will the speedo work off a wheel speed sensor?

[Tunerbuilder]

So I just acquired my first Eclipse and what I thought to be a minor issue, has become quite the ordeal . I was looking into the inop speedo issue; and after 15 minutes of diag I realized that my vss is not just inoperable, its missing all together. the vss hole in the tranny had been filled with silicone and the 10 mm bolt was loose . Before I remove the silicone and stick my finger in the vss hole to find out if the plastic ring is still in place/install a new vss; I need to know if its possible to get the signal from a wheel speed sensor to achieve factory speedo operation. I believe the wss and the vss use the same signal type and voltage level; so correct me if I'm wrong, but this "in theory" could work . I need to know if this has a good chance of either working or killing the speedometer itself. My dsm will be my daily when I leave for school in march, so any help is appreciated.

 

[Insane20]

It could but I seriously doubt it, seeing as the wheel speed sensor is for the abs. I would just look into getting a replacement.

 

[Tunerbuilder]

A replacement vss is 4 days away, and I'm not messing with the silicone plug unless I have to.

 

[Phantom DSM]

So I just acquired my first Eclipse and what I thought to be a minor issue, has become quite the ordeal . I was looking into the inop speedo issue; and after 15 minutes of diag I realized that my vss is not just inoperable, its missing all together. the vss hole in the tranny had been filled with silicone and the 10 mm bolt was loose . Before I remove the silicone and stick my finger in the vss hole to find out if the plastic ring is still in place/install a new vss; I need to know if its possible to get the signal from a wheel speed sensor to achieve factory speedo operation. I believe the wss and the vss use the same signal type and voltage level; so correct me if I'm wrong, but this "in theory" could work . I need to know if this has a good chance of either working or killing the speedometer itself. My dsm will be my daily when I leave for school in march, so any help is appreciated.

The wheel speed sensor is for abs. unfortunately you will have to relpace the Vss. i cant believe someone plugged it with silicone WTF
Sorry to hear man, but be careful none of that silicone drops into the tranny. if the bottom half with the gear is in the tranny and covered with silicone, then im sure you can loosen th 10mm and remove the bottom portion. For a Fwd manual trans the part number is : FWD M/T 95-99: MD746492
Hopefully you still have this harness connector as well.

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[Tunerbuilder]

Well, it was worth a shot. thanks for the info. But just to clarify, I would be splicing the signal wire and ground of the vss into the wss signal and ground. Not literally inserting a wss into the vss hole in the tranny. I'm aware the wss is operated by the passing of teeth in front of a magnet changing polarity, is the vss signal altered by a change in polarity as well? If they are both polarity based signals, would the wss signal itself be a suitable substitute for the vss signal to the ecu?

I'm just worried about the state of the gear in the tranny that meshes with the vss. It may have fallen into the tranny, which could be why the vss was removed and filled with silicone in the first place.

 

[Phantom DSM]

Well, it was worth a shot. thanks for the info. But just to clarify, I would be splicing the signal wire and ground of the vss into the wss signal and ground. Not literally inserting a wss into the vss hole in the tranny. I'm aware the wss is operated by the passing of teeth in front of a magnet changing polarity, is the vss signal altered by a change in polarity as well? If they are both polarity based signals, would the wss signal itself be a suitable substitute for the vss signal to the ecu?

I'm just worried about the state of the gear in the tranny that meshes with the vss. It may have fallen into the tranny, which could be why the vss was removed and filled with silicone in the first place.

Idk if an wss will give correct signal for speedo to read. Heres an in depth discussion with data. Post #16 by Gofer discussed circuit and signal. A vss would be the only viable option i believe, but maybe this link can help you for now.
http://www.dsmtuners.com/forums/newbie-forum/422570-vss-circuit-repair.html

 

[Tunerbuilder]

Thanks for the link, good read! From what I understand after reading that, they both operate under the same basic parameters. In the wss, the toothed ring is the magneto resistive element (mre) and passes by a stationary magnet. In the vss, the sensor itself is a circular stationary magnet and the mre centered inside said magnet is spun by the gear in the transmission. So in theory they both produce the same type of signal via polarity changes. I just need to know if the wave form is the same for both sensors, I guess I'll try it tomorrow and see if it works.

 

[steve]

I can't comment on the signal levels but I can comment that the number of pulses are not compatible. The wheel sensor generates far more pulses than the VSS per rotation of the wheels.

 

[bryanwheat]

Thanks for the link, good read! From what I understand after reading that, they both operate under the same basic parameters. In the wss, the toothed ring is the magneto resistive element (mre) and passes by a stationary magnet. In the vss, the sensor itself is a circular stationary magnet and the mre centered inside said magnet is spun by the gear in the transmission. So in theory they both produce the same type of signal via polarity changes. I just need to know if the wave form is the same for both sensors, I guess I'll try it tomorrow and see if it works.

Why did you even ask if you were just going to do it anyway. Adding another circuit into the abs system is a bad idea. What's to say that the added voltage from the extra circuit won't tell the abs module to do something that makes the car lose control. By the the gear on the diff is metal, not plastic. The plastic gears are in the 420a transmissions.

 

[wrencher]

The signals are not the same in amplitude or voltage.

The wheel speed sensor is a permanent magnet generator style sensor.
It is a 2 wire sensor that produces voltage & a frequency proportional to rpm.
(very low voltage @ low speed)

The VSS is roughly a hall effect sensor.
A 3 wire sensor with a 5 volt reference & a transistor for a stronger voltage with a variable frequency dependent upon rpm.

Not compatible signals what so ever. It takes both wires to read the wss signal since it is an A/C signal as well.

The speedo head has to have the correct sensor feeding it the proper voltage & amperage to operate.
I have been working on cars for 20+ years & have tested many signals with a digital oscilloscope.
I know what signals they make & their individual attributes , these 2 are not even close.

You have to fix the vehicle speed sensor, don't waste your time with anything else.

 

[Tunerbuilder]

The signals are not the same in amplitude or voltage.

The wheel speed sensor is a permanent magnet generator style sensor.
It is a 2 wire sensor that produces voltage & a frequency proportional to rpm.
(very low voltage @ low speed)

The VSS is roughly a hall effect sensor.
A 3 wire sensor with a 5 volt reference & a transistor for a stronger voltage with a variable frequency dependent upon rpm.

Not compatible signals what so ever. It takes both wires to read the wss signal since it is an A/C signal as well.

The speedo head has to have the correct sensor feeding it the proper voltage & amperage to operate.
I have been working on cars for 20+ years & have tested many signals with a digital oscilloscope.
I know what signals they make & their individual attributes , these 2 are not even close.

You have to fix the vehicle speed sensor, don't waste your time with anything else.

That's exactly what I needed to know! Thankyou!

By the the gear on the diff is metal, not plastic. The plastic gears are in the 420a transmissions.

So im guessing that means I won't have issues with it separating from the diff like the plastic one?