city vs. hwy mpg

[F150]

I am flying under the radar. I have no sensor modifications yet. No bubbler. Simple generator hooked direct to intake after the throttle. Vacuum gage reads 20inhg at idle and 15inhg with acceleration.

Hwy: I went from 13 to 19mpg!
City: I have no gain, maybe even a decrease. Around 10mpg.

Any thoughts or ideas?

[Smith03Jetta]

I've experienced similar results. It is most likely that the Gen is making too much HHO when at lower RPMs.

[F150]

I dont have a tach. But i wonder if Im actually running lower RPMs on the HWY. And constantly accelerating to shift gears in town.

[redneckgearhead34]

ok a possible theory of this could be the fact that you using o lower air:hho mixture when you are on the highway as compared to in the city. So when you are in the city your O2 sensor make your fuel mixture to rich for an sort of mpg gain

[F150]

More air with acceleration + my HHO. = Too much O2?

That could be. Instead of O2 extenders has anybody tried simply disconnecting the sensors at the plug-in? Youd get a check engine light Im sure, but would it work?

[bigapple]

if i was u, rather than buying electronic modifiers or O2 extenders, id T that hydroxy line and have it running to vacuum and the other to the intake tube before the throttle body. since u lose vacuum at higher speeds and air intake vacuum increases, itll make up for the loss. and since ur intake doesnt pull as much air at idle, the vacuum will make up for that as well

i think putting less stress on one main line and having it go two directions mite work. if not, its not like its an expensive modification.

looks like ur using gas line. go to autozone and get another foot of the stuff and tee it off with a T-barb at a hardware store

maybe this will solve ur problem. good luck