Injector Dynamics Dead Times and Calibration

[jun1or]

I'm well educated on injector dynamics, new to tuning them.
I am having issues with idle, consistent fueling, and primarily cold start. My over run hangs lean and doesn't have a clean cutoff. My cold start seems to be very lean. This is with stock fuel injectors, stock injector calibrations, stock fuel pressure and no other known issues. All this points to a latency issue, caused by a poor wiring job, and more pronounced on cranking.

Look here for some data log graphs -> http://www.romraider.com/forum/viewtopi ... 15&t=12318

Thanks for your input jun1or.

I assume this is 91/93 fuel, not e85?

Can you overlay wideband a/f input onto that datalog/chart? If so please do it. You'll need to ensure your wideband is preheated (give it 10 seconds or so) and it's wired up around the starter, meaning it stays on during cranking cycle. I had to do this to troubleshoot cold start issues in a tune before. (that was on e85 in Wisconsin weather, not fun. Had to wait for it to cool down too, otherwise it would fire right up, just like your issue from what it sounds like)

[pyro6314]

Yes its on 91 fuel for now. Unfortunately it doesn't look like I waited for the wideband to heat up and there is no useful data in my logs. The point is, most everything is stock minus some changes to the intake, turbo and block. Subaru TGV deletes and port matching; possible lack of turbulence for air/fuel mixing. Prior Subaru models have never had an issue starting without TGVs and there are very few cases where removal has needed tuning to start perfect. The rest of the air intake shouldn't matter as no air is metered on start up.

I have obvious electrical issues with power to the ecu and therefore I assume, especially on cranking, the injectors just aren't opening enough for cold start. I'd rather not tune around a serious electrical issue...which is why the harness is now stripped out the car. I pray all this work will cure the issue and I can finally install my 1000cc injectors and get off wastegate boost. I plan on tuning the latency curve with an adjustable power supply at idle, open loop and compensations off, then trim the curve up/down based on the overrun cutoff.