Not every car that gets strapped down to our Chassis Dyno is there for a Performance Tune or Power Run. Its often forgotten that a Chassis Dyno is not only a Tuning Tool but also a very capable Diagnostics device.
In this instance our customer contacted us with the suspicion that their Toyota JZX110 car was “Pinging” or “Knocking” under load even with Chevron’s 94 Octane (AKI) fuel.
Our Dyno is setup with an Air Fuel Ratio (wideband) gauge as well as a Audible Knock Monitoring system and it didn’t take us long to confirm that the VVTi 1JZ-GTE was indeed suffering from “Knock” when load was increased much over a “cruise”.
It’s expected that the OEM engine management should be reacting to this condition and respond by retarding the ignition timing. We’re currently unsure why there is still audible knock, although our research shows that this isn’t an isolated case. It would seem that “Knock Control” is either not enabled by the OEM or its control is very limited.
The most cost effective solution is to install a “Piggy-Back” device such as the ECUMaster DET3 to tweak the AFR and add our own ignition retard until we are confident that the engine no longer “Knocks” under load.
For more information on “Knock” and its effects check out the article below: