by bigBADbenny » Sun Mar 16, 2025 12:21 pm
You can get to the avcs failure mode by first testing the OCV’s in place.
Start with a cold engine, *all* accessories off, key on, engine off, *reset ecu*, key off, key on engine off, press rear defrost switch (option to log on rear defrost must be enabled in btssm or romraider logger software, engine on and allow the engine to idle with nil haptic control input until fully warmed up.
Open the log in eg MLVHD and plot VVT angles vs eg rpm & coolant temp. Does avcs attempt recalibration at 65’C?.
After the engine is fully warmed up go for a 20minute drive and include very steady freeway cruise eg using cruise control.
Does VVT activate, does VVT sync?
Let’s say there’s no VVT sync, no VVT angle.
You can put the car on hoist or stands, remove the engine undercover and log the idling engine whilst pulling the ocv harness plugs and individually powering each ocv in turn with a 5volt power bank positive and negative or same from a 9 volt battery.
In the datalog, does the VVT angle go to max on external power?
This test isolates the avcs fault to either the OCV or the OCV harness or the ecu.