Just something for your friend, and perhaps you, to think about: at 4000 RPM, with a 4000 uS pulse width, your injectors are now open for a total of 96 crank angle degrees. I noticed that there was also mention of 4500 RPM...that same pulse width at 4500 now makes the injector-on degrees 108 at 4000uS. IIRC, peak cylinder pressure should occur at about 20-25 degrees after top center. leaving out ignition delay, rate of burn, cetane numbers etc for simplicity's sake...for peak pressure to occur anywhere near that point, baring all the other variables, you would have to set your timing advance at approximately 54 degrees! Now you are within the realm of injecting fuel when there is not sufficient heat to ignite it, you are most definitely hitting the cylinder walls with raw diesel, and lastly you're making your engine fight itself to make any power at all. If you were to pull the pulse width back to a more acceptable 3000-3250 pulse, you can now run timing that is WAY more sane, and actually make MORE power. :thumb:
