Speedometer calibration can be a bit tricky, so pay attention! First of all, read everything here, you may not need to adjust anything, you may have other, larger issues. Start with the following:
- Check your tire size and make sure it is the correct diameter to read correctly. (Stock is 225/50R16, which is 24.9 inches)
- Check your odometer, make sure it is accurate before anything else.
If your odometer IS NOT correct
- You've got gearing issues, are your tires incorrectly sized? If not, you've got a problem related to the speedometer gearing in the transmission, usually due to one of 2 things: either the transmission or differential was changed out at some point.
- You're going to need to figure out what was changed, if you have the correct differential, you'll need to change the speedometer gears in the transmission. If you have the incorrect differential, you can either change the differential gears or the speedometer gears in the transmission to match your new differential.
- After you have your gearing corrected, and you've now confirmed that your odometer is reading correctly, check your speedometer for accuracy. If it is not correct, continue with the following instructions.
If your odometer IS correct
- Your speedometer cable is spinning at the correct speed, which is a good start. Typically speaking all Toyota speedometer/odometers are calibrated to the same specification, which is 637 revs = 1 km, or 1026 revs = 1 mile. What that means is, all A70 speedometers are interchangeable, so don't worry that you've got the wrong speedometer in there and that is what's causing the problem, it's not.
- Check how much out your speedometer is, if it is a consistent speed out all the time (it reads 25mph when you're actually going 15mph and it reads 85mph when you're actually going 75mph), chances are the needle is in the wrong spot and just needs to be moved. Carefully remove the gauge cluster and pop off the speedometer needle. Reinstall it to offset the amount you are reading incorrectly. When it is at rest it really should sit perfectly at or just below 0 on the gauge.
- If your speedometer is out by a percentage (it reads 25mph when you are actually doing 22mph and it reads 85mph when you're actually going 76mph), chances are it needs to be adjusted, if it is reading too high, you'll need to tighten the tension spring on the back of the speedometer. If it is reading too low, you'll need to reduce the tension on the spring. If you need to adjust the speedometer tension spring, continue to the following instructions.
Adjusting the speedometer tension spring:
- You need to get the speedometer right out of the gauge cluster, I'm not going to get into that here, but you need access to the back side of the speedometer. Get cracking.
- Once you have it out, you'll need to adjust the tension, now I've found that you have approximately +/- 15% adjustment on the speedometer, so if it's beyond that, I'd suggest replacing the speedometer.
This is what the speedometer looks like once the gauge face and needle are removed. You can go to this level, but it is not required. You can to the adjustment from the back side through the adjuster hole.
To tighten the spring, move the adjuster downward (this will decrease the speed shown on the speedometer). To loosen the spring, move the adjuster upward (this will increase the speed shown on the speedometer). This image illustrates how moving the lever will change the speed shown on your speedometer:
- You're going to have to do some trial and error with this before you get it just right. I hope you have some time on your hands, this can take quite a while.
Jeff
- Check your tire size and make sure it is the correct diameter to read correctly. (Stock is 225/50R16, which is 24.9 inches)
- Check your odometer, make sure it is accurate before anything else.
If your odometer IS NOT correct
- You've got gearing issues, are your tires incorrectly sized? If not, you've got a problem related to the speedometer gearing in the transmission, usually due to one of 2 things: either the transmission or differential was changed out at some point.
- You're going to need to figure out what was changed, if you have the correct differential, you'll need to change the speedometer gears in the transmission. If you have the incorrect differential, you can either change the differential gears or the speedometer gears in the transmission to match your new differential.
- After you have your gearing corrected, and you've now confirmed that your odometer is reading correctly, check your speedometer for accuracy. If it is not correct, continue with the following instructions.
If your odometer IS correct
- Your speedometer cable is spinning at the correct speed, which is a good start. Typically speaking all Toyota speedometer/odometers are calibrated to the same specification, which is 637 revs = 1 km, or 1026 revs = 1 mile. What that means is, all A70 speedometers are interchangeable, so don't worry that you've got the wrong speedometer in there and that is what's causing the problem, it's not.
- Check how much out your speedometer is, if it is a consistent speed out all the time (it reads 25mph when you're actually going 15mph and it reads 85mph when you're actually going 75mph), chances are the needle is in the wrong spot and just needs to be moved. Carefully remove the gauge cluster and pop off the speedometer needle. Reinstall it to offset the amount you are reading incorrectly. When it is at rest it really should sit perfectly at or just below 0 on the gauge.
- If your speedometer is out by a percentage (it reads 25mph when you are actually doing 22mph and it reads 85mph when you're actually going 76mph), chances are it needs to be adjusted, if it is reading too high, you'll need to tighten the tension spring on the back of the speedometer. If it is reading too low, you'll need to reduce the tension on the spring. If you need to adjust the speedometer tension spring, continue to the following instructions.
Adjusting the speedometer tension spring:
- You need to get the speedometer right out of the gauge cluster, I'm not going to get into that here, but you need access to the back side of the speedometer. Get cracking.
- Once you have it out, you'll need to adjust the tension, now I've found that you have approximately +/- 15% adjustment on the speedometer, so if it's beyond that, I'd suggest replacing the speedometer.
This is what the speedometer looks like once the gauge face and needle are removed. You can go to this level, but it is not required. You can to the adjustment from the back side through the adjuster hole.
To tighten the spring, move the adjuster downward (this will decrease the speed shown on the speedometer). To loosen the spring, move the adjuster upward (this will increase the speed shown on the speedometer). This image illustrates how moving the lever will change the speed shown on your speedometer:
- You're going to have to do some trial and error with this before you get it just right. I hope you have some time on your hands, this can take quite a while.
Jeff
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. Is there any hope of fixing that? I remember back when I had my old E30 Bimmer that you could buy an actual replacement gear because people would always go to reset the trip while moving, which was a big no no and stripped the teeth off the thing.
