Speedometer problem
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Joined: Jun 2007
Posts: 52
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From: Germantown WI
Speedometer problem
About a year ago, I had 4.11 gears installed in my 95 M6, and I got a new mail order tune for the car.
Since then, the speedometer display shows 0, 1, 2 or 3, depending on my actual speed (3=approx. 60 mph).
When I log via TTS Datamaster, the log shows the same values (0,1,2,3) in the Mph value.
Using TunerPro RT, I see the "Speedometer Scalar" parameter = 2.00 and the "Speedometer Scalar, Fractional" is set at .59.
Does this mean my PCM thinks I have 2.59 gears and thus the problem with my speedometer values?
Also, the odometer also reads very low. It recorded approx. 0.6 miles on a 10 mile drive.
By the way, I have already replaced the VSS.
Any ideas?
Ron
Since then, the speedometer display shows 0, 1, 2 or 3, depending on my actual speed (3=approx. 60 mph).
When I log via TTS Datamaster, the log shows the same values (0,1,2,3) in the Mph value.
Using TunerPro RT, I see the "Speedometer Scalar" parameter = 2.00 and the "Speedometer Scalar, Fractional" is set at .59.
Does this mean my PCM thinks I have 2.59 gears and thus the problem with my speedometer values?
Also, the odometer also reads very low. It recorded approx. 0.6 miles on a 10 mile drive.
By the way, I have already replaced the VSS.
Any ideas?
Ron
Last edited by Rbuet; May 3, 2011 at 05:02 PM.
Le Mans Master
Joined: Jul 2007
Posts: 5,043
Likes: 7
From: Tampa Florida
Usually - if the VSS has any output voltage what-so-ever the VSS isn't the issue. Your old/used VSS is more than likely in working order. Question: with the the old/used VSS installed did the speedo read 1,2,3 or was it reading "higher" before the "swap".....if so it may be your have a partial problem with the new VSS sensor or the installation.
Quite a few 90-96 clusters can have problems over time...failing speedo/tach is pretty common issue. So the cluster could be part of the problem.
I'm pretty sure you can't "tune"/calibrate speedo values for your year 'vette I believe you have to change the speedo gears on the transmissions output shaft to get the correct value at the ECM - you may want to ask about this in the scan & tune section though.
If your VSS at the ecm/pcm is in fact way off or non existant your car may "run" like crap.
Quite a few 90-96 clusters can have problems over time...failing speedo/tach is pretty common issue. So the cluster could be part of the problem.
I'm pretty sure you can't "tune"/calibrate speedo values for your year 'vette I believe you have to change the speedo gears on the transmissions output shaft to get the correct value at the ECM - you may want to ask about this in the scan & tune section though.
If your VSS at the ecm/pcm is in fact way off or non existant your car may "run" like crap.
Thread Starter
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Joined: Jun 2007
Posts: 52
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From: Germantown WI
From the OP:
I datalog and email the log files to PCMFORLESS. They email revised parameters back. I load into car via their upload program, my laptop and cable.
I use TTS Datamaster for logging.
I also have TunerPro RT, but have not used it yet to change parameters. I'm a novice at this and still learning. Soon, I will make small modifications and upload changes to the car via my laptop and TunerPro RT.
In the case of the speedometer, I can't figure out if I have a mechnical problem or a software issue.
Ron
Ron
I use TTS Datamaster for logging.
I also have TunerPro RT, but have not used it yet to change parameters. I'm a novice at this and still learning. Soon, I will make small modifications and upload changes to the car via my laptop and TunerPro RT.
In the case of the speedometer, I can't figure out if I have a mechnical problem or a software issue.
Ron
Ron
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Thread Starter
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Joined: Jun 2007
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From: Germantown WI
Resolution: STL94LT1 went above and beyond to identify and fix the problem. The problem was that my mail-order tune was setup for a camaro, not a corvette. As a result, the parameters for the speedometer were incorrect.
STL94LT1 not only identified the problem, but modified my existing .bin file to correct it and emailed it back to me!
And a side note . . . overall drivability has improved with the correction because the PCM always thought the car was going 1,2, or 3 mph. My low speed stall problem is also fixed.
What a great guy! Thanks STL94LT1!
STL94LT1 not only identified the problem, but modified my existing .bin file to correct it and emailed it back to me!
And a side note . . . overall drivability has improved with the correction because the PCM always thought the car was going 1,2, or 3 mph. My low speed stall problem is also fixed.
What a great guy! Thanks STL94LT1!
Race Director
Joined: Jan 2005
Posts: 10,641
Likes: 13
From: Slidell Louisiana
Resolution: STL94LT1 went above and beyond to identify and fix the problem. The problem was that my mail-order tune was setup for a camaro, not a corvette. As a result, the parameters for the speedometer were incorrect.
STL94LT1 not only identified the problem, but modified my existing .bin file to correct it and emailed it back to me!
And a side note . . . overall drivability has improved with the correction because the PCM always thought the car was going 1,2, or 3 mph. My low speed stall problem is also fixed.
What a great guy! Thanks STL94LT1!
STL94LT1 not only identified the problem, but modified my existing .bin file to correct it and emailed it back to me!
And a side note . . . overall drivability has improved with the correction because the PCM always thought the car was going 1,2, or 3 mph. My low speed stall problem is also fixed.
What a great guy! Thanks STL94LT1!
then I followed Ron's (from AI) advice and gave Ed Wright a call.
I'm sorry to see that folks still send F-body tunes to Y-body owners.
Congrats on getting the performance you paid for.
Mike
Instructor
Joined: Dec 2009
Posts: 189
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From: New Jersey
I think pcmforless may have done the same thing to me, I have stock gears and my speedo reads correct but on TTS datamaster the values are always 0-7, it seems to only display the 1st digit of my speed though, if im going 10-19 it will say 1, 20-29 will say 2, 30-39 will say 3, etc. Right after getting the tune from them my VATS magically decided to not let the car run for more than 3 sec also and I had to have it disabled, I assume this may have been caused by the f body VATS that is different from the Y body VATS I read about, making its way onto my pcm
Last edited by RustInPeace; May 18, 2011 at 10:05 PM.
