I broke my chain two Saturday's ago and after receiving the wrong chain set I finally received the correct one Tuesday. Got it on, went to start the bike and it fired right up but was running like crap. Last night after troubleshooting I found no power going to the fuel pump. Jumped the pump and it works great, checked continuity to ground, good. Traced the wire to a relay just in front of the computer and it is good for continuity as well. Checked the connector going into the relay and zero power of any type. I didn't have time to trace those wires to see where they go and I need to get a full schematic for the bike...

Anyone had this problem? I am hoping there is a hidden fuse I'm missing or another relay in front of the one by the PCM that is bad...

 

that relay you found only gets power when the coils get power. ( aka. It only turns the pump on and runs it when bike is started )

Hope that helps you a bit

 

that seems like a stupid design to me... having the pump come on to prime the system prior to start up seems to work for every other vehicle i have ever worked on...

ill check power on it when Irene leaves the area and i can un pack the garage and get to stuff.

if i am getting power on start up then ill let it work that way and just make sure i start the bike every couple of days. i think thats the biggest issue i had was 9 days of no start to keep the fuel system primed.

if no power then it will be time to start chasing wires (option a, and i hate wires) or to wire in my own set up with a relay controled by the key.

i honestly dont think the pump is running because i had a notacable power difference with my jumped pump setup vice the pump not running at all, i had the same power. i guess we will know on sunday or monday...

 

what are you riding? the f3's run on pressure and don't prime when you turn the key on. It's a very low pressure pump and from my understanding doesn't start running until there is a pressure differential(getting on it or whatever else) if your bike is fuel injected thats something different all together. A couple of my buddies have f4i's and 600rr's and those prime when the key is turned on

 

I suspect that most everything you've worked on was fuel injected. I'm assuming that you've got an F3 (since you posted in this forum). F3's are not fuel injected, but have carburetors. Unfortunately they have an issue with the contacts on the fuel pump going bad, but it's easily fixed. If the pump ran when you hot wired it, then it's probably fine.

How do the plugs look ? You said it's running like crap, the plugs could be fouled or one of the floats might be stuck.

 

I'm a jerk... Bike is a 95 f3...

Plugs and air filter are good. I was riding today and found out my fuel tank isn't venting. Bike started coughing and sputtering like it was starving for fuel, pulled over and started messing with it. Went to open the tank and had to pull it open only to he's a vacuum sound of air going in. Just drained and flushed the tank and had clean fuel in it. Checked the drain lines and they were clean but now I'm wondering if my petcock is messed up. I'll pull it again ASAP to see if I can figure out what is going on

As for power to the pump, I checked the wires going to the relay while the bike was running and only got .6 volts at idle and 9.6v under throttle. Is that normal?

 

Yes, that is normal. You can't read the voltage with a regular meter going to the pump because it is a pulsed signal. It only gets power each time the coil fires for plugs 2 and 3.