volvo 2003 yet again

[mldpt]

anybody know where i can get an exploded view of the 2003 engine, I want to know how it all works, I know the basics of the desiel engine but would like to understand how the fuel control is handled by the throttle. I asume the increase in throttle opening must increase the fuel to the injectors or does it somehow speed up the cam that the pumps work off. And how does the cold start mechanisim work. I hope somebody out there can help, somebody must know how they opperate, because somebody built them.
Mike. www.sailingforfun.co.uk
regards Mike.

 

[Juggler7823]

A simple explanation:
Opening the throttle opens the fuel rack on the high pressure pump, more fuel enters the cylinders and the engine speeds up. The cold start moves the fuel rack fully open to admit excess fuel. The procedure is: increase throttle to at least half, pull the stop handle, yes the stop handle, start engine, drop revs.
Roy

LOM

 

[mldpt]

hi roy.
thanks but I understand the basics, on the v/p 2000 series each cylinder has its own pump and I cannot see where the rack opperates, to increase the fuel, I would have thought the individual pumps would deliver the same amount of fuel for each revolution of the camshaft that drives it, the timing is set by increasing and drecreasing the pump pistons up and down movement by shimming the pump body to or away from the cam driving, but how does the rack increase the fuel flow to the injectors, I always assumed that it worked on the same principle as the petrol engne, increase the air flow increases the petrol drawn into the cylinder hence bigger bang and the faster you go. (old carb type engine) I'm old too
Mike

 

[stubate]

i think you will find that the rack runs across all three pumps, the timing is done by the gear drive from the crankshaft and that is what sets the pumps up in relation to the piston position. as the rack moves it turns the pinions on the pumps and there is a peg from the pinion to a spiral slot in the pump that makes it increase or decrease.
the rack is driven by the governor which always starts in the full open position, as soon as the engine fires the governor weights are activated which then shut the rack to the position determined by the throttle. cold start is done by opening the rack to a further position so that more fuel is allowed in, this is done on this particular engine by pulling the stop lever whilst in open throttle position as roy has posted.

 

[stubate]

oh i forgot, the shimming that you refer to is something i dont think is relevant, i have only ever seen it on cat diesels where the shims are used to make sure that each pump delivers equal amounts of fuel for a given throttle opening
s

 

[Juggler7823]

I am somewhat surprised by your statement that shimming is unneccessary. I have worked on 4 differnt Volvo models and all had shimming on the pumps to allow correct metering of fuel to the injectors. The Volvo manuals give detailed procedures. The variation in the shims provided suggest that it is critical.
Roy

LOM

 

[andy_wilson]

Air and fuel supply

The only restriction on air supply is blockages in the air filter, and poor ventilation to the engine room.

Engine speed and power are determined by fuel metering.

 

[mldpt]

Istill dont know why, after having the injectors serviced by Boch having ground the valves and seats, and apparently inproving the compression considerably, so much so that the engine starts easily where as before it needed easystart, it now smokes more than before and deposits a film of unburnt diesel on the water, it starts and runs far better than before, it has done 4000 hours, has loads of power. Next job is to check the compression, I wish I had had the pistons out and checked the rings.
mike

 

[vyv_cox]

Roy,
Not something that ever needs to be done again, though?
Vyv