H22a Turbo Crank signal fluctuating?

[ty_93]

Hi guys ive got a weird one for you. I have an H22a turbo and during the dyno tune we ran into an issue when under full throttle. On the datalog within 1/100th of a second the crank signal (rpm signal) would fluctuate up to a couple hundred up and down several times. This in turn, would throw injector duty cycles all over and make it tough to tune as we would chase it. It produced torque numbers on the dyno all over because of it.

Now,
it is the jdm h22 with the crank sensor in the dizzy. It's a shielded wire from the original American harness location of the crank sensor (down at the oil pump) up to the dizzy. Is this fluctuation anything common or something you guys have run in to. I've considered swapping in an American oil pump and putting the crank sensor back down there so that there is not the variable of the timing belt being in between the crank and the distributor.

I'm really just at a loss. I can post a datalogg later tonight if I go for a cruise.

[ty_93]

If you look at the pull at 3minutes 4 seconds it is super easy to see the rpm's fluctuate horribly. I wonder if it isn't just a bad crank sensor in the dizzy.... need ur help guys.

[Spunkster]

This is not something we have seen. You may want to ask around various tuners, specifically ones that deal more with H22s to see if they have seen this before.