Speedometer reading 10% too fast

[richard_sittingbull]

Hello all,
I have a 2007 NRV Dolphin LX on a W24 chassis. It is still under warranty. Workhorse indicates that my chassis came with the 22.5 wheels that are on the MH. So no new tires have been put on. The speedometer reads 70mph when my GPS and my 2008 Honda CRV say I'm going 63 mph. The difference is exactly 10% off. This is also verified by the highway speedometer checks in the 3 states that I just drove through. They say 5 miles have past and my speedometer indicates 5.5 miles.
My problem is that the Workhorse factory dealer says that his instruments are saying all is OK. I have an appointment with him on Monday at 10:00am to go over his findings. Is anyone out there that has had this problem and can enlighten both me and the mechanic? I'd sure appreciate any help that you can provide.

[richard_sittingbull]

Hello all,
I have a 2007 NRV Dolphin LX on a W24 chassis. It is still under warranty. Workhorse indicates that my chassis came with the 22.5 wheels that are on the MH. So no new tires have been put on. The speedometer reads 70mph when my GPS and my 2008 Honda CRV say I'm going 63 mph. The difference is exactly 10% off. This is also verified by the highway speedometer checks in the 3 states that I just drove through. They say 5 miles have past and my speedometer indicates 5.5 miles.
My problem is that the Workhorse factory dealer says that his instruments are saying all is OK. I have an appointment with him on Monday at 10:00am to go over his findings. Is anyone out there that has had this problem and can enlighten both me and the mechanic? I'd sure appreciate any help that you can provide.

[Bill Davis]

Added a shortcut to MH - Problems, Solutions, and After Market Forum for better visability. Your post will also remain here.

[paz]

A Workhorse service center with the proper equipment should be able to reprogram the computer to correct the speedometer error. I found mine is off a little less than 2%, which is close enough for me; but 10% is a little too much.

There has been some discussion of this problem over on the Workhorse Forum. If you don't get any satisfaction from Workhorse, try contacting Brazel's RV or Redlands Truck. Even though you may not be close to either one of these companies, you will probably be able to ship your module to them to reprogram.

[Ceratto's Grotto]

I was told by the dealer of my Mini Cooper that they (cars) are allowed (via whatever laws and/or rules apply) 5 MPH over / under in the adjustment of a speedometer.

[newk72]

This was my previous post.

The story begins with a trip to Florida to pick up our 2008 Dolphin LX. Leaving the dealership on the Interstate I set the cruise on 70 mph. Soon everything on the road is flying by me. Next the computer shows I am averaging 11.5 mpg. I thought boy the new Allison is really something. With everything on the road still flying by, I ask my wife what speed the gps shows. Just ove 62 mph she replies. Then we check the odometer against the gps, the mileage is off by 10%. Returning to Texas I go to the Workhorse shop. It would take half a day to tell all of the attempts to reprogram working with both Workhorse and GM. After numerous downloads to update the programmers and the use of three different programmers it was decided to send the ecm to GM. No luck after two days of attempts to recalibrate. Turns out there is a glitch in the program that will not let them in to recalibrate the speedometer. The solution was to build a new computer with the correct tire size. Everything works fine now. They told me if you change tires, be absolutely sure you replace with EXACTLY the same diameter tire, as we cannot recalibrate. Another issue was the milage showing 10% excess. At 8000 actual miles I am showing 8800. I am sure Workhorse will be fair with me as they have done all they could do. This is something to think of if you are planning to change tires.

Marshall & Barbara
Cairn Terror Bonnie
2008 Dolphin LX 6367
2004 Saturn Vue
Abilene, Tx

[cannon man]

same problems with our 07 LX. speedo is about 8mph fast at 60 mph. also mpg readout is way high under light load. like 15 to 30 mpg. how i wish it were true. only 3K miles on rig so i hope its a easy fix. took it in last friday. hoping for the best.

[DriVer]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by cannon man:
same problems with our 07 LX. speedo is about 8mph fast at 60 mph. </div></BLOCKQUOTE>The guys at Brazel's RV Performance can actually fix this problem. Give them a call if you are not satisfied.

[richard_sittingbull]

Thank you to everyone who has offered to lend a hand in my quest to have this speedometer read correctly. If Workhorse is unrelenting in indicating that they have a problem, I will contact Brazel's RV Performance as suggested.
I was unable to find pertinent information on the Workhorse site but I will retry again now that it has been mentioned that they have covered it there.
Once again, thank you. These forums are great because of all the people who make the effort to respond to queries when appropriate as well as to the all important moderators.

[newk72]

You should not have to go to anyone but Workhorse. They or GM installed the wrong computer for the tire size. My problem was completely covered by warranty. Hold there feet to the fire and make them do the right thing. They know they have this problem and they should fix it.

[dieselclacker]

richard_sittingbull, Just think, you are getting 10% better mileage on your Workhorse!

Dieselclacker

[paz]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by newk72:
You should not have to go to anyone but Workhorse. </div></BLOCKQUOTE>
Both Brazels RV and Redlands Truck ARE authorized Workhorse service centers. The ones who say they can't fix the problem either don't know what they are doing or don't have the equipment to reprogram the module to correct the speedometer error and they are hoping the problem will go away.

[Jo/Lee]

Tire sizes and rear gear ratios ARE programable in GM computers.All you need is the proper equipment and someone that knows what they are doing. Not an easy task these days.

Lee