ECM Ground?
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Joined: Feb 2004
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From: Blue Springs MO
ECM Ground?
Installing an LC-1 tommorrow and the instructions say to ground the analog 1 output ground to the ECM ground in order to satisfy the computers narrow band sensor requirement. Can anyone tell me how to locate the main ground for the ECM?
Melting Slicks
Joined: Oct 2002
Posts: 3,193
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From: Cincinnati Oh
no. the braided line is the engine-chassis ground backup cable (in tandem with the battery cable).
Just ground it to the engine block or the intake manifold - it's essentially the same ground. You'll want to stay away from the alternator and injectors, so maybe in the rear passenger side on the intake manifold is a good spot. You ideally want to the LC-1 to have it's own ground (NOT sharing a bolt with the battery cables, other grounds, etc) and make sure both the connector and the ground surface are flat and clean.
When you ground it - then program the analog output to put out a constant 5 volts, plug it in and measure what you actually read through your datalogger. This is the voltage offset and should be pretty small - you can then "adjust" your narrowband emulation by adding this amout to both the low and high ranges to get an accurate reading out of the O2, no matter where you ground it to.
IE if the narrowband default is 0.100 volts to 1.00 volts (~14.0 to 15.0 AFR), and you have 4.92 volts readout when doing the "calibration," then your voltage offset is -0.08 volts. You'd modify the narrowband emulation to 0.02 - 0.92 volts (the original values - 0.08volts due to sensor voltage offset).
Hope this helps?
Just ground it to the engine block or the intake manifold - it's essentially the same ground. You'll want to stay away from the alternator and injectors, so maybe in the rear passenger side on the intake manifold is a good spot. You ideally want to the LC-1 to have it's own ground (NOT sharing a bolt with the battery cables, other grounds, etc) and make sure both the connector and the ground surface are flat and clean.
When you ground it - then program the analog output to put out a constant 5 volts, plug it in and measure what you actually read through your datalogger. This is the voltage offset and should be pretty small - you can then "adjust" your narrowband emulation by adding this amout to both the low and high ranges to get an accurate reading out of the O2, no matter where you ground it to.
IE if the narrowband default is 0.100 volts to 1.00 volts (~14.0 to 15.0 AFR), and you have 4.92 volts readout when doing the "calibration," then your voltage offset is -0.08 volts. You'd modify the narrowband emulation to 0.02 - 0.92 volts (the original values - 0.08volts due to sensor voltage offset).
Hope this helps?
Last edited by Ramanstud; Mar 16, 2006 at 11:33 AM.
