Fuel Pump Problem Has me baffled?
 

Well this is now beyond me. After two days at Oulton Park I am still no better off in fixing this problem on the 996. I spent more time yesterday in the recovery truck LOL.

Set off and all is good then after 5 or 10 mins (sometimes less) the bike will misfire/refire and stop. Then the bike will not start, it turns over fine but the fuel pump doesn't run, sometimes makes an attempt to run but not as it should do. Leave it for a while and it will start and run fine. Completely predictable in it's unpredictability.

I have changed every relay/fuse/sensor/ecu/chip/regulator/pump/filter/coils in fact I think everything there is to change.
Only thing left is the harness? or magic dust.

Neil.

Do you have a spare pump you can try?.... These are similar problems to when my pump was playing up at Mallory in 2010 (on a 583, but even so). We replaced everything and wiggled every part of loom with engine running.... Eventually cured with new pump (mine had an elec pump on it). Mine would tickover fine and run fine for 5 laps... Then the gremlins would strike.

Or the tank breather?.... Run it with cap left slightly open. It is a long shot.... But just maybe enough of a vacuum could be formed to overpower the pump?

Neil you can borrow anything you need off my 916 try the complete tank with pump maybe?

I have a spare tank (my trackday tank) you can borrow if you want to eliminate/confirm it's a pump/breather/line problem?

Thanks guys but I have had two different pumps and press regulators on the bike with no change. All pipes/hoses are clear and intact. :confused:

Is your vent valve fitted the correct way round? Are the vent hoses clear? Is the tank breather (the lines in the tank itself) clear? Are the fuel lines kinking when you replace the tank? Is there a kink in a fuel line futher down to the throttle bodies?

Yep all clear.
If the harness is a possible issue I was considering this.
The pump has a 12v feed when the ignition is turned on. The ECU then turns the earth on until the pump is up to pressure then turns it off. When the ECU gets a signal from the ignition sensor it turns the earth on again so the engine will run. So if I run a seperate fused/switched live from the battery to the pump and a seperate earth from the pump to the corresponding pin on ECU this in my mind would eliminate any of the existing wiring and possible problem?

Chafing wire. Had the wire on the fuel pump connector chafing on the top the engine on my 999.

Also try a new fuel pump relay?

I was going to say it sounds like the Pump Neil as I have just replaced mine, I had the same symtons as you. Misfire then ok, then sometimes wont start then nothing wrong at all then finialy packed in all together on a ride out, ( even the mighty Skids did'nt carry one of those with him on a ride out )
But reading down it seems you have replaced the pump ?
Sorry that was not really helpful was it lol
Get the meter out and rattle shake the bike about to see if the readings change drasticaly.

Craig