Announcement

Collapse
No announcement yet.

Lame ass OBC question

Collapse
X
 
  • Filter
  • Time
  • Show
Clear All
new posts

  • Lame ass OBC question

    OK I know it's irrevelant but I've always wondered about this. How can you make the range function more accurate. When I fill up it claims I'm going to get like 438+ miles. Yeah well I get about half that so is there anything I can do or is this just 80's technology at its finest.
    "Condoms break baby, Deal with it."

    - Max Weinberg

  • #2
    I share your pain, mine says 115M on a fillup

    HUH?????????????????
    -Ara

    DEATH TO GARAGE QUEENS

    Comment


    • #3
      The fuel gauge and range function on M3s will never be too terribly accurate just as a limitation of the sending unit in the tank.

      The OBC on my 325is is very accurate because it has the newer style dual-sending unit that's less jumpy.

      Comment


      • #4
        Originally posted by AdamF 88iS
        The fuel gauge and range function on M3s will never be too terribly accurate just as a limitation of the sending unit in the tank.

        The OBC on my 325is is very accurate because it has the newer style dual-sending unit that's less jumpy.
        So I am guessing that fuel range is calculated using the injector pulse time and frequency along with miles traveled to get avg. MPG, and then using that along with the remaining fuel in the tank to get est. distance remaining right?

        Anyone have the specifics on this? I have been curious on exactly what BMW's solution was.

        Comment


        • #5
          Something like that.

          I think it uses instantanious velocity more than miles driven because with the MPG gauge on my 325 I can get it to read almost 0mpg if I floor it at low speeds, but floored on the freeway the MPG gauge won't go down as far becaue it knows that I'm covering ground at a faster rate when it calculates the instantanious MPG. If you reset the AVG on the OBC and watch it for the first few seconds when the avg is changing rapidly it reflects the numbers seen on the instantanious gauge; so it must take the speedo reading into account.

          Just my guess though, I've never seen an actual write up on it.
          Last edited by AdamF 88iS; 11-11-2003, 05:09 PM.

          Comment


          • #6
            So in order to continue my anal ways and get a more accurate reading I'm going to have to do the dual sending unit conversion. Awesome I can't wait. Isn't it great how you get all these ideas in your head and then they just sit there and wait...and nothing happens.
            "Condoms break baby, Deal with it."

            - Max Weinberg

            Comment


            • #7
              this is an old thread, but it never really got answered... and I'm looking for a fix. Is there a chip in the OBC that you can replace to make the 'Range' more accurate? I now have a 2.5L and need to update the OBC. How can I get this chip (if this is the solution)?
              sigpic

              1987 M3 - Weekend Joy Ride
              1972 2002tii - Pride and Joy
              1993 Accord - Dependable Beater
              2009 Tahoe LTZ 6.2L - The Beast
              1995 Chevy 1500 Z71 - Working Progress

              Comment


              • #8
                Barrron, as far as I know, there is no way to update this. If the ECU for the sport evo is a different ECU, then that could be a way I imagine. If so, that's probably an expensive way to make this update. Actually.. I never really noticed the " range" function as being an issue, I was more concerned that the miles per gallon is no longer correct..


                I have a 2005 Ford Expedition that has a range feature and it starts off optimistically as well, at least I don't think I will ever manage to get 485 miles on a tank of fuel with a 25 gallon tank in a vehicle that is rated 18 mpg hwy. I have gotten over 425 miles however, which I was very surprised and happy to see actually.

                Even assuming the range is dead on accurate, who is going to drive their tank down to zero gallons? I would imagine I run my vehicles lower than *most* people out there (no premature fuel pump failure fears here!) as I often ran my M3 down to where the range goes to ------ (under 9 miles remaining for those of you that fill up at a quarter tank :evilnah: ) and the fuel shown in the tank was still 5.5 liters (pressing 1 and 1000 together on the OBC will show you remaining fuel in liters).
                Last edited by M3 Adjuster; 01-15-2010, 04:03 AM.
                Mark Williams
                Dallas, TX

