MJLJ Frequently Asked Questions

Does the MJLJ have knock control?

Q: 'I'm running a boosted A-Series mini. Does the MJLJ support knock control?'

A: Knock sensing is a sophisticated problem to solve, as evidenced by companies that offer comprehensive knock sensing solutions like SafeGuard.

There is some good information on the Megasquirt website discussing knock sensing using components sourced from General Motors: [1].

So the short answer is that the current version of the MJLJ firmware does not support knock control. However, the firmware could be modified to accept an input from a module like the GM unit described above, and then act upon it, typically by retarding the timing in some fashion.

If you read the Megasquirt documentation you will see that the GM module and sensor is tuned a specific way, likely optimized to work well on the GM engines it was designed to fit on.

The question is, does your boosted A-Series knock signature sound like the GM's V8? Is it close, or way off? Is it similar enough to realize *some* benefit? Obviously the same goes for all engines. I'm running a turbocharged Toyota 4AG that would obviously benefit from knock control; you bet I'm interested in such a thing.

So after that long answer- :) There will be knock control of some sort for either this version of MJLJ or an upcoming version.