How to bleed a diesel bus engine

Being diesel fuel I doubt that is needed. The fuel does not degrade like petrol with ethanol.

Drain the fuel out and flush the fuel lines and the filter. Failure to purge the unleaded fuel from the system can destroy the engine due to severe pre ignition.

no country stated (we are USA forum) we dont have 8pc1 here.
no year stated
no car stated (or truck, light , heavy or bus)
just and engine block,,, force us to look up all cars with that engine. (seems not possible)

not only that, its a diesel (it has no spark)
is this a diesel injection pump question????????
how to time that?
we cant guess any of this.
my guess you are asking for someone else and have no facts to offer, per above.
my guess.

air bleeds are on the filter housing and on the fuel pump
If it has individual fuel lines to the injectors the loosen the injector nut to each injector and wind the motor over until you get drips at the nut. re-tighten the nuts and it should start

The air needs carefully bleeding from the whole fuel system. Seehttps://uk.answers.yahoo.com/question/index?qid=20090127103717AAaZvbX

it all depends on how much diesel remained in the tank before the gasoline was added, and how new and sophisticated the diesel engine is. In a 2007 or newer clean diesel engine, any amount of gasoline will probably damage the sensitive emissions control components (DPF, OxyCat and SCR) and system. In older engines with much less sophisticated and "touchy" emissions systems, a lightly diluted (say 90 percent diesel/10 percent gasoline) mix would probably pass through with little or no detriment. It might simply cause reduced engine power, perhaps a bit more noise, and possibly a sharp warning from the emissions sensors that detect something other than pure diesel exhaust. It's high concentrations of gasoline that spell real trouble. Whether a modern clean CRD diesel or an old indirect injection unit, burning straight gasoline or highly diluted diesel fuel will almost certainly result in catastrophic damage to the mighty diesel engine.

more than likely there's condensation and air built up in the system , youll need to crack the fuel lines open and bleed the system, just as if you were bleeding brakes, air in the fuel lines is a very common problem on diesels

ok its a diesel and disels come with a glow rod attachment you have to turn key on let sit for minute while rods heat back up and then start it

Well his first mistake was buying a Duramax Isuzu Diesel... But with that said, Diesel has a tendency to grow bacteria in the gas tank. Flush the gas tank and change the fluids in the engine and you should be fine. You may notice that some of the gaskets on the engine may leak now that they have dried up. they will either reseal themselfs in time or with thightening or you will have to replace the gasket. I don't think that will be the case after only a few years though.