                Nothing says "welcome to the neighborhood" like a search... oh wait... looks like they are all gone! :rastajake:

                sigpic

                Comment


                • #9
                  M3 Adjuster, not the news I was hoping for, but thank you for the info! You are right, the MPG is also an issue. I never knew you could check the remaining fuel amount... will have to try it out. Sure wish there was a way to correct the accuracy of the OBC though...
                  sigpic

                  1987 M3 - Weekend Joy Ride
                  1972 2002tii - Pride and Joy
                  1993 Accord - Dependable Beater
                  2009 Tahoe LTZ 6.2L - The Beast
                  1995 Chevy 1500 Z71 - Working Progress

                  Comment


                  • #10
                    Originally posted by BarronTG View Post
                    M3 Adjuster, not the news I was hoping for, but thank you for the info! You are right, the MPG is also an issue. I never knew you could check the remaining fuel amount... will have to try it out. Sure wish there was a way to correct the accuracy of the OBC though...
                    It's a 20 years+ old car for crying out loud! What do you expect? Back then nobody else had a feature like this.Stop comparing it to modern cars.
                    In the past we just KNEW buy doing some math in our heads and and buy looking at the fuel gauge how far we can travel. (....and if in doubt a jerry can works wonders )


                    Goodbye M3, you served me well.

                    Comment


                    • #11
                      Originally posted by BarronTG View Post
                      M3 Adjuster, not the news I was hoping for, but thank you for the info! You are right, the MPG is also an issue. I never knew you could check the remaining fuel amount... will have to try it out. Sure wish there was a way to correct the accuracy of the OBC though...
                      There is a guy on R3v, "Hoveringuy" who I believe, makes signal conditioners for fuel consumption in swap cars. Check the engine swap section on that site.

                      m

                      Comment


                      • #12
                        With normal driving my 2.5L M3 now gets 300 miles per tank
                        before E light comes up

                        But, why look the MPG?

                        I preffer looking at the revs [peace]
                        '88 Sep 03,87 Zinno/Natur 2.5L--the queen
                        '90 White/Natur 2.3L---the weekend
                        '14 GT-R Red/Black ohhh..yeah!!!
                        '09 E82 135i Crimson Red/ Black w/M-Tech goodies--sold
                        '94 11/93 AW III 525i M50/S50 cams/5 speed swap--sold
                        '11 Nissan Rogue White/Gray
                        '89 Wrangler 4.2L 4x4 5 speed
                        '66 VW Beetle

                        Comment


                        • #13
                          Originally posted by theoakwoody View Post
                          OK I know it's irrevelant but I've always wondered about this. How can you make the range function more accurate. When I fill up it claims I'm going to get like 438+ miles. Yeah well I get about half that so is there anything I can do or is this just 80's technology at its finest.
                          if you push the "1" and "1000" buttons on the bottom of the obc at the same time, it will display instantaneous gas volume in liters. it is razor sharp accurate. at times i leave that on. right after you push the 1 and 1000 at the same time, go back to the range button and when you press it now it will be instantaneous and update with the correct, lower number.
                          the winningest racecar ever.

                          Comment


                          • #14
                            Originally posted by evans61 View Post
                            if you push the "1" and "1000" buttons on the bottom of the obc at the same time, it will display instantaneous gas volume in liters. it is razor sharp accurate. at times i leave that on. right after you push the 1 and 1000 at the same time, go back to the range button and when you press it now it will be instantaneous and update with the correct, lower number.
                            Really?? Once I get her back on the road (which will be months from now), I'll try this trick out. Does the update keep, or only stay accurate until the car is turned off?
                            sigpic

                            1987 M3 - Weekend Joy Ride
                            1972 2002tii - Pride and Joy
                            1993 Accord - Dependable Beater
                            2009 Tahoe LTZ 6.2L - The Beast
                            1995 Chevy 1500 Z71 - Working Progress

                            Comment


                            • #15
                              until car is shut off. then, just do it again. anytime you want a razor sharp accurate range, just hit range (display will be like 325), then push in the 1 and 1000 at the same time (display will be totally honest volume in liters), then hit the range button (display will be like 255). it really trues it up. i use it all the time like that and it never lets me down.
                              the winningest racecar ever.

                              Comment

                              Working...
                              X