Is it? I was just wondering becuase I recently swapped in a T-5 into my 88GTA.. I bought a new VSS and used the gear off of the mechanical sender that was in the tranny. But it reads about 5 MPH slow. So would my odometer be inacurate? I was also wondering how would I go about fixing the reading slow problem?

Thanks in advance.

Jess

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1988 GTA - 5.0 Auto now with 5-speed power!
1989 Firebird - 2.8 5-speed: Sold

My Page - http://transam.freeservers.com
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Maybe. If your speedometer gears in the transmission are off, then both will be incorrect, but if your speedo is out of calibration then your odometer could still be correct.

 

If the speedo is off then the odometer is also of the same %.

 

Yes, if the speedo is off so will the odometer.

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"Rice burners are like tampons...Every pu$$y has to have one"
'86 IROC
T-TOPS, TINTED WINDOWS, BRAKE LIGHT BLACKOUTS
GM GOODWRENCH 350
EDELBROCK TES HEADERS
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KN AIRFILTER
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3:73 Posi
Rebuilt 700R4
B&M Megashifter, 5" Autometer Tach w/shift lite

 

No, it's what the first guy said.

If the gears in the tranny are CORRECT and it's simply the speedometer out of calibration or the head is messed up, the odometer will still be correct because it is GEAR DRIVEN.

If the transmission gears are incorrect, then both will be off.

 

If speedometer is off then the odometer is off. If the speedo is electric then the odometer is also electric. There is no cable on elec. speedo equipped cars.

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1992 Z/28 305 Purple Haze

[This message has been edited by mr2fast4u (edited October 23, 2001).]

 

The odometer's not electric, I took one apart a day or two ago and had the little gears just like the non-electric?

 

then the gears would be driven by the speedo and therefore be off the same percent as the speedo

 

Hawk and Apeiron are correct. I see what you other guys are saying, but if the speedo itself is messed up AFTER the little gear in the speedo itself, then you would still be registering the correct miles on the odometer and tripometer, while showing the incorrect MPH.

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1989 IROC-Z 5.7L
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ProBuilt 700R4, PI Vigilante 2800 stall lockup
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I concur with Hawk, Aperion and Omar: the speedo CAN be off while the odometer is reading correctly.

I recently was running my scan tool (Diacom) on a buddy's 89 GMC Van and I noticed a large difference between what his speedo said and what Diacom displayed. To verify the error, I followed him in my car (which has a very accurate speedo reading) and confirmed that his speedo was off by 20%. He then when through a "mile marker" and his odometer was almost bang on.

So yes, your odometer may be reading correctly, but the speedo can still be off. If you hook your car to a scan tool, the MPH can be compared between the two as the scan tool will use the VSS.

 

A good example would be to take the needle off the speedometer and put it in the wrong spot. Now your speedometer will be off but the odometer will still be correct.

That's the procedure I'm going to use to calibrate my new speedometer, since I had the needle off:

1) Calibrate the VSS to the tachometer (which seems to be pretty close)--this is a necessary step because of the T56.
2) Then calibrate the needle to the VSS.

 

Thanks for the info guys, I guess I'll keep an eye on the odometer on the way home from school see if I can varify it being accurate or not. I'm also not sure if the gear on the VSS is the correct one as it came off of the mechanical sender of the T5 out of an 87 Iroc. Unfortuneatly I don't have access to a san tool at this time to check it all.

Thanks again,

Jess

 

got a weird one here. My speedo is correct (reasonably close), verified with my scanner (DataMaster) and traffic flow on the freeway, and my girlfriends factory new Nissan, but my odometer is 65% off, confirmed on multiple occasions looking at the mile-markers alongside the highway. my odo reads 16.5 miles when I've gone 10 miles. the odo rolls over smoothly, no jerky digit action, looks perfectly normal until you notice the mile-markers. My computer seems to be happy. My trip odo is useless since it kicked the bucket long time ago. I've given up on solving this one, but I scan the VSS posts every now and then. I'm baffled, but it's liveable.