» Site Navigation | | » Recent Threads | | | 1999 M3 Swap 09-07-2023 10:10 PM 06-01-2024 03:04 PM 7 Replies, 409,853 Views | | My 318ti build 05-21-2024 04:48 PM 05-28-2024 06:42 PM 1 Replies, 3,645 Views | | OMG!OMG! 05-28-2024 08:53 AM 05-28-2024 08:53 AM 0 Replies, 1,461 Views | | | | | 12-16-2006, 03:25 AM | #1 | Senior Member Join Date: Aug 2006 Location: Central NJ Posts: 2,440 | Speedometer running high I've GPS synced my speedometer and it turns out that the speedo reads exactly 2.8 mph fast at all speeds. Otherwise it's spot on. The OBC if I zero the "avg speed" mode gives me the right speed too. Anyone know how to fix this? I have no idea where the speedo and OBC get their information from. It's a constant though, and it's throwing off my gas mileage numbers I think. I always read high. | | | 12-16-2006, 04:26 AM | #2 | Senior Member Join Date: Jun 2003 Location: Greenville, SC Posts: 9,356 | They all do that. It's normal. __________________ ...steven BMW CCA #146825 1996 BMW 328ti 2003 MINI Cooper S 2016 M235i www.bmwcca.org | | | 12-16-2006, 04:39 AM | #3 | Senior Member Join Date: Aug 2006 Location: Central NJ Posts: 2,440 | Could I add a resistor to the sensor or something? I have no idea how the speed sending unit (in the diff, I think) works. | | | 12-16-2006, 09:02 AM | #4 | Senior Member Join Date: Nov 2004 Location: Bremerhaven, Germany Posts: 977 | The speed sender signal is digital so tweeking its resistance wouldn't help. You could try a digital speedometer recalibrater like those from Dakato Digital, but that would only be exact at one speed, and would under- and over-compensate at lesser and greater speeds. It would also affect the odometer. Perhaps the easiest fix for a constant 2.8 mph offset would be to disassemble the instrument cluster and bend back the needle. I believe Ron Stygar did that to correct his Z3's much more optimistic cluster. | | | 12-16-2006, 12:07 PM | #5 | Senior Member Join Date: Aug 2006 Location: Central NJ Posts: 2,440 | Thanks for the advice. I think I'll leave it alone, I compensate for it on the fly (3mph isn't too hard to add haha). The only annoying thing was the calculation of the gas mileage that I was worried about. Thanks for the advice, but it looks either to difficult or costly to do. | | | 12-16-2006, 12:33 PM | #6 | Senior Member Join Date: Nov 2004 Location: Bremerhaven, Germany Posts: 977 | The average fuel consumption calculations are often off, anyway, because of other factors. Your OBC's big, 18-button brother accepts a correction factor to make its calculations more accurate. I should correct mine, as it is about 5% too optimistic compared to the consumption I calculate from my vehicle log. Perhaps yours accepts a factor as well. In any case, the speed error experienced by the OBC should be the same as what you see in the odometer. | | | 12-16-2006, 12:35 PM | #7 | Senior Member Join Date: Aug 2006 Location: Central NJ Posts: 2,440 | Mine's about 19% off... haha. | | | 12-16-2006, 12:42 PM | #8 | Senior Member Join Date: Nov 2004 Location: Bremerhaven, Germany Posts: 977 | 19% happens to be what German VAT rises to next month. I consider that an error. | | | 12-16-2006, 03:36 PM | #9 | Senior Member Join Date: Nov 2004 Location: Lincoln Park Capitol Hill, Washington DC Posts: 741 | tire size? Pnosker.....most times it depends on the tire size. I wear a slightly off tire size with my K style OEM 16" rims: 225 45 16 and the speedo runs app. about 2.7-3.2 mph off. Had a different issue when using 225 45 17, the speedo ran 1.5-2.2 slower than actual speed. Try using this: http://1010tires.com/TireSizeCalculator.asp __________________ It's always a great day to be underwater and play with the fish.....preserve our oceans and reefs" Fariz 1997 318ti, Hellrot (Bright Red), Dinan Stage 2 Chip 16x7 OEM sport Wheels/X-Brace/Custom Strut Brace/Cold Air Intake/M-Tec Steering Wheel/Koni Adjustable FrontShocks/ Bilstein Sport Rear Shocks /H&R Sport Springs/Custom fabricated strut tower brace/Rear Strut brace, Stromung Exhaust Future Mods: E46 17" wheels or Kosei K-1 17x8.5s | | | 12-16-2006, 04:08 PM | #10 | Senior Member Join Date: Aug 2006 Location: Central NJ Posts: 2,440 | I'm running on the standard steelie tire spec. 185/65/R15 I had error with 205/60/R15s too on my alloys. It wasn't quite the same, but it's not tire size that's screwing it up. | | | 08-08-2007, 02:05 AM | #11 | Senior Member Join Date: Sep 2004 Location: Manassas, VA Posts: 4,129 | My average speed on my OBC seems