get no error codes or nothing so the bike is running fine with no probs...
That's pretty crafty. Nicely done. Maybe this will help Squidtrap out in his dilemma. :thumb:
 

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Discussion Starter #8
That's pretty crafty. Nicely done. Maybe this will help Squidtrap out in his dilemma. :thumb:
Tested both ecu's today on a running bike. One has no ground to fuel cut relay the other same w/no spark. That one is cooked. The one w/no ground for now I just jumped the fuel cut relay and the bike runs fine. I might try the ground to the relay, but yes that is it. The ecu sends a ground signal to the relay through the brown wire which allows the relay to close using the power from the engine stop relay. Kinda confusing but at this point I know every inch of this f4i and almost every wire and the voltages they should deliver. I might just keep the relay jumped just so nothing happens to this ecu and keep it for a spare. I have a guy who has one and he said brieng bike to him and he will put his ecu in my bike to prove it is good. Just a little help for everyone, if you are going to buy a used ecu put it in your bike to make sure it is good because thats how i ended up w/the 2nd one that will not prime. It was bought off a honda forum and he swore it was good (NOT) so now i will go through paypal and they will refund my money and go after him. Thanks everybody,ed
 

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Tested both ecu's today on a running bike. One has no ground to fuel cut relay the other same w/no spark. That one is cooked. The one w/no ground for now I just jumped the fuel cut relay and the bike runs fine. I might try the ground to the relay, but yes that is it. The ecu sends a ground signal to the relay through the brown wire which allows the relay to close using the power from the engine stop relay. Kinda confusing but at this point I know every inch of this f4i and almost every wire and the voltages they should deliver. I might just keep the relay jumped just so nothing happens to this ecu and keep it for a spare. I have a guy who has one and he said brieng bike to him and he will put his ecu in my bike to prove it is good. Just a little help for everyone, if you are going to buy a used ecu put it in your bike to make sure it is good because thats how i ended up w/the 2nd one that will not prime. It was bought off a honda forum and he swore it was good (NOT) so now i will go through paypal and they will refund my money and go after him. Thanks everybody,ed
Awesome that u fixed it.. m bike worked fine after i did that. glad i was able to help...if i did lol
 

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Tested both ecu's today on a running bike. One has no ground to fuel cut relay the other same w/no spark. That one is cooked. The one w/no ground for now I just jumped the fuel cut relay and the bike runs fine. I might try the ground to the relay, but yes that is it. The ecu sends a ground signal to the relay through the brown wire which allows the relay to close using the power from the engine stop relay. Kinda confusing but at this point I know every inch of this f4i and almost every wire and the voltages they should deliver. I might just keep the relay jumped just so nothing happens to this ecu and keep it for a spare. I have a guy who has one and he said brieng bike to him and he will put his ecu in my bike to prove it is good. Just a little help for everyone, if you are going to buy a used ecu put it in your bike to make sure it is good because thats how i ended up w/the 2nd one that will not prime. It was bought off a honda forum and he swore it was good (NOT) so now i will go through paypal and they will refund my money and go after him. Thanks everybody,ed
Hey that's great news. Always glad to hear. happy you got her running. keep us posted if you have any more issues at all. hopefully we helped you out. if we did give us some rep haha.
 
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