Weird jump in injector pulsewidth at 5800rpm

[KarstenWilson]

I've been tuning my motor with some upgrades, it's a B18B1 NA build. New intake, and injectors. It's a race car, bought from another guy. The weird thing i'm trying to track down, is that on all my logs, even after i bought the car, and before i started trying to tune for the new parts, there is this jump in injector duty cycle/pulsewidth at 5800rpm. Watching how the log passes through the fuel table, it doesn't seem to explain the jump. I can't find any features that activate at 5800rpm, let alone ones that might effect the fuel injectors. Any ideas?

An example of the jump can be seen at 3:17 in the attached log.

Oh just fyi, my O2 sensor seems to be failing so i stopped until the one i have on order arrives... It was reading ok before, but a little rich, around 11.5-12.7, but now it's getting stuck and then erroring out...

Thanks!

Karsten Wilson

injector_jump.jpg

[Spunkster]

If you have the wideband hooked up so it is datalogged, then it is running VERY rich, or the sensor is faulty as it is reading in the 7's.

[KarstenWilson]

Yes it's definitely broken. I pulled on off my other racecar this morning, and it was 12.5 - 13.5 range for everything, except > 5800 where it adds the 20% fuel. I've got a new one on order!

I went ahead and tweaked the fuel tables to compensate, and it is much better, but I still don't understand why 5800 has such a steep cutoff. I mean even my fuel tables have data points at 5000 & 6000, so seems like it should be a more gradual change...

Thanks,

Karsten