Can Car Computer Prevent Higher MPG?

Discussion in 'Fuel Economy' started by 404-419, Apr 19, 2014.

  1. 404-419

    404-419 Member

    I spoke with a friend yesterday who drives a 2001 Daewoo Nubira with 71K miles on it. He told me about how he installed one of those "water for gas" systems and that when he would fill up, he'd go from the normal 28 MPG up to 64 MPG on the FIRST HALF of the tank and for the second half the MPG would tank such that his average was back at 28 MPG for the whole tank.

    He told me he discovered that his car's computer was "dumping fuel directly into the intake" and wasting fuel to obtain the max MPG of 28.

    Does anyone know anything about how these computers work and is it possible that they can prevent increased MPG?

    Thanks in advance for any clues....
  2. RedylC94

    RedylC94 Well-Known Member

    If that were true, he could consistently get 64 mpg by refilling the tank every time it gets down to half-empty.

    I'd say your friend is severely confused, if he sincerely believes what he told you.
  3. 404-419

    404-419 Member

    Well that's what he does but the real question is to learn if any car computers can really stop you from getting higher than average MPG.
  4. brick

    brick Answers to "that guy."

    The computer's job is to monitor engine conditions to administer the correct amount of fuel to match the amount of air being taken in. It does that primarily based on an air flow meter in the intake and a series of oxygen sensors on the exhaust. Achieving the correct mixture is all it cares about, and in an old Daewoo I would be surprised if any computer has any idea whatsoever what his fuel economy is. His story is a bunch of nonsense. He got 28mpg before, and he's still getting 28mpg because his water contraption doesn't actually do anything.
  5. 08EscapeHybrid

    08EscapeHybrid Moderator

    I agree. The contraption he installed on the vehicle isn't doing anything, and he's blaming it on the vehicle's computer.
  6. 404-419

    404-419 Member

    Ok now I have another friend who doesn't have any contraptions. He uses the same fuel additive that I use. When he first started using it he got a 5-10 mpg increase. He calculated his mpg using paper receipts and by recording the mileage with every fill up. Then his battery went dead and he installed a new one. Since doing that his mpg has decreased back to what it was before using the fuel additive even though he still treats his gasoline.

    I've talked with other car guys and they say that on newer model cars there are engineering controls that aim to provide the high mpg number on the sticker. And the computers take special care to always meet that number....never exceed it.

    Do you agree that there could be engineering controls in place that prevent higher than published mpg?
  7. xcel

    xcel PZEV, there's nothing like it :) Staff Member

    Hi Sherri:

    If I place a cardboard box under the hood of someone's car and say it helps them get better mpg, it will because they will be driving more efficiently wondering about the black box.

    There is nothing that works other than changing your car (tires, tire pressures, lubricants, and weight reduction can help) or changing your driving habits.


  8. 404-419

    404-419 Member

    Well I have to disagree. I was able to increase my MPG from 10-12 to 19-20 with a fuel additive that lowers the activation point so that my fuel burns at a lower temp and more completely. It's been around for over 15 years. I did not change my driving habits and I've used it for over 18 I hardly even think about it any more. I'm just suspicious that an engineering control could possibly exist that prevents higher than average MPG. Do you know anything about that?
  9. xcel

    xcel PZEV, there's nothing like it :) Staff Member

    Hi Sherri:

    Your ID was a phone number pointing to the Atlanta area. Probably not a good idea to use that string so I removed the last 4-digits.

    And good for you. The Auto Manufacturers have spent at least $20 billion in just the last decade to achieve a 40% increase in fuel economy. You should sell your elixir to the auto manufacturers for at least $1 billion as a guess? The EPA highway of the 2009 Dodge Durango 4x2 and 4x4 with the 5.7L Hemi is 20 and 19 mpg respectively. You have now caught up to what the automakers provide everyone else with the liquid "stuff".

    Please do not add the 4-digits back to your ID or your signature.

    Last edited: May 13, 2014
  10. 404-419

    404-419 Member

    I don't use any liquid stuff. I had a clean car all tuned up, perfect tire pressure and clean oil, etc. I don't carry junk in my car. All that led me to only 10-12 MPG. But that's not what I'm talking about here. I'm here trying to learn from the experts. I'm not asking you to believe me or care.
  11. xcel

    xcel PZEV, there's nothing like it :) Staff Member

    Hi Sherri:

    I care deeply. Just do not add the last 4-digits to your sig or your login ID ever again. It is the worst kind of advertising.

    Contact Sherri at 404-419-xxxx
    I Will Return Your Call

  12. some_other_dave

    some_other_dave Well-Known Member

    On the off-chance your question is serious:

    No, there is no control that enforces a maximum fuel economy. In general terms, the control of that is in the driver's right foot, and between his/her ears.

    Pick a "maximum", and chances are that someone on this BBS beats it regularly. For instance, almost all of the active posters here beat the EPA "highway" ratings in their combined city and highway driving. Many beat the "highway" rating with almost all "city" driving, in fact.

  13. 404-419

    404-419 Member

    Thank YOU!

    Yes I'm totally serious and looking for an honest answer.

    I appreciate you taking the time to share your thoughts.


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