Two thoughts for this post. Wide Band O2 (WBO2) sensor and cam sensors.
First, is a WBO2 needed. Not necessarily. It is a good diagnostic tool and provides information on how good your engine tune is. You put together a reasonable timing/spark/ignition table to start - lets call this the timing table. The same with the VE (fuelling) table.
The VE table is the first table to be adjusted to suit so that you can get the engine fuelling requirement where it should be. This table is paramount to getting the correct air-fuel ratio. The VE table cell values are just a number that is used in the calculated fuel requirement. The higher the number the more fuel is to be injected - rich, the smaller cell value number, less fuel is injected.
The timing table is next to be calibrated. When you increase a cell value - advancing the timing, you are in essence leaning out the air-fuel mixture because the fuel has a longer time to "burn". Reducing the cell value - retarding the timing, essentially reduces the fuel "burn" time and causes a fuel rich air-fuel mixture.
There is a sweet spot where you want the maximum fuel burn "pulse" to meet with the engine pistons for optimum engine performance and efficiency. This is approximately 10 to 15 degrees after TDC. You want the full injected and ignition to be at a point before TDC so that the fuel burn "pulse" meets this requirement.
It's a back and forth effort to get to well balanced VE and timing tables.
Once this is done, you can calibrate the AFR (WBO2) table to suit.
Do you need to use the AFR table, no. You can, but well calibrated VE and timing tables are the basis for calibrating the AFR table, and as such, is all you need.
The VE and timing tables produce an immediate engine response whereas the AFR table is an after the fact sensor for the ECU in that the WBO2 sensor that provides the input to the ECU is in response to what the engine is doing. The WBO2 signal to the ECU is based on what has happened, not what is happening or going to happen.
Honda realized this and did not incorporate an O2 sensor in these older FI GWs, and when new, emissions were probably quite good and did meet the requirement of the day. A place to install an O2 sensor didn't help.
Something to consider.
Camshaft sensor(s). These along with the crankshaft sensor provide the ECU with signal(s) to ensure correct fuel and ignition for the engine.
The crankshaft sensor is predominantly for engine timing, whereas the camshaft sensor(s) are for fuel injection.
The camshaft sensor(s) are used to indicate to the ECU when a cylinder is at TDC for engine "phasing". You can operate an engine without a camshaft sensor, but the crankshaft signal as the only crank/cam indication only allows the ECU to guesstimate what to do. It has stood the test of time, but the engine does not operate as effectively and efficiently as it could. It will operate well for most normal vehicle applications, but it can be better. Enter the camshaft sensor.
Should you wish to have sequential fuel and ignition, you will need a crankshaft and camshaft sensor. If you wish to stay with a wasted spark and paired injector engine profile, you can still benefit from a camshaft sensor.
The '85/'86 FI GWs have two camshaft sensors for accurate fuel injection and engine operation. Honda has achieved a semi-sequential fuelling using these two sensors, the engine is more fuel efficient, starts extremely well.
These sensors indicate to the ECU when a cylinder TDC has occurred and when to inject fuel into the engine. The Gr (right) sensor controls fuel injection for cylinders 1 and 3, the Gl (left) sensor controls fuel injection for cylinders 2 and 4.
Once the ECU receives a signal from a camshaft sensor indicating a cylinder TDC, 4 signal pulses from the crankshaft sensor after the signal from the camshaft sensor and the ECU triggers the respective fuel injector(s).
Very sophisticated for the time, and not much has changed since.
Are the camshaft sensors beneficial for any FI conversion, yes, even if you do not use these for sequential applications. The more and more precise information that the ECU has to use, the better the engine operation and performance will be. Bottom line, install a camshaft sensor, or a sensor that will send a signal to the ECU at half crankshaft speed.
Do you need an O2 sensor, no, but it's a good engine tuning tool.
Do you need a camshaft sensor or a facsimile of such, no, but It will permit the ECU to better control the engine operation and performance.
Just my thoughts on the FI system components.
Cheers
