Mike "Wuzzy121". Rest in peace, brother

Go Back   Tacoma World Forums > Off-Topic > General Automotive

Notices

MPG calculation wrong because speedo off?

Reply
 
Thread Tools Search this Thread
Old 04-30-2011, 05:12 AM   #1
rizzo20 [OP] rizzo20 is offline
Junior Member
rizzo20 will become famous soon enoughrizzo20 will become famous soon enough
 
rizzo20's Avatar
Joined: Apr 2011, #55026
Location: Central PA
Gender: Male
Posts: 26
rizzo20's Tacoma Gallery
MPG calculation wrong because speedo off?

My TRD Sport reports my speed 2 mph faster than I'm really traveling. (speedo says 60 when my GPS says 58). It's accurate to assume that my odometer is incorrect because of this, correct? How can I figure out my true MPG?

I haven't modified a single thing with the drive train and the speedo is wrong straight from the factory. I haven't talked to the dealer yet but shouldn't they make this right?
  Reply With Quote
Old 04-30-2011, 05:25 AM   #3
rizzo20 [OP] rizzo20 is offline
Junior Member
rizzo20 will become famous soon enoughrizzo20 will become famous soon enough
 
rizzo20's Avatar
Joined: Apr 2011, #55026
Location: Central PA
Gender: Male
Posts: 26
rizzo20's Tacoma Gallery
Does that mean the trip counter and odometer are correct?
  Reply With Quote
Old 04-30-2011, 08:07 AM   #5
Junior Member
jgraham has a spectacular aura aboutjgraham has a spectacular aura about
Joined: May 2009, #17259
Location: Greer, SC (formerly Florence)
Age: 32
Gender: Male
Posts: 29
jgraham's Tacoma Gallery
I've checked the speedo against my Scangauge and GPS. Scangauge data from the computer matches the GPS. It's the speedo needle that is off. Scangauge miles traveled have matched up to odo miles traveled and GPS miles traveled exactly as well, during trips of over 300 miles.
  Reply With Quote
Old 04-30-2011, 06:34 PM   #6
rizzo20 [OP] rizzo20 is offline
Junior Member
rizzo20 will become famous soon enoughrizzo20 will become famous soon enough
 
rizzo20's Avatar
Joined: Apr 2011, #55026
Location: Central PA
Gender: Male
Posts: 26
rizzo20's Tacoma Gallery
Thanks for the info, thats all I need to know.
  Reply With Quote
Old 04-30-2011, 06:43 PM   #7
Senior Member
slmgt is one of the sharper tools in the shedslmgt is one of the sharper tools in the shedslmgt is one of the sharper tools in the shedslmgt is one of the sharper tools in the shedslmgt is one of the sharper tools in the shedslmgt is one of the sharper tools in the shedslmgt is one of the sharper tools in the shedslmgt is one of the sharper tools in the shedslmgt is one of the sharper tools in the shedslmgt is one of the sharper tools in the shedslmgt is one of the sharper tools in the shed
Joined: Oct 2010, #44921
Location: San Francisco Bay Area
Gender: Male
Posts: 661
slmgt's Tacoma Gallery
This simple thread rocked!

Thank you OP, Brunes and jgraham. It was something I too was wondering about and with 7 posts, the answer was given with proof!
  Reply With Quote
Old 04-30-2011, 08:15 PM   #8
Junior Member
jgraham has a spectacular aura aboutjgraham has a spectacular aura about
Joined: May 2009, #17259
Location: Greer, SC (formerly Florence)
Age: 32
Gender: Male
Posts: 29
jgraham's Tacoma Gallery
You're welcome. I'm glad I could help.

I should also note that I'm running the stock Firestone Destination LE 215/70R15 tires on stock wheels.
  Reply With Quote
Old 04-30-2011, 08:18 PM   #9
Senior Member
JLink is one of the sharper tools in the shedJLink is one of the sharper tools in the shedJLink is one of the sharper tools in the shedJLink is one of the sharper tools in the shedJLink is one of the sharper tools in the shedJLink is one of the sharper tools in the shedJLink is one of the sharper tools in the shedJLink is one of the sharper tools in the shedJLink is one of the sharper tools in the shedJLink is one of the sharper tools in the shedJLink is one of the sharper tools in the shed
 
JLink's Avatar
Name: Josh
Joined: May 2010, #36795
Location: Ocean, NJ
Age: 26
Gender: Male
Posts: 9,431
JLink's Tacoma Gallery
stock tires on my trd sport were 265/65/17, I just upgraded to 265/70/17's and my speedometer is now spot on.
  Reply With Quote
Old 04-30-2011, 08:57 PM   #10
Senior Member
slmgt is one of the sharper tools in the shedslmgt is one of the sharper tools in the shedslmgt is one of the sharper tools in the shedslmgt is one of the sharper tools in the shedslmgt is one of the sharper tools in the shedslmgt is one of the sharper tools in the shedslmgt is one of the sharper tools in the shedslmgt is one of the sharper tools in the shedslmgt is one of the sharper tools in the shedslmgt is one of the sharper tools in the shedslmgt is one of the sharper tools in the shed
Joined: Oct 2010, #44921
Location: San Francisco Bay Area
Gender: Male
Posts: 661
slmgt's Tacoma Gallery
Quote:
Originally Posted by JLink View Post
stock tires on my trd sport were 265/65/17, I just upgraded to 265/70/17's and my speedometer is now spot on.
Yet another fascinating revelation. I wonder if Toyota calibrated the speedometers with 70/17s instead of a 65/17s, changed and then forgot to re-calibrate.