off. I have driven to work on the highway at upwards of 75MPH and so far the MPH display never has gotten over 25MPH. Could this be because it is not getting it's reading from the speedo guage? I was told by the BMW mechanic that my Cruise Control won't work, until my guage cluster can be read by the Cruise Control computer. Maybe that is a sign that the speed sensor signal from the speedo really isn't operating. If it was, both OBC and C.C. would have the signals they need. Quote: Originally Posted by John Firestone In any case, the speed error experienced by the OBC should be the same as what you see in the odometer. | __________________ 1998 (July) 318ti, 5-spd OEM Armrest Blaupunkt Heidelberg CD50 CD Player/Compact Drive MP3 Player Diamond Audio 5.25" rear speakers Navman ICN 530 GPS BMWALARM.COM (with comfort settings) after market alarm system Magnecor 8.5mm wires M-Z3 Shifter/Momo Knob Burlwood Dashboard Stromung Exhaust X-brace Racing Dynamics Front Strut Bar Carbonio C.A.I. 17" Rial Rims Vader Seats/Heated/Lumbar Support M-tech Steering Wheel/Front Sway Bar/Front & Rear Bumper Depos/w 6500K Angel Eyes/6000K HIDs Clear Corners M3 Mirrors UUC Light Weight Flywheel/M5 Clutch/M3 Clutch Slave E28 3.46 LSD/Mcoupe Cover/E30 Flanges & Halfshafts UUC S.S. Brake/Clutch Lines Hartge Roof Spoiler BavAuto Springs Bilstein Sport Struts/Shocks E46 M3 Rear Shock Mounts SPC Front Camber Kit Reiger Hatch Spoiler BavAuto Rear Camber Kit Dinan Stage II Software Turner Rear Sway Bar Reinforcements BMW E46 Auto dimming mirror with Clown Nose alarm Engine Compartment Light Heated Wiper Fluid Retrofit OEM Fire Extinguisher Da'lan Trailer Hitch Rear Sun Shade OEM Fog Light Retrofit H & R MZ3 Rear Sway Bar/ UUC Adjustable End Links Cruise Control Retrofit On Board Computer Retrofit M3 twistie style side skirts Carbon Fiber Hood | | | 08-08-2007, 02:30 AM | #12 | Senior Member Join Date: Nov 2006 Location: Stamford, CT <-> Boston, MA Posts: 1,393 | L8, You could always try resetting the MPH Avg while on the highway. Press the stalk to the MPH screen, then press S/R to reset it. Then test away. __________________ BMWCCA #403399 2012 Mini Cooper S Clubman, 6-Speed Loaded 2001 325xi, Winter Package, 5-Speed Traded 1998 318ti, Active, Automatic, TOTAL LOSS R.I.P. 10/20/08 Bilstein Sport Shocks/Struts . H&R Sport Springs . Strut Reinforcement Plates . RSM Reinforcement Plates . Fogg Airbox . X-Brace . Bosal Brospeed Catback | | | 08-08-2007, 04:48 PM | #13 | Senior Member Join Date: Sep 2004 Location: Manassas, VA Posts: 4,129 | DUH......, that was easy enough. Why didn't I think of that? I reset the MPH, and it works. Well, it is an average value, so I wouldn't swear by it. I also did something very interesting today, I actually opened my Bentley manual and read it. Hopefully, armed with some wiring charts, I can sort out the Fog Light issue, and maybe the Cruise Control. Quote: Originally Posted by ATF L8, You could always try resetting the MPH Avg while on the highway. Press the stalk to the MPH screen, then press S/R to reset it. Then test away. | __________________ 1998 (July) 318ti, 5-spd OEM Armrest Blaupunkt Heidelberg CD50 CD Player/Compact Drive MP3 Player Diamond Audio 5.25" rear speakers Navman ICN 530 GPS BMWALARM.COM (with comfort settings) after market alarm system Magnecor 8.5mm wires M-Z3 Shifter/Momo Knob Burlwood Dashboard Stromung Exhaust X-brace Racing Dynamics Front Strut Bar Carbonio C.A.I. 17" Rial Rims Vader Seats/Heated/Lumbar Support M-tech Steering Wheel/Front Sway Bar/Front & Rear Bumper Depos/w 6500K Angel Eyes/6000K HIDs Clear Corners M3 Mirrors UUC Light Weight Flywheel/M5 Clutch/M3 Clutch Slave E28 3.46 LSD/Mcoupe Cover/E30 Flanges & Halfshafts UUC S.S. Brake/Clutch Lines Hartge Roof Spoiler BavAuto Springs Bilstein Sport Struts/Shocks E46 M3 Rear Shock Mounts SPC Front Camber Kit Reiger Hatch Spoiler BavAuto Rear Camber Kit Dinan Stage II Software Turner Rear Sway Bar Reinforcements BMW E46 Auto dimming mirror with Clown Nose alarm Engine Compartment Light Heated Wiper Fluid Retrofit OEM Fire Extinguisher Da'lan Trailer Hitch Rear Sun Shade OEM Fog Light Retrofit H & R MZ3 Rear Sway Bar/ UUC Adjustable End Links Cruise Control Retrofit On Board Computer Retrofit M3 twistie style side skirts Carbon Fiber Hood | | | | Currently Active Users Viewing This Thread: 1 (0 members and 1 guests) | | Posting Rules | You may not post new threads You may not post replies You may not post attachments You may not edit your posts HTML code is Off | | | |