Conversions & Swaps LSX Engines in Non-LSX Vehicles
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Yet another Gotcha to Look Out For

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Old Jul 21, 2010 | 05:27 PM
  #1  
markeheiden's Avatar
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Default Yet another Gotcha to Look Out For

So during my conversion I needed a VSS to talk to my 2007 ECU. I selected a unit that is compatible (2-wire) with my E-38 that is driven off of the transfer case speedo output. The manufacturer specified that the VSS produced 8-pulses per revolution of drive shaft.

I had the programmer input this number during re-flash and the car ran great but the shift points were extremely high. I could barely get it into 3rd and was going pretty fast (for the dirt) before it did and once in 3rd it jumped back to 2nd with any throttle at all.

So I discoverd last night that there is about a 3-1 reduction gear in the speedo output that slows that VSS pulse generator down to about 3 per revolution instead of 8. I'm having it re-flashed with the actual pulses now and will soon be shifting normally I'm sure!

Keep watchin' out for the gotchas!
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Old Jul 21, 2010 | 09:11 PM
  #2  
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Originally Posted by markeheiden
So during my conversion I needed a VSS to talk to my 2007 ECU. I selected a unit that is compatible (2-wire) with my E-38 that is driven off of the transfer case speedo output. The manufacturer specified that the VSS produced 8-pulses per revolution of drive shaft.

I had the programmer input this number during re-flash and the car ran great but the shift points were extremely high. I could barely get it into 3rd and was going pretty fast (for the dirt) before it did and once in 3rd it jumped back to 2nd with any throttle at all.

So I discoverd last night that there is about a 3-1 reduction gear in the speedo output that slows that VSS pulse generator down to about 3 per revolution instead of 8. I'm having it re-flashed with the actual pulses now and will soon be shifting normally I'm sure!

Keep watchin' out for the gotchas!
Those sensors are rated based on cable speedo revolutions. Most US built vehicles with cable driven speedo's is 1000 revolutions per mile. A 8 pulse sensor outputs 8 pulse per revolution of the cable speedo.

When i reprogram one for the Dakota Digital sensor, usually a value of 3 to 3.5 pulse/drive shaft revolution work out. You can make an excel sheet to get it exact if you know the tooth count in your extension housing drive/driven gears.
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Old Jul 22, 2010 | 01:13 AM
  #3  
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I'm sure 3 will be fine. I'm always in the dirt or sand and with the never ending tire spinning it will be close enough. Now I'm getiin excited about going out and playing again!
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