VSS signal from ABS pickup?
12-29-2014, 06:54 AM
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VSS signal from ABS pickup? Since I installed my new transmission, I no longer have a provision for a speedometer cable. I was using that before with the signal generator from autometer for my VSS signal. Has anyone ever used the signal from the reluctor wheel in the spindle to generate the VSS signal? If so, can you share the particulars?
12-29-2014, 08:58 AM
#2
Depends on the sensor type. All the ecu needs is a sine wave signal with adequate voltage. I bought a generic sensor and used it with the reverse gear in a T10 transmission as a reluctor. The voltage will depend on the sensor, distance to reluctor, and reluctor speed, so that takes some adjustment.
Jags that run also sells a reluctor/sensor that mounts to the differential.
Jags that run also sells a reluctor/sensor that mounts to the differential.
12-29-2014, 10:22 AM
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Since I installed my new transmission, I no longer have a provision for a speedometer cable. I was using that before with the signal generator from autometer for my VSS signal. Has anyone ever used the signal from the reluctor wheel in the spindle to generate the VSS signal? If so, can you share the particulars?
Andrew
12-29-2014, 10:45 AM
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That's exactly what I wanted to know!
"Luckily, I have ATS spindles that have a built in ABS sensors in the C5/6 hubs. Dorman sells the ABS jumper harness that fits the C5/6 ABS sensor: PN 970-007."
"One of the leads needs to be grounded, while the other lead is the signal wire. It doesn't matter which is which. Run the signal wire to the Autometer gauge and recalibrate. The ABS sensor will start sending pulses after 2-3 turns of the wheel.
The C5/6 hubs have a 48 tooth reluctor wheel. I am running 255/40-18 tires in the front, which according to TireRack, are 801 turns per mile, so for the two mile calibration period, they will turn 1602 times.
1602 x 48 = 76,896 pulses per 2 miles. Having that information, you don't even need to measure out an accurate 2 mile stretch of road. I started my calibration and when the counter on the speedo got to 76,000 I stopped it. I compared the speedo reading to the GPS reading on my phone and the speedo was slow by about 2 mph. I assumed that the GPS is accurate. So I repeated the calibration and stopped it when the counter got to 74,000 and now the speedo reads exactly the same as the GPS"
Put that here for anyone that wants to know. I assume you can feed the same signal into the VSS input for the computer?
"Luckily, I have ATS spindles that have a built in ABS sensors in the C5/6 hubs. Dorman sells the ABS jumper harness that fits the C5/6 ABS sensor: PN 970-007."
"One of the leads needs to be grounded, while the other lead is the signal wire. It doesn't matter which is which. Run the signal wire to the Autometer gauge and recalibrate. The ABS sensor will start sending pulses after 2-3 turns of the wheel.
The C5/6 hubs have a 48 tooth reluctor wheel. I am running 255/40-18 tires in the front, which according to TireRack, are 801 turns per mile, so for the two mile calibration period, they will turn 1602 times.
1602 x 48 = 76,896 pulses per 2 miles. Having that information, you don't even need to measure out an accurate 2 mile stretch of road. I started my calibration and when the counter on the speedo got to 76,000 I stopped it. I compared the speedo reading to the GPS reading on my phone and the speedo was slow by about 2 mph. I assumed that the GPS is accurate. So I repeated the calibration and stopped it when the counter got to 74,000 and now the speedo reads exactly the same as the GPS"
Put that here for anyone that wants to know. I assume you can feed the same signal into the VSS input for the computer?
12-29-2014, 09:23 PM
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I used the ABS signal from the reluctor in the 8.8 Ford rear end in my Jeep as I did not have a VSS on the transfer case. It worked just fine. I just had to do the math to get the calibration correct as it was 108 teeth on the ring gear versus 40 pulses per revolution of the trans output shaft.
12-30-2014, 09:25 AM
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I had not seen Andrew's post previously but he has done nearly exactly what I planned to do with my Cobra IRS ABS rings.
Only things I would ad to discussion are:
You really don't even need to drive the car to count the pulses if the pulses come from the rear end. Just put the rear up on jack stands and you can do exactly the same process in your driveway. This could give you some really good resolution if you physically turn the wheel by hand towards the end to get the number of pulses closer. If the pulses come from the front tire you can still spin by hand but it will be a whole lot of tire spinning.
You can get an effective rolling diameter by measuring the distance traveled over a given number of tire rotations. IE, if the tire rotates 10 times and the measured distance on the ground is say 67 feet, then 67 feet / 10 = 6.7 feet/rev, which is 80.4 inches/rev, which is 80.4"/3.14 = 25.6" effective diameter.
Measuring effective rolling diameter may help with the calibration if the measurements are good. Sometimes GPS can be off a bit but really worst case inaccuracy for GPS non WAAS is about 45 feet / 5280 feet which is about .9%.
Only things I would ad to discussion are:
You really don't even need to drive the car to count the pulses if the pulses come from the rear end. Just put the rear up on jack stands and you can do exactly the same process in your driveway. This could give you some really good resolution if you physically turn the wheel by hand towards the end to get the number of pulses closer. If the pulses come from the front tire you can still spin by hand but it will be a whole lot of tire spinning.
You can get an effective rolling diameter by measuring the distance traveled over a given number of tire rotations. IE, if the tire rotates 10 times and the measured distance on the ground is say 67 feet, then 67 feet / 10 = 6.7 feet/rev, which is 80.4 inches/rev, which is 80.4"/3.14 = 25.6" effective diameter.
Measuring effective rolling diameter may help with the calibration if the measurements are good. Sometimes GPS can be off a bit but really worst case inaccuracy for GPS non WAAS is about 45 feet / 5280 feet which is about .9%.
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12-30-2014, 09:54 AM
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sounds good, I'm going to try it off of my left rear hub. I have the factory sensor from the C4 IRS in place. And it just so happens that I used a 4th gen bulkhead connector for the fuel pump wiring, but it also has the ABS connections too! makes it real clean looking, I'll put up a pic and share results if it works.
12-30-2014, 05:24 PM
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sounds good, I'm going to try it off of my left rear hub. I have the factory sensor from the C4 IRS in place. And it just so happens that I used a 4th gen bulkhead connector for the fuel pump wiring, but it also has the ABS connections too! makes it real clean looking, I'll put up a pic and share results if it works.
Andrew