I'm just not buying this. How could that little bit of acetone increase mileage that much? It doesn't increase the fuel's specific energy (probably decreases it) any significant amount, and I can't see where it would likely make the fuel atomize any better. Nope, I'm not buying it.
As to the check engine light, if you want your vehicle to run right and get the best mileage you should probably get that sort of thing checked out. If the O2 sensor is faulty the fuel injection system can't adjust the fuel-air mixture as effectively as it should.
i think the theory is that the acetone makes the gasoline more volatile - it vaporizes quicker in the combustion chambers. I think there might be a more complete burn in the cylinders. Very efficient cars that get high mpg don't seem to get much of an increase in the mpg, and I think it is because the fuel is more efficiently burned....the volatility that the acetone increases, isn't a factor....just a guess.
I own a Toyota 4-Runner. Needed a new oxygen sensor to pass inspection. Toyota wants big bucks for a new one.
My mechanic called a help line (can't remember which one; costs $3/minute). Their Toyota expert suggested he clean the oxygen sensor element with carburator cleaning fluid (maybe it's acetone? don't know).
He did, and... it worked! No check engine light for three months (knock wood).
(steely)
I'm skeptical too, but not opposed to reading up on it. The article I linked to in post 16 says it eliminates the surface tension of the gasoline in connection to the cylinders & piston allowing it to vaporize more efficiently. Isn't that similar to what an NOS system does - simply makes your gasoline burn more efficiently (just in a different manner.)
But if it is burning/combusting more gasoline than the pistons/cylinders are designed for, wouldn't that create unforseen stress and wear (like an NOS system can.) Or are we talking about gains that are too slight to make much difference?
Do you know what octane rating is? It is the opposite of what most people think.
Most people assume that a high number means that the gas burns hotter/faster, but the truth is that there is more retardant added to the fuel to make it burn slower/longer thereby producing more force against the piston for a longer period of time.
Read the article linked in #16, Toronto.
I had a check engine for a long time, and overheating when pulling a heavy trailer up long steep hills. It was dismissed by dealers everywhere until I put a rebuild engine and transmission in and the light stayed on. It turned out not to be the O2 sensor, it was a clogged catylitic converter. (That may have been the problem on those long hills, or alternatively the exhaust gas temp may have gotton so hot on these grades that it melted the element in the converter. Anyway, it sure runs better with the converter element knocked out. The check engine light comes on sometimes and goes out sometimes, but mileage is increased dramatically, like maybe the acetone helped melt out the converter?
One possibility: Maybe the acetone fakes out the O2 sensor into thinking the mixture is too rich, and it adjusts the fuel injectors to cut back a bit, causing the engine to burn a bit more lean?
"As to the check engine light, if you want your vehicle to run right and get the best mileage you should probably get that sort of thing checked out."
One of the things that can cause a check-engine light (not by any means the only one, unfortunately) is having the gas cap left loose on the car. Most fuel-injected cars use a pressureized fuel system, these days.
As for the acetone thing, with gas prices being what they are, I'm going to try it.
I don't know the specific chemistry, but you can significantly raise vapor pressure by mixing liquids.
Water mixed with alcohol evaporates much more quickly than just straight water.
Since it is the gas fumes that burn, not the liquid, anything that helps more gasoline get into the vapor state in the carbeurator would improve engine efficiency.
However, acetone is quite good at dissolving rubber and plastic, so I would be too nevous about running it through fuel lines myself.
"...I'm just not buying this..."
Does the acetone improve mileage on new engines as well as on older engines? I am thinking that the acetone might be cleaning the fuel injection system and making it more efficent. 0.25% acetone in gasoline (10ml/gal = .33 oz/128 oz 0.25% acetone) is, I would think, insignificant in terms of energy effects, unless there is some synergism going on that we don't understand.