int sl/python no parking light activity

Got onto the #4 injector on drivers side of motor tonight and was able to learn tach AND induce an over-rev shut-down. Using the injector for tach does requires a higher rpm level for a longer sustained duration in order to induce shut-down when compared to the Fortin INT-SL bypass tach output. The INT-SL tach induced shut-down much quicker and at a lower rpm for a much shorter duration. From this perspective, the INT-SL tach is superior. However as discussed previouly the INT-SL appears to have a delay during initial start-up that causes the starter to remain engaged longer than when using an injector. After realizing the approx rpm & duration levels required to induce shut-down for an injector, I went back and retested the wht and the ppl/blk wire on the ICM as possible tach sources. Both of these wires will eventually induce shut-down, however they required an even higher RPM for a longer duration than the injector. So for these collective reasons I will be staying with the injector as the source of my tach signal.

One more point of possible interest for future reference...

On this 2000 cavalier the wires that feed the injectors and the ICM are all located in the large plastic loomed harness that runs across the top of the engine block and than vert down the front of the engine. However there are multiple wires of the same color in that harness that match the injector colors. I was not able issolate which of the multiples was an injector wire without first unplugging the injector and tracing continuity back to the unplugged injector connector. With the injector plugged in, multiple wires(of the same color) would show continuity back to the plugged in injector connector. I am not sure why that is, but I can only assume that my meter was tracing through some other path and returning via the chassis. Getting to the injectors themselfs is a pain on this car, I eventually removed the air intack horn and the steel cover plate that sits over the injector rail. In the end removing those items was not that hard or time consumming and I should have done it soon because it made accessing the injectors much easier.