WT91 wrote:I do see in my datalogs that there are some very strange spark advance numbers. Like 5000 degrees advanced at 2000rpm 45 map. Or 11000 advanced at 6800 RPM, which I have never revved the engine up to. I suspected the distributor, so I replaced everything in it. New magnetic pickup, new rotor, new cap. What could cause this?
I saw something similar on my '88 several years ago. Random rpm spikes in crazy rpm numbers.
Intermittent, like 1 sample out of hundreds, but they were there. Truck never acted strange or stalled though.
I replaced the wiring from ignition module to pickup coil w/ twisted pair wire, and never saw it again.
I'd guess it was picking up interference from something?
You can make your own twisted pair it isn't hard, but I already had a bunch laying around.