Ive got a problem in a Single butterfly twin turbo V6. It misfires at certain RPM`s and it sounds just like a coil that cannot keep up under boost.
The misfire is always at the same RPM and repeatable on run after run on the dyno. The misfire would occur ot 0.2bar boost at 3500Rpm and again at 0.6bar at 4200Rpm.
This engine setup with the same coils have produced 700+ WHp at 1,4bar boost with no misfiring.
This problem showed up after an engine rebuild.
What ive checked.....
Changed ECU
Changed Igniters
Checked wiring from ECU to Igniters
Checked wiring from Igniters to Coils
Logged Coil power supply at 200Hz to see of coil power dipped.
Earthed Coils to the head with separate wiring
Earthed Coils and ECU directly to Cyl Head and Battery negative ( Tappet covers ceramic coated)
Changed all 6 coils
Changed all the spark plugs
Gapped plugs down to 0.4mm
Checked mixtures,
Checked MAP sensor at 50Hz for fluctuating reading
Disable Accel Enrich/Enleanment
Disable Decel Enrich/enleanment
Checked injectors for open circuit errors and short circuit errors.
Injectors Flow tested before engine build
Checked wastegates to make sure they open simultaniously
Changed Crank Sensor (no errors on the ECU whatsoever in any case)
What could this be? Could it be mechanical?
Could the ECU maybe not trigger errors under cerrtain cicumstances?