Dash inaccurate

[Popeye]

OBS 98 Tahoe running 285/70/16, stock everything else.

I have a inaccurate dash where the tach shows 10% more than it should. Verified via OBDII scanner. The speedometer shows 144km/hr when i am at 100km/hr. Verified via GPS. All other guages are accurate from what i can see. The trip and total km guages are accurate, again verified via GPS.

As an interim solution i bought a old GPS to watch my speed. I have contemplated in getting a ScanGuage II and be done with it.

I am reluctant to change the complete dash as it would change the total km reading. Would someone have an idea where this discrepancy comes from? The OBD scanner shows that the computer is reading correct from the sensors.

Any advise is apreciated. thx in advance.

 

[scottg918514]

Are your tach and speedo needles zero'd out when the vechile is off? If not, pull cluster, fairly easy to take apart. Pull needles, zero out and set needs to zero position (don't put needles on all the way). Plug the cluster (not rebuilt yet) in a couple times to see if needles reset to zero each time. Once your sure they are zero'd out, carefully put everything back together and re-install.

 

[thumper_ehhhhh]

It could be a couple of things. Over sized or undersized tires. gears have been changed. electrical issues. If you have a good tranny shop that you trust get them to look at it. Sometimes they can change the settings in the computer for tire size to gears. Maybe the last person who owned it had monster tires on it and had it set to them so with stocker tires on it it will give a wonky reading.

 

[Popeye]

The needles are at zero when shut off, i.e. when at a stop light the speedo will show zero. I verified the computer when i got my BB tune done. As far as the computer is concerned all reading are accurate.

This is why i am at a dead end as to the issue.

 

[99Yuk]

My gauges are also verified as being off. Especially my speedo.
I pretty much use one of the slots in my scan gauge as my speed indicator.

I figured that it's pretty much a fact of life that mechanical dash indicators are going to be wrong. I just learned to live with it. And bought a scan gauge!



If your dash is indicating 144kph when your only doing 100kph, look at the bright side! If you travel at what your speedo says is 115kph, You'll never get a speeding ticket from our friends the OPP!

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Hmm, just thought of this. And it may suck. If your speedo says 144kph, then won't it affect your kms count? I mean, won't it add an aditional 44kms to a real 100kms trip? Won't that suck for resale value, if it's artificailly inflated by 44%? Now I see why you would want this fixed, pronto! Maybe you can have Justin reflash to accomodate?

 

[Popeye]

LOL i've been looking at the bight side all this time, it's the just the honking of others that i can't get used to. thanks man, you just pushed me over the 'Scan Gauge II" edge.