The factory harness NBO2 connector needs these two wires to allow the PCM to properly see a NBO2 signal:
Pin B <- LC-1 yellow (analog 1 output)
Pin A <- LC-1 green or white
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The factory harness NBO2 connector needs these two wires to allow the PCM to properly see a NBO2 signal:
Pin B <- LC-1 yellow (analog 1 output)
Pin A <- LC-1 green or white
I guess there are significant differences between the LC-1 and LM-1 manuals regarding the sensor wires and I don't want to add more here that creates confusion. I'm tempted to post part of a paragraph from the LM-1 manual regarding the analog connection in place of the OEM O² sensor but I think it would be right to do it in a separate thread.
Well I looked at the LC-1 manual and the hints and tricks section for the analog output is the same as what i have in the LM-1 manual. I guess I'm doing what you already attempted by connecting the TAN lead to the RED analog #1 wire and the PURPLE lead to the analog #1 white wire. I'll measure some things before actually connecting to the LM-1 controller to make certain I'm not pushing 12 volts into a 1 volt output circuit. I'll let you know my results and please keep us posted here.
I believe I've got it now. My scanner shows a full range of millivolts right up to 999. There's a few quirks but if it doesn't throw a code I'm happy. :fluffy:
Looky here: http://www.ls1tech.com/forums/pcm-di...-1-lc-1-a.html
Good job...:cheers:
What did you do to achieve this...?
(Yes, why did Innovate change the wire colors between LC-1 and LM-1...?)
Welcome to Differential Inputs:
The PCM's NBO2 input pair (signal_high, signal_low) are known as a "differential input pair"... the PCM sees the NBO2 voltage as the voltage on signal_high wrt signal_low regardless/irrespective of PCM ground...
each of signal_high and signal_low are themselves wrt to PCM ground... in effect the PCM electronically subtracts signal_high_wrt_PCM_ground from signal_low_wrt_PCM_ground to obtain the NBO2 voltage...
the purpose of differential inputs is to subtract out noise... e.g. if ignition secondary induces spikes, the spikes will have the same amplitude on each of signal_high and signal_low, so the spikes become subtracted out, leaving the actual NBO2 voltage intact.
:)
For my LS1/6 with the LM-1 WB controller:
The Analog #1 wire (red) gets connected to the #2 purple wire from the efi loom to the PCM. I made the change when SSpdDmn produced an O2 sensor wiring schematic for a 99 Corvette.
The Analog copper ground wire gets connected to the #2 TAN wire from the efi loom to the PCM.
I previous had the TAN wire connected as I thought it was the high signal. The reason for that was I had checked voltage from the loom and thought it corresponded to the instructions in the LM-1 manual. I had previously thought the purple wire was a heater voltage because it showed more than 12 volts with the key on - engine off. It turns out that the purple wire goes to 1.2 volts on engine start up and the TAN wire goes to .45 volts. It was 4.5 volts before the engine starts. Basically those voltages are reduced by the power of 10 once the engine has started.
The formula you show works. The 1.2 volts minus the .45 volts equals 7.5 volts or more. Not seeing the sine of the signal gives the steady state I suppose. However, there are some quirks which may end up creating a DTC or two. I don't know yet.
After closed loop, the numbers do not always move quickly and occasionally seem to stall at 999 or 000. A very small movement of the throttle gets the voltage nambers moving up and down again.
The happy side effect is that the idle A/F numbers seem believable now. Before I was seeing very lean.