Poor fuel mileage

[willy]

Friend has a 2009 ultra with V&H true duals,Rinehart mufflers,A/N Big Sucker,Power CommanderV.Been on dyno 3 times.Runs good and spark plugs look good but only getting 35mpg.stock he was getting around 47mpg.I have similar set up on my 2010 Limited and only lost about 2 mpg.His bike is set up at 13.8 fuel ratio and the dyno sheet looks good.We ride together alot and he doesn`t ride hard or throttle jockey alot.Do the stock O2 sensors have enough range to adjust if he unhooks the P/C V and puts stock air cleaner back on to see what he gets with just the true duals.Any suggestions would be a big help.Thanks.

 

[Dr. Dolittle]

I would say he should have no problem running through a tank or two of gas to see how much his mileage changes.

 

[willy]

Thanks Dr.Dolittle,we tried that and bike ran terrible.Think maybe the tuner disabled the O2 sensors.

 

[TripleJ]

I read your other post where you asked if it was ok to unhook the PCV and try running the stock A/C and 02 Sensors. This post sounds like you left the PCV hooked up and ran the bike with the 02 Sensors hooked up at the same time.

I would not be surprised if the bike ran poorly that way. The PCV is meant to run with 02 Sensor Eliminators in place. Running both hooked up at the same time defeats the purpose. One or the other but not both.