Theres more than that in the standard for the fuel.... the initial movement for the sulfur reduction came about from smog and particulate matter reduction.
Sulfur dioxide (SO2) - Air quality fact sheet which is an australian document I agree but it covers the pertinant points.. If theres no sulphur...... :)
theres also something in the EPA regs (which you can use as a substitute for some of the aussie ones com build time) and they have a limit on SOX's and since that same reg is also substitutable for EURO X over here....... (just dont try swinging a new vehicle into europe on that loop)
But heres a more interesting link for you....
http://www.environment.gov.au/atmosp...ubs/paper5.pdf
and heres a quote from the foreword...
cutting through the Chaff. euro 1 can pretty much be passed on any old fuel if your engine is running well enough and is actually capable of passing the standard in the first place. (as in no, your late 1800' hitnmiss governed hot bulb engine is not going to pass) from Euro II on the fuel standard is included in the mix and is when low sulphur diesel becomes a specified standard. Nutshelling that. the reduction in sulphur content is enough to drop the particulate matter from a diesel into the relms of passing providing the engines in good trim.
the pic showing the plate location and the page with the data sheet were the first ones on google.
according to the aus Isuzu website the engine was available in the NPR range up to 95 so its good for EURO I on that alone, of course now that Im looking for it all Im finding is industrial application data (which is tier II)
this link is flakey, but allegedly lists the american emission compliances for all isuzu engines
Isuzu - PDF documents (note the seps also refer to the 4bd1 as the qd-100)
the engine as the qd-100 (and the 4bd-1) is alternatively listed as being and then not being MSHA tier II compliant (may be because of application/condition of engine)which is another altogether more confusing thing which may or may not be the same as euro II, III or some wierd hybrid of the 2 because it doesnt deal with onroad conditions and is not directly compatible...
in theory....
you should be able to claim compliance on the build date of the engine.
Isuzu Diesel Engines - Frequently Asked Questions (FAQs)
buried in there is how to decipher the build date and later has an example of the complaince data plate.
have fun.