I think I will be switching to 70/17s as well once I see no more use out of my Hockeypucks (aka Dunlops).
  Reply With Quote
Old 04-30-2011, 09:13 PM   #11
lifer
bocna is on a distinguished road
Joined: May 2008, #6843
Location: no cal.
Gender: Male
Posts: 21
bocna's Tacoma Gallery
Quote:
Originally Posted by JLink View Post
stock tires on my trd sport were 265/65/17, I just upgraded to 265/70/17's and my speedometer is now spot on.
same here.
  Reply With Quote
Old 05-01-2011, 05:14 AM   #12
abides.
Brunes is one of the sharper tools in the shedBrunes is one of the sharper tools in the shedBrunes is one of the sharper tools in the shedBrunes is one of the sharper tools in the shedBrunes is one of the sharper tools in the shedBrunes is one of the sharper tools in the shedBrunes is one of the sharper tools in the shedBrunes is one of the sharper tools in the shedBrunes is one of the sharper tools in the shedBrunes is one of the sharper tools in the shedBrunes is one of the sharper tools in the shed
 
Brunes's Avatar
Coast Guard: LT- CG MH-65C/D Driver- CGAS NOLA
Name: Mark
Joined: May 2008, #7011
Location: Big Easy, USA
Age: 30
Gender: Dude
Posts: 17,718
Brunes's Tacoma Gallery
Send a message via AIM to Brunes
Quote:
Originally Posted by JLink View Post
stock tires on my trd sport were 265/65/17, I just upgraded to 265/70/17's and my speedometer is now spot on.
Which means you need to look at the computer outputs. Cause the discrepancy at the speedo needle comes from the digital to analog conversion and is a percentage. If your needle that means the input is off (at least I think it does...)
  Reply With Quote
Old 05-01-2011, 05:38 AM   #13
Senior Member
JLink is one of the sharper tools in the shedJLink is one of the sharper tools in the shedJLink is one of the sharper tools in the shedJLink is one of the sharper tools in the shedJLink is one of the sharper tools in the shedJLink is one of the sharper tools in the shedJLink is one of the sharper tools in the shedJLink is one of the sharper tools in the shedJLink is one of the sharper tools in the shedJLink is one of the sharper tools in the shedJLink is one of the sharper tools in the shed
 
JLink's Avatar
Name: Josh
Joined: May 2010, #36795
Location: Ocean, NJ
Age: 26
Gender: Male
Posts: 9,431
JLink's Tacoma Gallery
Quote:
Originally Posted by Brunes View Post
Which means you need to look at the computer outputs. Cause the discrepancy at the speedo needle comes from the digital to analog conversion and is a percentage. If your needle that means the input is off (at least I think it does...)
I'm not sure what you are saying.. all I know is that the speedometer now agrees with the gps and the scan gauge, but before I got new tires the gps and scan gauge were the same and the truck's speedometer was off by a couple mph's
  Reply With Quote
Old 05-01-2011, 05:47 AM   #14
abides.
Brunes is one of the sharper tools in the shedBrunes is one of the sharper tools in the shedBrunes is one of the sharper tools in the shedBrunes is one of the sharper tools in the shedBrunes is one of the sharper tools in the shedBrunes is one of the sharper tools in the shedBrunes is one of the sharper tools in the shedBrunes is one of the sharper tools in the shedBrunes is one of the sharper tools in the shedBrunes is one of the sharper tools in the shedBrunes is one of the sharper tools in the shed
 
Brunes's Avatar
Coast Guard: LT- CG MH-65C/D Driver- CGAS NOLA
Name: Mark
Joined: May 2008, #7011
Location: Big Easy, USA
Age: 30
Gender: Dude
Posts: 17,718
Brunes's Tacoma Gallery
Send a message via AIM to Brunes
Quote:
Originally Posted by JLink View Post
I'm not sure what you are saying.. all I know is that the speedometer now agrees with the gps and the scan gauge, but before I got new tires the gps and scan gauge were the same and the truck's speedometer was off by a couple mph's
That was the info I'm looking for...Not the answer I expected up-but it helps.
  Reply With Quote
Reply

Thread Tools Search this Thread
Search this Thread:

Advanced Search

Similar Threads
Thread Thread Starter Forum Replies Last Post
ScanGauge: Confused-is my mpg actually calculated and my speedo gauge is off? Airwolf NSX Off-Topic Discussion 4 02-11-2012 09:02 PM
New MPG personal best, 25.1 MPG! kogary 2nd Gen. Tacomas 12 07-11-2011 08:55 AM
Speedo is off!! stack676 4 Cylinder 8 05-03-2011 07:54 AM
Do I have the wrong wheel and tire size on my 01 Prerunner or was Midas wrong? prerunnerSD Wheels & Tires 4 02-16-2010 05:13 PM
Wrong Gear Oil???? Lower MPG's after change... kingston73 Technical Chat 11 01-31-2010 11:22 AM


Copyright © 2014 Tacoma Forum. Tacoma World is not owned by, or affiliated with Toyota Motor Corporation.