Part 12
Important note: On my ITB EFI set up, I am using a Pertronix Ignitor instead of the original contact points. The Pertronix Ignitor, which prior to the conversion used to trigger the factory CDI module to fire the ignition coil, is now serving as the crankshaft position sensor (CPS) for the ECU. In order to ensure a clean CPS signal the ECU uses a shielded single twisted pair cable with the shielding internally grounded to the ECU ground connections (which are connected to the ground terminals of the ECU power panel) and the CPS wire connected to pin#2 of the left EFI connector block.
In order to ensure a clean CPS signal from the Pertronix Ignitor in the distributor, a shielded single twisted pair (20 gauge) cable was used with a bullet connector to the Pertronix Ignitor signal wire (the black wire) at the distributor and the other end of the shielded single twisted pair cable was connected to pin#2 of the left EFI connector block. The shielding for this cable was grounded to the engine at the left camshaft chain cover.
Now more about tuning: This afternoon I made another 90 minute run in the hills with my PC running the TunerStudio app while connected to the ECU. I used the Auto Tune program to tune the VE table and made more adjustments to the acceleration enrichment to get better tip-in response when I whap the throttle from idle with no load.
Important note: from the online help for Auto Tune, it is suggested that you run Auto Tune with the acceleration enrichment active as you would while normally driving the car. So when I made changes to the acceleration enrichment parameters, the optimum value of a given cell in the VE table to achieve the target AFR could change, so I ran a pass of my hill course with Auto Tune running after each adjustment of the acceleration enrichment parameters.
Then once I was satisfied with the car's performance on the hill course, I saved (burned) the Auto Tune corrections to the ECU's non volatile memory and turned off the Auto Tune program and drove around town and on the freeway observing the car's performance while monitoring the TunerStudio gauge cluster.
This is an iterative process of making tuning adjustments and testing the resulting behavior of the car using as many driving situations as possible to ensure the best overall combination of driveability and performance. The following are screen shots of my current tune:
