Results 1 to 20 of 38

Thread: MAF flow effects

Hybrid View

Previous Post Previous Post   Next Post Next Post
  1. #1
    Join Date
    Apr 2007
    Location
    Lubbock,Tx.
    Posts
    162

    Default MAF flow effects

    If you were to increase the flow across the MAF sensor what effects would it have over the numerous interlinks (injector volumn, EGR valve position, timing etc.) in the PCM?

  2. #2
    Join Date
    Apr 2007
    Location
    Lubbock,Tx.
    Posts
    162

    Default

    Surely someone has some idea of what would occur.

  3. #3
    Join Date
    Apr 2001
    Location
    CA
    Posts
    13,573

    Arrow

    It will defuel sooner. The actual air volume would be less than the perceived, so it would "think" it has too much air for the fuel/power output. EGR position would not likely be effected much, if any, but could go nuts 'cuz the output doesn't match the input. It's a delicate balance, and if you lie to it w/o computer intervention, it'll throw a fit (SES, limp, etc.).

    Bad idea.
    1985 Blazer 6.2
    2001 GMC 2500HD D/A
    dmaxmaverick@thedieselpage.com

  4. #4
    Join Date
    Mar 2005
    Location
    MI
    Posts
    8

    Default

    It is not clear to me what you mean by 'increase the flow' across the sensor ? ?

    Do you mean that you would somehow 'trick' the sensor into sending the same signal it does now at higher flow rates? Why would you ever want to do that?

    The MAF is a Mass Air Flow sensor - it corrects for changes in air density due to humidty, altitude, and temperature to give an accurate measurement of the mass of air flowing [Kg per minute, etc.] in order to meter the proper amount of fuel through the injectors to maintain the correct air-fuel ratio.

    If what you mean is to physically increase the flow by removing restrictions, etc. then there should be no problem as long as you do not exceed the range of air flow that the MAF sensor was calibrated for. Not all sensors are universal - many have upper and lower limits, too high or too low and you will not get accurate readings.

    The MAF is one of the crucial inputs to proper fueling of any engine - it would be the last thing I would ever mess with.
    Jeff

  5. #5
    Join Date
    Apr 2007
    Location
    Lubbock,Tx.
    Posts
    162

    Default

    Quote Originally Posted by jmoser View Post
    It is not clear to me what you mean by 'increase the flow' across the sensor ? ?

    Do you mean that you would somehow 'trick' the sensor into sending the same signal it does now at higher flow rates? Why would you ever want to do that?

    The MAF is a Mass Air Flow sensor - it corrects for changes in air density due to humidty, altitude, and temperature to give an accurate measurement of the mass of air flowing [Kg per minute, etc.] in order to meter the proper amount of fuel through the injectors to maintain the correct air-fuel ratio.

    If what you mean is to physically increase the flow by removing restrictions, etc. then there should be no problem as long as you do not exceed the range of air flow that the MAF sensor was calibrated for. Not all sensors are universal - many have upper and lower limits, too high or too low and you will not get accurate readings.

    The MAF is one of the crucial inputs to proper fueling of any engine - it would be the last thing I would ever mess with.
    This post actually stems from another "LBZ Hot and Loss of Power", in which there were some good responses but not a lot of direction for what to do to find out what was causing such a loss of towing power.
    One response from a Banks Tech led to a phone conversation with same; and the basic recomendation was to relocate the MAF. He said that Banks had had some problems with their intake system in developement and found that when they located the MAF in the bend just before the turbo tract, and on the outside of the bend that they found good power gains and also found that the EGR valve pretty much stayed closed all the time.
    Fact or not I though it was something to check out and try; if I could get any other insight that seemed favorable.
    The position of the MAF on my LBZ (others too I assume) is on the inside of the first bend past the filter box. In this position the main velocity of course is on the opposite side of the intake tube; as with any hydraulic action the inside of any bend has a lower velocity than the outside. Depending on the configuration a vaccum can actually occur on an inside of a bend at some flow rates. (In chill water systems sometimes to the exent of air pockets and pump cavitation given the right proximity.)
    In any case it seems that Banks by their repositioning has increase the flow at the MAF dramatically. How does that work?----and is it possible that this could actually effect the EGR. Seems that the consenses here is that it could not.
    I'm still looking for the power loss----Killer Bee says I'm on a ghost hunt!!! But this ghost sure has some real power drawbacks---hot too.

  6. #6
    Join Date
    Jan 2007
    Posts
    299

    Default

    MAF is one the better inventions for a motor. The old speed density computers back when fuel injection first came out where a table of set values that couldn't take into account environmental conditions. Those motors were hard to add performance to since back then it was hard to rewrite the ECU tables. (OBDI was the only game in town).

    Now, MAF is much better because it allows the motor to dynamically change to the environment. Messing with that signal will either cause a LEAN or a RICH Condition. More Air = More Fuel, so if you trick the MAF to report more air than is going in, then you will have RICH condition, although the 02 sensors will rat out the MAF and the motor will DEFUEL to compensate for the mixed signals. This can cause a surging motor because the MAF and other sensors are battling each other.... Same thing can happen if an onxygen sensor is going bad.
    2007 Silverado, 3500HD, 4X4, CC, Long Bed, SRW, LMM Diesel, Navi, DVD, Roll-N-Lock Cover, ICI Running Boards, CoastalEtech GM Lockpick for DVD/Nav changes in Motion, Back-up Camera...

    2006.5 VW Jetta Special Edition TDI - Blue Graphite - European Spec VW Fact. Nav Radio.

  7. #7
    Join Date
    Apr 2007
    Location
    Lubbock,Tx.
    Posts
    162

    Default

    Quote Originally Posted by DmaxMaverick View Post
    It will defuel sooner. The actual air volume would be less than the perceived, so it would "think" it has too much air for the fuel/power output. EGR position would not likely be effected much, if any, but could go nuts 'cuz the output doesn't match the input. It's a delicate balance, and if you lie to it w/o computer intervention, it'll throw a fit (SES, limp, etc.).

    Bad idea.
    I don't understand how if it is reading more air that it would defuel, that sounds backward but that is why I'm asking------I don't know how it all interacts, but would like to learn.
    Does it not effect the timing?

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •