Fuel injection timing on a 3406-E or C15\C16 Cat

The injector fires when the ECM tells it to not when the Cam tells it to so another words the injector is travelling through its stroke long before the ECM tells it to fire. the PW will control the duration of injection which will never be as much as the cam can actually deliver.

To look at it another way the cam may travel 10 or 15% or even more % before the ECM takes part and depending on Rack travel & PW as to what % it continues to inject. Under full noise and full load you might find depending on the Engine rating that you are only using 30, 40, 50, 60% of the mechanical cam.

If you consider the injector plunger movement it is stop start.. at both ends of its travel. It cant instantly build internal pressure and cant miraculously travel its full lift at a constant velocity so it will start slowly and accelerate to its max velocity and then slow to a stop and then return to its rest position. Having the Plunger in motion prior to the ECM playing its roll will reduce the time in ms for it to reach a pressure internally to be able to lift the needle to start injection.

 

Can a person advance the cam gear a tooth on a 5ek,6nz or a 7cz and gain anything that way Far_call

 

Will sure sound good .... Dunno if helps never dyno'd ....2ws and later gotta unplug crank sensor.....

 

The Timing wheel is integrated into the Camshaft Gear and as such if you alter the timing by way of advancing or retarding the Camshaft hear you will also alter the Intake and exhaust timing.
On the older 5ek Types you only had one engine speed/timing sensor but with all later engines you have two so you have the added problem of the two coming out of sync if you try and advance the Cam gear.

This is all simply done in the ECM Tables and that's what the ECM is for. Sadly there isn't a lot of people who can manipulate these tables with a degree of professionalism required. Lots of people say they can but in my experiences there is only a few people with a small amount of knowledge that they get by with. When it comes to the nitty gritty they all seem to fall over.

 

The injector lobe is only to add lots of pressure to injector. It multiplies the 90 to 100 psi from fuel pump to thousands of psi. Computer controls the rest. Based on throttle position engine position and speed . Plus many more.

 

You're talking over 99% of the peoples head Greg LOL

To put it in simple terms the the injector body is full of fuel all the time and has free fuel flow to the fuel rail no matter where the plunger is traveling in the barrel of the injector in relationship to the cam lobe. The electronic solenoid controls a door that traps the fuel in the injector body. Once the fuel is trapped it is only a matter of milliseconds before the pressure rises high enough to pop the tip open mechanically.

Altering the flash file by adding timing in the timing tables changes the activation of the solenoid. This changes when the door closes to the fuel rail and the following pressure rise internally in the injector body to open the tip.

Most people think the solenoid fires the injector. The solenoid closes the door to keep the fuel from escaping the injector body back into the fuel rail in the cylinder head that is its only job in layman terms. Fuel travels in both directions from the injector body to the fuel rail this is what most people never understand.

 

The milliseconds you mentioned to raise the pressure Kurt high enough to pop the tip open is proportional to the plunger velocity and degree of Crankshaft rotation matched to the Camshaft Ramp rate and Rocker Ratio ramping along with Engine RPM influencing the plunger velocity altering the Milliseconds to which it needs to open the door. When plotted correctly the ECM gives you the ability to utilise this rise in plunger Velocity by way of altering the timing at any given RPM to the degrees of Crank rotation to maximise Fuel burn, Horse Power and timing over many varying combinations of Rpm and Boost.
Something you cant do with any Mechanical setup.

 

OMG...........you did that on purpose!!!!!! ROFLMAO

 

Far call do you know and or have mutch to do with neil at advanced diesel??