for one almost anything sprayed down a diesels intake can burn, hence rev the engine up, w/o any type of governor.
i removed the intake, had my shop chem clean it, took 24hrs to do. carefully cleaned the intake runners in head, 1- only clean a runner if that valve is closed, i think a few months ago lisa did this, had a load of soot end up in 1 or more cylinders, she couldnt turn engine over(by hand), because of this(letting an open valve let soot into cyl(s)), she had to pull the head. clean intake runners, and with valve still closed!, take a vac and get as much of that stuff out as you can. new intake gasket, probably need a new egr upper gasket as well, and its pretty good. to complete the job, i had my head off, fashioned an egr block off blank/plate, and should have no-0- recirculation in the intake now. theres a couple of places you can put a block off plate, i put mine on the exhaust manifold, before,@first flex pipe, for this place head needs to come off, engine is built just for that, so you cannt by-pass emissions. or another good place, the 1st flex pipe, going into the cooler, before the cooler.