Extremely Bad Gas Mileage

happy thanksgiving maddie!

 

New theory. If the tank bladder was leaking, but the gas was still in the tank, that would gradually reduce the amount of room available in the bladder for gas. So, while continuing to get the same mpg, one would gradually get fewer milers per tank. However, the tank must have some sort of vent (probably at the highest point), to allow the bladder to expand and contract. So, I would expect the gasoline trapped between the bladder and the tank itself would get forced out of that vent when gas gets pumped into the bladder.

 

Going to have to disagree on this one. A very dirty air filter can and WILL affect your fuel economy, how could it not. Yes, mass airflow, MAP, O2, throttle position and a number of other sensors trim fuel/air air ratios. They work to achieve the best AFR as mapped per the ECM. All true. That being said, it has it's limits. It was designed with the assumption of a free flowing access to fuel and air. Limit one of those two things, you get poor engine performance, and less power. On most cars it's pretty obvious with crappy performance. On a Prius, not so much because your traction battery is working a bit harder picking up the slack, and your fuel mileage suddenly nose dives. I have seen it happen. Anytime you restrict your air flow your going to lose power or economy

Your welcome to test this at home. In any Fuel injected car you like. Find a short drive, figure out the MPG. Go home and cut a sheet of cardboard the size of your air filter, poke a few holes in it with a screwdriver just for fun. Open your air filter box and put it over the top of the air filter and close it back up. Take that same drive and let us know what your MPG was.

Any of you old school carb guys will know it's like driving with the choke on.

 

Your statement is not what Doug said, so your argument falls a bit flat.

This difference is picked up by John in his comment:

 

If it's VERY dirty, then maybe. And with older cars, yes. But with computer controlled fuel injection and the myriad sensors, I've read that moderately dusty fuel filter will actually raise mpg. The computers see the reduced air flow, accordingly reduce amount of fuel injected, and you've essentially down-sized your engine.

 

It's not an argument, it's physics.

 

Argument as in a reason or set of reasons given in support of an idea, action, or theory.

Your argument is a different context to the original statement. That is to say, the original argument mentioned a dirty filter as opposed to your argument mentioned a clogged filter. Two different things.

Yes, it's physics, but the physics in the first instance is not the same as the physics in the second instance and in fact, both are correct.

 

Lol why announce that just do it.

 

I can't believe how many people post about gas mileage and never calculated it.

As posted earlier, miles per tank full is not accurate. Your screen isn't accurate ether. My screen says I'm averaging 45+ but when I check (miles driven divided by gallons put in), 32-37.

I've had two other cars that show MPG. Both overstated actual by far.

 

But due to the bladder you may not put in what you actually used so I don't know how you can say THAT method is accurate. The MFD reads the ecu which I have verified is close to what the MFD is displaying when I am using Torque.

In the winter I can only put about 6 gallons in. I've read in some threads that to reset you fill it up and run it to one blip twice and that can reset the bladder but I only get about 250-300 miles per tank in the winter. The temps go freezing to below freezing where I am.

 

If you calculate tanks, for a few tanks, it gets increasingly accurate. A single tank yeah it can be off, but it balances out on the next one.