Sprinter-Forum    
 

Go Back   Sprinter-Forum > Regional Discussions > Canada


 
Thread Tools Display Modes
Old 12-30-2010, 10:29 PM   #11
autostaretx
Erratic Member
 
autostaretx's Avatar
 
Join Date: Sep 2006
Location: Seattle
Posts: 15,631
Thanks: 2,704
Thanked 6,790 Times in 4,995 Posts
Default Re: Speedometer accuracy

Quote:
(Does anyone know the formula used by MB?)
Know? No... but i can guess it.
The ECU knows the fuel rail pressure, the injector orifice size and the duration of a squirt.
From that you can work out the volume of fuel delivered per squirt.
After that it's volume * number of squirts per mile.

The ScanGauge (and other OBD-II devices) don't have all of the background data, but it does get some "fuel delivered" data in unknown (to me) units (let's call it milliliters).
To calibrate the ScanGauge, you tell it how "wrong" it was in estimating "fuel consumed" each time you fill the tank.
That lets it back-figure how much to fudge the "milliliters" to achieve a somewhat accurate "unit", and then it applies it to the miles driven.

How either of them handles the "stopped at traffic light" and "idling" situations is beyond me.
They could (reasonably) ignore that in its MPG (l/km) calculations... yes, it's "fuel consumed", but it's not "miles travelling".

--dick
p.s. my speedometer reads 3% high, the odometer is accurate, the ScanGauge reports accurate MPH.
(compared with "check your speedometer" highways and GPS)
__________________
2005 T1N 118" Freightliner 2500 Passenger Wagon (2.7L, 15" tires, standard (short) roof)
Get YOUR Sprinter's full configuration datacard by entering your VIN to https://www.datamb.com/
http://diysprinter.co.uk/reference <-- lots of service documentation, Thanks to Jens Moller and Arnie_Oli
((as always: this post may go through a couple of post-posting edits... so maybe give it ten minutes before commenting))

Last edited by autostaretx; 12-30-2010 at 10:31 PM.
autostaretx is offline   Reply With Quote
Old 03-15-2011, 02:41 AM   #12
brassarl
2006 T1N 2500 Long & Tall
 
Join Date: Mar 2011
Posts: 214
Thanks: 370
Thanked 72 Times in 48 Posts
Default Re: Speedometer accuracy

Quote:
Originally Posted by jpseyer View Post
I just receive my new 2010 Sprinter and I notice when I drive at 100 km/h according to my GPS the van speedometer is indicating 105 km/h. It is 5% error on a brand new vehicule with original tire. My question is, is it normal or do I have something wrong on my Sprinter?
If I remember correctly there was a big uproar in Canada on this some years ago, remember you potentially lose 5% of your warranty also
Lou
brassarl is offline   Reply With Quote
Old 03-15-2011, 06:26 PM   #13
autostaretx
Erratic Member
 
autostaretx's Avatar
 
Join Date: Sep 2006
Location: Seattle
Posts: 15,631
Thanks: 2,704
Thanked 6,790 Times in 4,995 Posts
Default Re: Speedometer accuracy

Quote:
Originally Posted by brassari
remember you potentially lose 5% of your warranty also
As earlier postings report, the *odometer* (hence: warranty duration) is accurate.
Only the MPH / KPH over-reports.

On the T1N model with 15" wheels... when people install 16" (without informing the ECU), the speedometer becomes accurate, and the odometer then *under*reports.
Hence your warranty lasts longer (or at least "further").

--dick
__________________
2005 T1N 118" Freightliner 2500 Passenger Wagon (2.7L, 15" tires, standard (short) roof)
Get YOUR Sprinter's full configuration datacard by entering your VIN to https://www.datamb.com/
http://diysprinter.co.uk/reference <-- lots of service documentation, Thanks to Jens Moller and Arnie_Oli
((as always: this post may go through a couple of post-posting edits... so maybe give it ten minutes before commenting))
autostaretx is offline   Reply With Quote
Old 08-26-2012, 09:23 PM   #14
peterinter
 
Join Date: Aug 2012
Location: Vancouver B.C.
Posts: 2
Thanks: 1
Thanked 0 Times in 0 Posts
Default Re: Speedometer accuracy

love my gps ...except when it lies
peterinter is offline   Reply With Quote
Old 09-08-2012, 04:55 PM   #15
JonesOnHomes
Guest
 
