Excessive fuel on my K75

[jody garris]

Several weeks ago I replaced the throttle position sensor, which cured my no fuel issue. Yesterday, while riding in upper NY state, I heard a loud "twink", such as the sound a compressed spring would make if it broke. I'm not sure if that is related or not, but an hour later we stopped for a bit, and when we restarted, it went briefly then quit, followed by the strong smell of gas, as in flooded. I pulled the plugs, which were saturated, cleaned and checked with good spark. There seems to be what I call an excessive amount of fuel when you crank the engine with no plugs in, enough to wet the ground in spots. Just wondering if I should be looking at the injection control unit? Any help greatly appreciated, Jody

[Bruce C]

Did you look around in here?http://www.ibmwr.org/ktech.shtml

[jody garris]

Thanks for the reply bruce, that was my starting point and didn't find anything. I'll keep digging

[ShovelStrokeEd]

I'm thinking fuel pressure regulator. As I recall they are vacuum piloted. Located on the end of your fuel rail. Check vacuum line going in, return line to the gas tank, both for good connections and no leaks/blockage. They are not all that expensive so replacement may be an easy form of problem solving.

[jody garris]

Thanks Ed, I'll try tonight

[ShovelStrokeEd]

Don't forget that the pressure regulator works in reverse to what you might first think. Less pressure at the vacuum port = higher fuel pressure. Could well be, given the age of the bike, that the diaphragm has failed. You should be able to see that from gasoline at the vacuum port. Using proper precautions, remove the vacuum line with the engine running, if gas comes out, immediatley kill the motor and beware of sources of ignition.

[jody garris]

Thanks Ed. I'll check the vacuum line for fluid, but it definately won't start. Just curious, with the injectors being a pulse type, the fuel would still be metered by the control unit wouldn't it? Thanks

[Paul Mihalka]

Another possibility is the air flow meter. It is a flap in the air box on top of the engine. It is held closed by a spring. Opening the throttle bodies generates vacuum pulling the flap open in proportion to throttle opening. If the spring is gone the flap opens and tells the injectors to supply max. fuel.

[ShovelStrokeEd]

Sure it will but, it won't get the proper amount of fuel if the fuel pressure is vastly different from what is expected. A leaking diaphragm will cause the fuel pressure to be too low so very little fuel will get to the combustion chamber. A plugged or collapsed vacuum line could act as a check valve and retain vacuum in the pilot diaphragm and cause fuel pressure to be too high, thereby dumping more fuel/pulse than should be there. The fuel could also climb into the system via the bad diaphragm and vacuum line resulting in uncontrolled fuel entering the intakes.

 

Best way to check all this is to connect a pressure gauge between the fuel rail and the regulator via a t-fitting. Nominal pressure is 3 bar or 42 PSI.

[jody garris]

OK Ed, I'm all over it. Let you know how I make out. Thanks again for all the help.

[jody garris]

OK, tore into it again last night, and broke a cardinal rule. I replaced a torn crankcase breather hose, cleaned the contacts on the fuses below the injection control, and removed, cleaned the plug on the inj. control. It started. Immediately shut it off because I figured the amount of fuel may have polluted the oil. Changed the oil and filter and did have a faint smell of gas, but the connection between the header and muffler had dripped a small puddle of gas on the floor. Pulled the header and dumped close to a cup of raw fuel out. Major overfueling. Now I'm torn, so happy to be riding, but wondering how long. If it does it again, I'll start one at a time while trying to start in between. Thanks again for all the help.