Odometer reading ok. Speedometer is not.
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Junior Member
Joined: Jun 2012
Posts: 42
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Car: Trans Am
Engine: 305
Transmission: TH350
Odometer reading ok. Speedometer is not.
Hi.
I Have a 82' firebird trans am with 305 engine (carbs) and TH350 transmission.
My speedometer is giving me a reading that is around 27 - 30 % too fast.
I've looked in to changing gears but then I discovered that my odometer is correct.
1. Can i fix this issue with changing speedometer gears?
2. If my speedometer is broken, is there a way to repair/recalibrate it?
Any help greatly appreciated / Björn
I Have a 82' firebird trans am with 305 engine (carbs) and TH350 transmission.
My speedometer is giving me a reading that is around 27 - 30 % too fast.
I've looked in to changing gears but then I discovered that my odometer is correct.
1. Can i fix this issue with changing speedometer gears?
2. If my speedometer is broken, is there a way to repair/recalibrate it?
Any help greatly appreciated / Björn
Member

Joined: May 2012
Posts: 167
Likes: 1
From: Santa Clara, CA
Car: Black 1991 Z28
Engine: 5.7 TPI
Transmission: Automatic
Axle/Gears: I have no Idea
Re: Odometer reading ok. Speedometer is not.
Hi.
I Have a 82' firebird trans am with 305 engine (carbs) and TH350 transmission.
My speedometer is giving me a reading that is around 27 - 30 % too fast.
I've looked in to changing gears but then I discovered that my odometer is correct.
1. Can i fix this issue with changing speedometer gears?
2. If my speedometer is broken, is there a way to repair/recalibrate it?
Any help greatly appreciated / Björn
I Have a 82' firebird trans am with 305 engine (carbs) and TH350 transmission.
My speedometer is giving me a reading that is around 27 - 30 % too fast.
I've looked in to changing gears but then I discovered that my odometer is correct.
1. Can i fix this issue with changing speedometer gears?
2. If my speedometer is broken, is there a way to repair/recalibrate it?
Any help greatly appreciated / Björn
Are you reading the MPH or the KM?
J/K
Thread Starter
Junior Member
Joined: Jun 2012
Posts: 42
Likes: 0
Car: Trans Am
Engine: 305
Transmission: TH350
Re: Odometer reading ok. Speedometer is not.
I'm reading the KM/h. When i'm traveling in 50 km/h the meter shows 65. When i go in 80 the meter shows around 110.
My odometer is calibrated for km/h and seems to be accurate.
My odometer is calibrated for km/h and seems to be accurate.
Thread Starter
Junior Member
Joined: Jun 2012
Posts: 42
Likes: 0
Car: Trans Am
Engine: 305
Transmission: TH350
Re: Odometer reading ok. Speedometer is not.
Trying to bump this thread. Since I have a carburated engine (LG4) there is no VSS to take into consideration. It seems my only option is to replace the speedometer.
Or does anyone know a way to repair it? (I've checked my shopmanual but all it's saying about my problem is that the speedometer needs to be reparied. duh)
Any help greatly appreciated / Björn
Or does anyone know a way to repair it? (I've checked my shopmanual but all it's saying about my problem is that the speedometer needs to be reparied. duh)
Any help greatly appreciated / Björn
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Joined: Jan 2000
Posts: 20,981
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From: Mercedes Norte, Heredia, Costa Rica
Car: 1984 Z28 Hardtop
Engine: 383 Carb
Transmission: 4L60
Axle/Gears: 3.54 Dana 44
Re: Odometer reading ok. Speedometer is not.
Wouldn't matter if there was a VSS, if the odometer right then the problem is still in the speedo head mechanism.
No user-serviceable parts inside a speedometer. Pretty much has to go to a shop for remagnetization and recalibation.
No user-serviceable parts inside a speedometer. Pretty much has to go to a shop for remagnetization and recalibation.
Thread Starter
Junior Member
Joined: Jun 2012
Posts: 42
Likes: 0
Car: Trans Am
Engine: 305
Transmission: TH350
Re: Odometer reading ok. Speedometer is not.
For the record: According to the papers from "transportstyrelsen" a govt. authority in sweden my odometer should read kmh. But it does not. Before ordering a new speedo a checked with a GPS more thoroughly than I did before. My odo reads miles. And it reads around 23% too much. Next step is to find the right gears or simpy order an ratio adapter. Have posted this in the trans. part of this wonderful forum.
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Member

Joined: May 2012
Posts: 167
Likes: 1
From: Santa Clara, CA
Car: Black 1991 Z28
Engine: 5.7 TPI
Transmission: Automatic
Axle/Gears: I have no Idea
Re: Odometer reading ok. Speedometer is not.
I would try swapping out the instrument cluster. They're on Ebay all the time.
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