84 vehicle speed sensor
Thread Starter
Intermediate
Joined: Oct 2008
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84 vehicle speed sensor
I had my dash cluster rebuilt and the speedometer only registered about half the speed I was traveling.
I took the vehicle speed sensor out and I am going to replace it but have no idea what to put back in. I do not know what gear ratio rearend I have is the problem. Plus I don't even know if this is the corrective action for my orginal problem.
Anyone have any wisdom to share?
I took the vehicle speed sensor out and I am going to replace it but have no idea what to put back in. I do not know what gear ratio rearend I have is the problem. Plus I don't even know if this is the corrective action for my orginal problem.
Anyone have any wisdom to share?
Le Mans Master
Joined: Sep 2006
Posts: 6,050
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From: Phoenix AZ
2021 C4 of the Year - Modified Finalist
Well, first, more history is needed.
1. Why did u pull the cluster, and was it accurate prior to exchanging it?
2. Is the trans the one that came with the car?
3. how bout the rear end? original?
4. crawl under the car with a mirror, and a flashlight. move th mirror around under the center section of the rear end. shine flashlight onto mirror, and read the ratio, part number, and some other info.
Remember, it will be backwards.
Note:
the vehicle speed sensor reads out in pulses per mile.
The frequency (I think) is 1000 pulses per mile. If your speedo is half, then you probably have the wrong VSS.
There are two VSS. one has 2 pulses per revolution, and the other one has 4.
You obviously need one that has 4. THe 2 pulser unit may have come out of an impala or camaro.
1. Why did u pull the cluster, and was it accurate prior to exchanging it?
2. Is the trans the one that came with the car?
3. how bout the rear end? original?
4. crawl under the car with a mirror, and a flashlight. move th mirror around under the center section of the rear end. shine flashlight onto mirror, and read the ratio, part number, and some other info.
Remember, it will be backwards.
Note:
the vehicle speed sensor reads out in pulses per mile.
The frequency (I think) is 1000 pulses per mile. If your speedo is half, then you probably have the wrong VSS.
There are two VSS. one has 2 pulses per revolution, and the other one has 4.
You obviously need one that has 4. THe 2 pulser unit may have come out of an impala or camaro.
Last edited by coupeguy2001; Feb 12, 2010 at 11:56 PM.
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Intermediate
Joined: Oct 2008
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I pulled the green driven gear out of the tranny. It has 1/2 of three teeth missing. I know I will replace it as soon as I find one somewhere, Napa and others don't have it. However, what would cause such damage?
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Race Director
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Age.
Or a worn Case bushing that supports the rear planetary ring gear.
Thread Starter
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Joined: Oct 2008
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I have replaced both speed gear and the vehicle speed sensor on the transmission. This did not correct the problem.
Could it be something in the dash cluster?
The speed readout is about half of what it should be and it throws the miles per gallon readout off too.
Could it be something in the dash cluster?
The speed readout is about half of what it should be and it throws the miles per gallon readout off too.
return cluster to your rebuild facility for testing.
