VW TDI forum, Audi, Porsche, and Chevy Cruze Diesel forum banner

speedo and tach reading high

4K views 19 replies 7 participants last post by  gt4494 
#1 ·
Hi all,

I've read about moving the needle on the speedo and using vag-com to correct the error, but my tach seems to be the same. Car off, neither guage reads "0". Not even close really lol. I'm wondering if the needles should be at the zero mark on both? If so, has anyone done the tach as well? TIA!!
 
#3 ·
Yes, good point. I know that at 100km/hr on the speedo, GPS says I'm going about 92km/hr. I know that one is out, and quite sure doing the needle and vag-com fix should correct it. But the tach "seems" to read higher than others say at a given speed. I'll have to verify that with vag-com as well I guess. The tach doesn't really matter to me, I just figured that while I'm in there, might as well do both :)
 
#4 ·
since the 70s its common to read higher then you go.. gives them big win in court if your nailed speeding as you must speed to gain the tax coupon of speed.. why going with flow best...

now the thing to be cautious on.. burnt up speedo/intrument cluster is a warning sign to ground issues.. jump a ford/honda wrong.. burns stuff up like speedo/temp gauges.. your immo is part of the cluster.. burn it up your walking..
 
#9 ·
True, they don't rest at zero or below, just never noticed that before lol. Driving on the highway the first few times EVERYBODY was passing me....angrily lmao. So I confirmed with GPS that I was way under speed on the speedo. First thing I checked was tire size, then I recalled a car I had in the past, the ECU could be flashed with different tires sizes depending on what was fitted. Thus began the vw speedo investigation!!
 
#15 ·
To be sure the cluster needles are working correctly, you'll have to do an output test with vcds.

it'll put the rpm to 3000, the temp to 90, the fuel to 1/2 and the speedo to 100km/h.

This way you can be sure they are electrically working, I also use to adjust them manually with this method.
 
#16 ·
every German speedometer that I have seen reads approx 3 mph (4-5Kph ) higher than the vehicle is going. This is based on European Law and the fines levied. If the vehicles read slow the fine to the manufacturer is very high. Due to manufacturing differences it is better (easier) to make them all read slow and avoid any problems.

https://sec.theglobeandmail.com/glo...ast-as-you-think/article11487709/?service=amp

Its called European law ECE-R39

https://en.wikipedia.org/wiki/World_Forum_for_Harmonization_of_Vehicle_Regulations
 
#17 ·
Little update, I did move the needles to zero, and everything seems great. We have speed checks which display your speed as you go by, it's exact every time :) Tach is now reading "spec" at the given speeds. I have not checked with VCDS, but next time I have a chance, I'll have an output test done.
 
#19 ·
tomarrow i take my 84 coupe on its first road trip since 05... wed i drove it at 70mph for the first time since 05... i lack gps.. only borrowed others or had passengers with them... well i know this... 72mph = 3200rpm in 5th... the speedo head is so screwed up... 45mph is 55 reality... 58 is 70... it is so far off in the wrong way... i live off a 55mph speed trap.. need to find my 200km speedo head.. the 120mph ones sucked.. but 85.. LOL.. look at my pic to the left does not work either for me... i use tach in car with speedo head to left.. but the gear ratios are 100% different... only know the 3200rpm=72mph from all the trips i took it in with this trans
 
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top