LS engine swap info - The 1947 - Present Chevrolet & GMC Truck Message Board Network

Wildkarde · 04-26-2018, 12:43 AM

The ECM is looking for 40 pulses per driveshaft revolution(this is tens of thousands of pulses per mile), but it uses some math to determine how many pulses per mile that is since it changes with gear ratio/tire size. This is adjustable in tuning software.

The ECM can output a vehicle speed signal on one of two wires, one sends 4000 pulses per mile, usually used for speedometers/cruise, the otther 128k pulses per mile, used for ABS and traction control.

You need to know your rear end gearing and tire size to make the calculations you need. Is your current speedo gear in the trans giving you a correct speed reading on the speedo?

04-26-2018, 12:43 AM	#34
Wildkarde Registered User Join Date: Mar 2018 Location: Ardmore Posts: 100	Re: LS engine swap info The ECM is looking for 40 pulses per driveshaft revolution(this is tens of thousands of pulses per mile), but it uses some math to determine how many pulses per mile that is since it changes with gear ratio/tire size. This is adjustable in tuning software. The ECM can output a vehicle speed signal on one of two wires, one sends 4000 pulses per mile, usually used for speedometers/cruise, the otther 128k pulses per mile, used for ABS and traction control. You need to know your rear end gearing and tire size to make the calculations you need. Is your current speedo gear in the trans giving you a correct speed reading on the speedo?



Register or Log In To remove these advertisements.

Register or Log In To remove these advertisements.