What has to happen for a 6.0 to start




For a 6.0 to start a lot of things have to happen at nearly the same time. The exact order I really don't know, I have never really read anything that says exactly what has to happen in what order.
So this is just going to be a general list. Kind of a logical progression of events.


COMPRESSION:


One of the first things that has to happen is good compression. Compression heats the air to a point where the air/fuel mixture will ignite, in a diesel this is the only thing that ignites the diesel/air mix.
For this to occur you have to have a healthy cylinder and it's components. Good rings and valve train
working properly. You also have to have the piston moving in the cylinder a suficent number of times to generate this heat. 100 to 150 RPM is generally acceptable.


INJECTION:


On a 6.0 the injection event is complicated a number of things have to take place in a proper order and amount. The injectors are electronicly controlled; internal parts are moved by the hiph pressure oil system; fuel constantly surrounds the injector and flows into open ports in the injector body. Fuel pressure is maintained only by the fuel pump and it's regulator. 45 psi. Min. 55 to 60 preferred.


ELECTRONIC CONTROL;


A computer controlled diesel starts up on default settings until the sensors have time to send signals to the PCM. In the case of the PCM & FICM these are the Cam And Crank sensors. The PCM uses a comparison of the signals to determine the relative location of the crank and pistons once determined you have sync Next the PCM and FICM talk to each other and establish SYNC, The PCM then tells the FICM to pulse [fire] the injectors when it sees a min of 500 PSI pressure from the ICP.


HYDRAULICS:


The Low pressure oil pump feeds the HPOP resivoir with oil and the HPOP increases the pressure to 4000 PSI max. 500 min. The high pressure oil feeds the oil rails and the injectors. The spool valves open and allow oil onto the top of the intensifyer piston which in turn squeezes the diesel incresing it's pressure until it overcomes the spring pressure holding the pintle rod down lifting it off its tapered seat allowing diesel to squirt out of the six nozzles in a fine mist.




FUEL:


Last but not least is fuel it is deliverd by the fuel pump in the HFCM mounted on the frame rail under the drivers door. Pressure is regulated at the upper fuel filter which has a return line for excess fuel to the tank. Once fuel leaves the filter and goes to the drilled passages [rails] in the heads there is no other control over pressure or volume. Fuel flows into the injector thru open ports on each injector.


For this reason fuel pressure/flow is critical, min 45 psi 50 to 60 better. There is a blue spring kit available if your pressuers drop.

 

great list Danny.

Don't forget the "Air" requirement, but not much complication there - just need to keep an eye on the filter minder (even though many don't like it, it works).

 

Thks I should have used a smaller font I ran out of room in my word proceesors page.
But then I wouldn't be able to see what I wrote. Getting really blind here.

 

You say 100-150 RPM, I was always told that under 150 the PCM wont tell the FICM to fire injectors. It must see that along with ICP pressure and Cam/Crank sync to fire injectors.


Also as the temps get lower heading into winter you have to remember glow plugs.

 

While I have never seen documentation to that affect I can well believee it.
I based that on it generally takes that rpm range to generate enough compression to ignite the air fuel mix. A healthy cylinder it is around 100 RPM a slightly weaker cylinder it can take 150 or more RPM.

 

Ford states 100 rpm minimum, but Techs have confirmed that the 150 rpm is a "real world" value.