common rail trucks

[TCDiesel]

The Injectors and Lift (Factory) lift system shut down when Ignition is Turn off,Their is residual fuel in lines, Pump, system,The Pump gear will continue to turn and Produce Pressure, since the solenoid valve is shut this creates a spike in the system of incredible force. .

 

[TCDiesel]

Here is a Picture of 3gen Injector.

 

[JasonCzerak]

The Injectors and Lift (Factory) lift system shut down when Ignition is Turn off,Their is residual fuel in lines, Pump, system,The Pump gear will continue to turn and Produce Pressure, since the solenoid valve is shut this creates a spike in the system of incredible force. .

Ummm, wait... what?



If your in a manual, and you leave it in gear while shutting the motor down and rolling. Yes. But who does that? little extra stress on parts right? maybe some rubber on the ground too.



If your in an auto, maybe as well, you think there is enough force at 5mph to keep turning the crank though the torque converter?



The main safety factor of shutting down early. And the lack of the cool down time on the turbo, and I'm sure it's illegal to shut down while in motion. Unless your a extreem "greenie" the majority doesn't do this.

 

[betterthanstock]

Yeah, I think the FCA opens up completely (highest pressure) when power is off, but not sure...

That means, with injectors closed, all that pressure gets relieved via the rail pressure relief valve. Not that bad if you still have one in working order, but for those who think they don't need one, and took it out, bad news, excessive psi= cracked injectors, etc... .

As for the lack of cool down on turbo, that is not true. The oil keeps on circulating, and so does cold outside air thru the engine. If anything, it cools excessively.

 

[JasonCzerak]

How does oil keep circulating if the motor is off? mechanical oil pump right? This isn't an audi where they have a supplemental oil pump to cool the turbo when you shut down.



As far as on shutdown, there is a large spike. The way my Diprocol gauge is wired I don't see it on it, but on my TST box, if you shut down with it on the RP gauge you can see 27,000 and it comes right down to 0 in a few seconds.

 

[betterthanstock]

How does oil keep circulating if the motor is off? mechanical oil pump right? .

I thought he was talking about turning off the ignition key while coasting down hill, in gear, with stickshift, so engine keeps turning. That's why the fuel pump pressure would remain high, and the relief valve comes into play.



Coasting with ignition on, the FCA shuts off fuel to CP3, so there is no significant spike.

 

[steved]

I want to see how someone drives a manual and feathers the fuel on/off??



You're either into it to accel or off it to shift... I'd get run over if I drove any differently... :-laf



steved

 

[JasonCzerak]

I thought he was talking about turning off the ignition key while coasting down hill, in gear, with stickshift, so engine keeps turning. That's why the fuel pump pressure would remain high, and the relief valve comes into play.



Coasting with ignition on, the FCA shuts off fuel to CP3, so there is no significant spike.

People actually do that? Shut the motor off when "coasting"? That is the most asinine thing I have ever heard. All that to save $0. 02 in fuel?



When I just let off the throttle, rail pressure is about 8,000.



On the 7. 3 the motor goes dead quite when you coast.

 

[Cattletrkr]

I'll shut mine off when rolling to a stop quite often, but never w/o the cluth pedal depressed.

EDIT: When parking at home, not on the road.

 

[betterthanstock]

People actually do that? Shut the motor off when "coasting"? That is the most asinine thing I have ever heard. All that to save $0. 02 in fuel?

When I just let off the throttle, rail pressure is about 8,000.

On the 7. 3 the motor goes dead quite when you coast.

I was referring to post 34 above, where he says

"1st, and foremost, Never shut down vehicle while it is in Motion, This Very Important for Manual Owners"



I have shut it down once, going downhill on curves at 25 mph, I put it in neutral and then shut it off. I wanted to feel what it would be like if the engine were to suddenly die, or if I lost the belt. I almost ended up into the ditch. The steering gets super heavy, and the brakes do too after 2-3 applications. I then immediately put it in gear and let out the clutch, which turned over the engine. I may have taken an extra second or two before I turned the key back to run. That's when the pressure spikes, before the FCA starts to regulate it, as it does when the ECU is normally on.

The relief valve should take care of that, unless you eliminated it, like some people have.