Posts: n/a
Default Re: Speedometer accuracy

Quote:
Originally Posted by jpseyer View Post
I just receive my new 2010 Sprinter and I notice when I drive at 100 km/h according to my GPS the van speedometer is indicating 105 km/h. It is 5% error on a brand new vehicule with original tire. My question is, is it normal or do I have something wrong on my Sprinter?
I don't care what anyone says about this being intentional for legal speed limit reasons, we live in a time when technology is far advanced from the old days. If you can't make it right, don't make it at all! 5% deviation on accuracy is not even the case. If I am driving at 50km/h, the readout is 45. That is a difference of closer to 10% out. So if the rule is a 5% deviation allowed, it is a defect. The fact is that this is more like a CCM bicycle with a Mercedes Logo on it, I am appalled!
  Reply With Quote
Old 09-24-2012, 12:53 AM   #16
JustDisGuy
 
Join Date: Apr 2009
Posts: 12
Thanks: 4
Thanked 1 Time in 1 Post
Default Re: Speedometer accuracy

I figure mine is out damn near 10% high, too. So when the electronic limiter stops me from accelerating past 130 kph, I'm actually going less than 120. Makes passing in a 110kph zone interesting...

Anyone know how to adjust either the speedo or the limiter?
JustDisGuy is offline   Reply With Quote
Old 10-27-2012, 12:33 AM   #17
steve604
 
Join Date: Oct 2012
Posts: 43
Thanks: 0
Thanked 10 Times in 6 Posts
Default Re: Speedometer accuracy

mine seems to be 5km/h fast no matter what speed i'm actually doing. 100=105 and 30=35 on the speedo.
steve604 is offline   Reply With Quote
Old 08-27-2013, 12:32 PM   #18
slapac
 
Join Date: Jun 2011
Posts: 2
Thanks: 7
Thanked 0 Times in 0 Posts
Default Re: Speedometer accuracy

Geting close on the street to the radar stand check your speed then Look at the radar,. They match perfect
slapac is offline   Reply With Quote
Old 08-27-2013, 02:55 PM   #19
Aqua Puttana
Poly - Thread Finder
 
Aqua Puttana's Avatar
 
Join Date: Apr 2008
Location: The Falls of Niagara, USA
Posts: 23,066
Thanks: 11,575
Thanked 12,707 Times in 8,076 Posts
Default Re: Speedometer accuracy

Quote:
Originally Posted by slapac View Post
Getting close on the street to the radar stand check your speed then Look at the radar,. They match perfectly
As was mentioned, that can depend upon tire and rim size as compared to OEM. Typically when a stock T1N Sprinter speedometer reading is compared to a GPS or radar reading the speedometer will be about 3 mph high as to the other sources. I agree that the odometer is accurate as to some of the milepost interval readings (much further than just one mile) I've compared to while bored over some long trips.

vic
__________________
DAD NAS (N. Amer. Spec) 2004 140 2500 >326,000+ mi. Arctic Whitewash Brush-tone Grey
2006 Freightliner 140 2500HC >172,000+ mi. Arctic Whitewash (Spotted Snow Leopard accents)
"My opinion and worth everything you'll never pay for it." assumed.
Anyone can hold the helm when the sea is calm. Publilius Syrus
"There are only 10 types of people in the world: Those who understand binary, and those who don't." HaWiiLuVeR
16 ounces of unnecessary prevention can be worth a pound of manure.

Last edited by Aqua Puttana; 08-27-2013 at 04:02 PM.
Aqua Puttana is offline   Reply With Quote
Old 08-27-2013, 03:59 PM   #20
chromisdesigns
 
Join Date: Feb 2013
Location: Monterey peninsula
Posts: 1,790
Thanks: 204
Thanked 564 Times in 430 Posts
Default Re: Speedometer accuracy

Having owned various BMWs for years, I figured the Sprinter was going to be the same deal -- speedo reads high. However, I was delighted to find it's spot on -- agrees with my GPS and street radar signs to within 1 mph. This is a 2013 chassis.

The whole "speedo reads fast" issue is a perennial in BMW forums -- comes back all the time like a weed!

I don't know how Mercedes handles the speedo / odo issue, but in a BMW, the odometer is correct, and the displayed speedometer reading is jiggered electronically to make it read high. So you don't "lose part of your warranty". Typically the speedo reads 5% high. In fact, on a BMW (with the right tool) you can code the computer so that the digital speedo reading is correct, but the analog speedo is not fixable. I suspect Mercedes does the same thing.

Funny part is, it's common to hear people who switched from Mercedes to BMW complaining "My old Mercedes didn't do this!"...
__________________
2014 Coach House Platinum II
on 2013 Mercedes chassis
Soon to be up for sale due to repeated Mercedes diesel bugs!

If you are still into sprinter rvs and think you might want the nicest possible version send me a PM for details.
chromisdesigns is offline   Reply With Quote

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump



All times are GMT. The time now is 11:31 PM.


Powered by vBulletin® Version 3.8.9
Copyright ©2000 - 2019, vBulletin Solutions, Inc.