Topic: Incorrect reading on the Speedometer

[Reblacklaf]

Yes, I have an issue with my 2008 Solstice GXP. We have done several upgrades and last month notice that the speedo was off by about 5-7%. It was reading higher than the actual speed . Using the HP tuner we tried all the normal corrections used for the manual transmissions but are unable to correct this. None of them seem to work with my automatic setup. Does anyone have any experience with recalibrating the speedo on an automatic equipped car?

Thank you in advance.

Randy

[Critterman]

All speedo's are off by that amount.

[Steelmesh]

Yes, I have an issue with my 2008 Solstice GXP. We have done several upgrades and last month notice that the speedo was off by about 5-7%. It was reading higher than the actual speed . Using the HP tuner we tried all the normal corrections used for the manual transmissions but are unable to correct this. None of them seem to work with my automatic setup. Does anyone have any experience with recalibrating the speedo on an automatic equipped car?

Thank you in advance.

Randy

You will need to change the Final Drive Ratio in HPTuners, this works for sure.

[Steelmesh]

Higher numerical gear ratio should drop your speedo, so do 3.73 * 1.06 = 3.95, which is +6% added to 3.73 ratio.

Also just noticed a comment about someone physically altering the speedometer needle in the gauge.  With that, I suggested checking the speedo error at two points, say 30 mph and 60 mph.  If both error amounts are the exact same, that means there is a physical problem with the needle; HOWEVER, if the error scales with speed than it is a calculation error that you would use HPT to recalibrate in the computer.  Error scaling, I mean for example at 30 mph GPS says 27 or -3 mph, at 60 mph GPS says 54 or -6 mph...that would mean the calculation is off and nothing to do with the physical needle on the gauge.

[DeepBlueGXP]

Do you have stock tires?  Changing tire size will affect the speedometer

[RedOne07]

Please delete

[DaveOC]

My Solstice is right on the ball at any speed.

Mine reads 3 - 5 mph slower than you are actually going, per my GPS devices.

 

.

[TomatoSoup]

Mine is accurate too.  However, my wife's Mazda (CX-5) runs about 2-3 mph slower on the speedo that the GPS says.

[Reblacklaf]

We have tried changing the rear axle ratio and even moving the pointer. No matter which we do it constantly reads off by 5%.

Randy

[Steelmesh]

We have tried changing the rear axle ratio and even moving the pointer. No matter which we do it constantly reads off by 5%.

Randy

Sorry to mislead you, I am running the E67 ECU, you have a totally different one with the direct injected LNF, E69. 

I did a little research and it got weird, something about setting the FDR to 1:1 and changing the VSS pulses...  You may need to create a post in that forum to get the process to correct your speedo, looks like it isn't as easy as changing the FDR.

https://forum.hptuners.com/showthread.php?47750-Can-you-guys-do-me-a-little-favor