wrong speed and mileage...

[davidlizard]

Hey guys, I think the speedometer of my car is wrong by 9-10% and I know it because the speed on the car speedo is not the same that is on my GPS. I tried 2 different GPS and the gap is still there. I think it also change my car mileage... My car is a 04 USP stock except sofware...

[NVR STSFD]

Seems mine is off a little also. Went by a digital speed sign and it was off by 3-4 mph. Called my wife who was following me and we were off by the same amount. Sorry I don't have any info for you but hopefully somebody can help us out.

[LateApex]

I'll try it with my GPS tomorrow for more input. Mine is stock so maybe it will show if the software you have is doing it. It's probably just that the GPS takes a second to update and the speed sign is innacurate but it's interesting to me to know for sure.

[sean1.8t]

all stock tires sizes eh?

usually the speedo and GPS speed on every car is off. especially at higher speeds like 100+mph. and it's usually in the 10% range iirc.. so im not sure if it's a constant 10% all the way through. or if it's a static percentage difference(which i would think i would be)..

either way. i have no idea, but i hope that helps a little bit

[davidlizard]

Yes I have stock tire and rims, and I think it's a static % difference... and I also notice a difference between the speedometer and the car computer that says the average speed... I drive on cruse control @ 100km/h on my speedo for a while and the car's computer indicates an average speed of 93 km/h.... I'm canadian, that why I talk in Km/h ...

[mxrz]

Yes I have stock tire and rims, and I think it's a static % difference... and I also notice a difference between the speedometer and the car computer that says the average speed... I drive on cruse control @ 100km/h on my speedo for a while and the car's computer indicates an average speed of 93 km/h.... I'm canadian, that why I talk in Km/h ...

That isn't right, normally, when the speedo shows 100, you should be doing about 97-98. 93 seems just a bit too off from the norm, I would have that checked out, if your tires really are the right size and properly inflated.

[infernocl]

it is a common problem, i think all B6s read ~7% high

[bavaria75]

All German cars read higher MPH or KMH due to the german TUV law. What says the car can show higher speed but not lower speeds. However 10% lower is to low. Usually they go ahead 5 KMH.
By the way, most Amarican cars are made dead on and very accurate.

[wifeysaudi]

doesnt that affect how many miles your car has on the odometer in the long run. Just curious because honda been sued for something similar on the civic. At times it feels like I gain more miles then I should.

http://www.cbsnews.com/stories/2007/...n2562144.shtml

[davidlizard]

Yes! Exactly!, Last summer I've compared the GPS odo and mine between Boston and Hampton beach and the difference was the same 9-10% than my sppedo whit the speed, So, the car has less milleage than the odometer shows... I think this sucks because the value of the car is lower whit this mileage... Does somebody know if the dealership can adjust this?

[davidlizard]

Faster odo and speedo cause: better MPG consumption, better 0-60, shorter warranty coverage, better lease extra charges, and a lot of million $ in compagnies pocket. Also our resale value is decrease... In think I'll pay my mecanic to down my mileage to correct and reallistic one before sale my car in the future...

[B-Rob]

Faster odo and speedo cause: better MPG consumption, better 0-60, shorter warranty coverage, better lease extra charges, and a lot of million $ in compagnies pocket. Also our resale value is decrease... In think I'll pay my mecanic to down my mileage to correct and reallistic one before sale my car in the future...

MPG and 0-60 times are both determined by road tests with diagnostic equipment, no car's internal speedo/odo accurate enough to be used for that stuff.

And it's illegal to both roll back the mileage on a car and to knowingly sell a car whose mileage has been rolled back, even for perceived "correction" purposes, so good luck finding a mechanic to do that for you. It's morons like you who make people so wary of buying a used car in the first place.

[dirtybrd]

All cars read a little high. This is just to keep your mind thinking you're speeding. Kinda of like when you set your alarm clock 20 mins. fast, you know it is fast but it still makes you think you're late. But it is definitely not a "Let's screw the car owner, or shorten the warranty".

[wifeysaudi]

all cars don't read high my 04TL 04armada 03g35 all read correctly and was exact as my gps not even 1mph off, just my a4 does not read correctly. Also some car makers have already been sued for this issue.

[B6 Dude]

Speedos, especially analog ones, have tolerances that vary the measurement from one car to another. Things like tire pressure or specific brand of tire can also introduce small errors in the speed measurement. This is one of the reasons that the manufacturer sets the speedo to show a bit higher, so they don't get sued if you get a ticket for doing 71 when the speedo shows 70.

The different speed on the indicator/pointer doesn't necessarily correspond to a matching difference in odometer reading. If they don't match, you can sometimes tap the pointer a bit to let it "slip" on the shaft to adjust the pointer. If not, perhaps you can pull off the pointer and re-position it. But all disclaimers apply here, so don't blame me if you don't do this correctly.

If your pointer and odometer are off by a similar amount, you'll need to look to tire sizes, tire pressure, or some type of speedo re-calibration device. For a few mph off I wouldn't worry, but to each their own.

[gtimart]

I don't think you car's total mileage will be wrong. It's just the arrow that shows higher. Reset your trip computer on the highway and check your average speed. That number will be closer to reality. On my car, when the arrow indicates 123kph the trip reads 118kph.