Tuning problems - s300 + irregular a/fs on dyno. Gurus pleas

[Lyle_57IAL]

Hey guys,

Some background info. Running a built d16z6 block d16y8 head, d15b7 dizzy, 92-95 looms with p28 s300 Ecu.

Fueled by twin walboros pumps on a full blown hanger, rc 750 cc injectors, aem fuel rail and reg. Running at aprox 18psi with 10 deg total timing, fuel pumps and noisy and average aprox 45psi of fuel pressure. Makes aprox 300whp. Ecu set in open loop.

Have a very annoying and concerning problem - after map is updated with all necessary settings - we do a power run with the car on the dyno. Every time running a different a/f ratio curve over the graph- somtimes rich and sometimes lean (starts to detonate). Every time a power run was done no changes were made to the Ecu but yet never a constant af mixture over the map.

Done a data log while on the dyno and the Ecu is changing th duration of the injector duty. Any reasons why it could be reacting this way ? Could this be a electronic issue with the Ecu or possible a hardware sensor the Ecu refers to etc?

My head is in a fuckhole black cloud and very worried. Will upload the dyno printouts of the power runs and data logs ASAP

I belive i could have a bad & dirty earth system due many aftermarket electronics.

Here are dyno printouts and datalogs. Keep in mine these are back to back power runs with no map changes. Strange to see the very noisy Rpm signal and also these issues made my boost levels initally jump from 18psi to 25psi without changing any solenoid figures.








Thanks you to everyone who could contribute

Lyle

[Spunkster]

Do you have a wideband wired into the ECU?

[Hondata]

Injector dead times look very low, but if you change these now you will need to retune.

I think the cause is at least partially from ECT compensation. In 'Water Temperature Compensation' set all the 168 degree values to 0%

However the main thing I see is that the rpm signal is all over the place. It would be worth trying another distributor to see if that fixes the signal.