Diesel injection requires minimum 3000PSI or so. Today common rail turbo diesel injectors operate upwards of 20,000PSI.

I've had similar issues with my fourstoke conversions. Operating temperature causes the variation in ignition timing. I have my theories, but haven't tried anything yet. Mine have been operating on standard fuel mixes. Preignition or detonation doesn't seem to be much of an issue with two stroke model diesels but the fourstrokes behave differently.

Greg