Is it me or my speedo is weird...

[Logzy]

VAG-COM have already come back to me, their response is;

"It sounds like the inaccuracy is programmed into the flash memory of the instrument cluster. Flashing is not something that can be done with VAG-COM"

Know knowing this I wonder if theres any software engineers out there that could hack and reflash the memory in the instrument cluster.

My initial thoughts are a tuner although i doubt it as its the memory in the instrument cluster and not the ECU.
My second thought is a specialsed speedometer repairer / electronics engineer similar to those that shouldnt but do wind back a digital odometer reading.

[Logzy]

I'm on a mission.

See this.

Does anyone have a wiring diagram for the inputs to the instrument cluster.
I want to work out if this would be suitable and what the signal from the ECU to the cluster is.

There is also a product called Speedohealer.
I have sent them an email regarding the 2007-2007 Mk5 VW Golf.

[Splashalot]

I'm on a mission.

See this.

.

Good work.

However, I'm wondering if it in our case it is an error with the electronic signal, or if the physical speedo guage is partly to blame - perhaps through incorrectly marked figures?

Never the less, looks like a good fix.


SS

[GermanwithaVdub]

just white out the speeds on the speedo and write in the correct ones

[VW Convert]

just white out the speeds on the speedo and write in the correct ones

That's what I call lateral thinking.....I like it!

Cheers

George

[Splashalot]

just white out the speeds on the speedo and write in the correct ones

Good one Edward (De Bono)!

[DaveMack]

Or ... twist the speedo 9% of it's circumference to the right.

Dave

[Logzy]

I'm even closer to finding a soultion to the speedo problem now.
With the wiring diagrams i have identified the speed input wire into the instrument cluster.

Now i just need my new car so i can measure the input and fix the problem.
3 months to go.

[99gti]

A few things to consider.

Is it out by x amount of k/m's or is it out by x percentage.

If it's out by x km's, then advancing the spring should keep it accurate through it's range.

If it's out by x percentage, then you would most likely have to decrease the resitance so as the the current sent is greater in order to advance the needle at a constant percentage. You would first need to determine what voltage is required for the needle to reach each of the increments marked. Then using the good old v(volts)=i(current) * r(resistance) formula, map out the resistance required for each and then divide the total of all the increments to figure out what resistor you would need.

Problem solved.
v = ir

[edstergtsport]

this all getting too complicated for me, at first i made this thread cuz i thought there must be a quick fix...
I just wish VW will wake up and fix the speedo prob for all.

[Mixer]

Most new VW speedos under-read by about 7-9%. Designed that way as per TDI Dude's post.

Interestingly mine is about 15% out and VW say they can do nothing about it!

I thought the ADR was for +/- 10%?

[gregozedobe]

A few things to consider.

Is it out by x amount of k/m's or is it out by x percentage.

Another thing to consider: Is the error consistent or variable ?

If it is 5% slow at 60Kmh, 10% slow at 80Kmh but 4% slow at 110kmh then it becomes much complex to fix electronically or mechanically (back to the "white-out" solution )

Another way out would be to have a GPS unit dedicated to showing your current speed, and train yourself to look at the GPS and ignore your speedo reading.

But it is annoying to have something that you have paid for, is perfectly located, is supposed to tell you how fast you are going, but simply doesn't

[Logzy]

This is fk'n bs for a speedo to be out so much.

Surely something needs to be done about this.
Lots of letters to VWA from everyone. I dont know
I will check the ADR however i though after xxxx year they had to be more accurate.

[neil]

Finished the Climate control technique as mentioned from the start of this thread.
Had to adjust the fan knob until temperature reads 19.0 not 19.1 as mentioned.
19.1 was indicating MPH and 19.0 KMH. This may be because I have the jetta not a Golf.

Speeds as follows.
speedo / climate control
40........... 38
50........... 48
60........... 57
70........... 67
80........... 77
90........... 87
100......... 97
110......... 107

So fairly happy with the results.
These results are for the MY08 model.
Next step is to borrow a GPS to check the speed , as I have all the B-doubles on the Fwy leaving me standing still.

[Logzy]

Neil,
It will be intersting to se how those figures compare to GPS figures.
Please let us know.

If they are correct then this is good.
I only hope when i get my new Golf GT Sport in March 08 that the speedo is only 3k's out too.