General question regarding a late model fuel injected bike and poor gas mileage

[528Hz]

Hey fellas, could any DFI gurus please chime in on this

Say you had a late model fuel injected fly by wire v-twin 1700 stock bike, with stock exhaust, no oxygen sensors from the factory, evap canister equipped with separator, secondary air injection crap, with a TPS, MAP sensor - so basically the usual late model stuff. And then one day you find that the avg gas consumption started to suck royally with the proper tire pressure, good spark plugs, clean air filter and no error codes from ECU whatsoever (sensor related). The spark plug audible clicking test has been performed and they audibly click indicating open/close. Fuel pressure has been checked and while the OEM recommendation is 43 psi at idle, it shows 44 psi at idle, so pretty close, could be the old gauge. The bike has no black, brown, or white smoke coming out the pipes neither at idle nor at applied throttle, but the fumes do somewhat smell different, it pops on deceleration and clearly consumes much more gas then it used to. So if it took 150-160 miles to empty almost a 5 gallon tank before, it now does so within 40 miles. If it was either of the sensors, the ECU wouldef thrown a code. IS this assumption incorrect in general? I went on randomly disconnecting various sensors and the error codes started popping up. Could 1-1.5 psi of this possible extra fuel pressure push more fuel through injectors then required and thus use up so much gas? I don't see how, but could the damaged evap canister with a separator somehow affect this kind of undesirable behavior? Is it evaoprating somewhere? There no fuel smell and no leaks anywhere. The spark plugs have brownish shade to them. This is quite a dilemma ::010::

 

[Buelligan]

deceleration popping is a sign of an exhaust leak. check your exhaust look for leaks. I would also pull the gas tank and empty it. Check the inside good for rust, debris, etc. Also check the fuel filter.

 

[Checkswrecks]

...the fumes do somewhat smell different,
...it pops on deceleration
...clearly consumes much more gas
...The spark plugs have brownish shade to them.

If it was either of the sensors, the ECU wouldef thrown a code. IS this assumption incorrect in general?

You didn't say what year or how many miles are on the bike.
Generally an exhaust leak affects one side or the other. Same for intake leaks.


Sensor degradation won't throw a code and it sounds like a change in mixture, so I'd try replacing the oxygen sensor. Simple enough to do on your own.

 

[Kevhunts]

Is this a water cooled engine?

 

[Karson]

i don't see how a bike could even run right at 40 miles on a 5 Gallon tank. some "decel popping" is normal, however excessive, all the time decel popping even at low rpms isn't. i can get my bike to pop like a mofo if i really wanted, and i know it's running right.

about the only thing i can think of checks already mentioned, change the downstream o2 sensor(s). easy enough to do, but again, i'm surprised that it even runs right. at that kind of fuel consumption, you'd come off the bike smelling like an oil refinery

 

[klunsford]

Also, if you are riding at altitude Decell popping is magnified greatly. All of my bikes do it a lot more when I ride in the mtns.

 

[autoteach]

clogged air filter
clogged fuel filter
leaking/poor spray pattern on injectors
clogged/blocked exhaust
wheel bearings
dragging brakes
vacuum leak

and I probably have missed some.

 

[Spider]

Any chance someone is stealing your gas? Hard to imagine the bike could even run decent with that much gas going through. You don't have a Powercommander or the like installed, right? Sounds like you're risking....wait for it....excessive carbon buildup.

Good luck!

Spider

 

[Don in Lodi]

Umm, I'd agree that the bike shouldn't be able to run with that much fuel going through it. I'd guess a fuel leak somewhere before guessing that it's consuming that much fuel. LOL, I'd guess that 'clicking' test was for the injectors, not the plugs.
On an EFI system that doesn't use O2 sensors to balance things, it will use the MAP to determine how much load is being demanded, combined with info from the TPS. The MAP sensor needs to go to ground or open before it will set a code. As long as it keeps reading a voltage in the 'range' the computer will try to figure out the issue between the TPS and MAP and make a best guess.
The plugs would be wet with fuel in short order, the engine would stumble and then die. You don't mention how well it does run. It sure doesn't sound like it's pushing that much fuel out the pipe.

 

[2daMax]

I was thinking high carbon deposits at the intake valves causing to ECU to run rich all the time. The deposits soaks up fuel spray, wasn't combusted all of it, and the ECU reads and determines that it is insufficient and continues to pump more fuel in a vicious cycle. The pops in the exhausts, are caused by either running too lean or too rich. In your case, it is probably too rich.

Try Sea Foam.

 

[steve68steve]

That's gotta be a fuel leak. Has the fuel line been disconnected/ reconnected lately? Can you smell gas when it's running?

 

[OldRider]

LOL. :

 

[Don in Lodi]

LOL. :

LOL, I wouldn't mind knowing the answer though.