Peugeot Common Rail High Pressure pump

From my Haynes Manual:

Pump type: Bosch CP1 Rotation: Clockwise viewed from sprocket end. Pressure: 200 - 1350 bar (according to engine speed)

"The high pressure pump is mounted on the engine in the position normally occupied by the conventional distributor fuel injection pump. The pump is driven at half engine speed by the timing belt and is lubricated by the fuel which it pumps.

The fuel lift pump forces the fuel into the high pressure pump chamber, via a safety valve.

The high pressure pump consists of three radially mounted pistons and cylinders. The pistons are operated by an eccentric cam mounted on the pump drive spindle. As a piston moves down, fuel enters the cylinder through an inlet valve. When the piston reaches bottom dead centre (BDC), the inlet valve closes, and as the piston moves back up the cylinder, the fuel is compressed. When the pressure in the cylinder reaches the pressure in the accumulator rail, an outlet valve opens, and fuel is forced into the accumulator rail. When the piston reaches top dead centre (TDC), the outlet valve closes, due to the pressure drop, and the pumping cycle is repeated. The use of multiple cylinders provides a steady flow of fuel, minimising pulses and pressure fluctuations.

As the pump needs to be able to supply sufficient fuel under full load conditions, it will supply excess fuel during idle and part load conditions. This excess fuel is returned from the high pressure circuit to the low pressure circuit (to the tank) via the pressure control valve.

The pump incorporates a facility to effectively switch off one of the cylinders to improve efficiency and reduce fuel consumption when maximum pumping capacity is not required. When this facility is operated, a solenoid operated needle holds the inlet valve in the relevant cylinder open during the delivery stroke, preventing the fuel from being compressed."

They also stress the dangers of working with a high pressure fuel system and state that, due to the very close tolerances involved in manufacture, no attempt should be made to dismantle the pump. They also point out that no individual parts are available, only a complete replacement pump.

Hope this helps.

Hi,

Pretty true, but I wanna add some info : Engine control unit : Bosch EDC-15 ; The third piston on the hi-pressure pump can be electrically deactivated, true, first when it's on partial or low load (i.e idle, hence the low pressure (BTW I've heard of 600 bars instead of 200, but not sure), *but* the third piston is deactivated when the fuel temperature in rail reaches

70°C (158°F). The high pressure pump takes its power from the engine, we all agree about that. The power required is about 9kW (12HP), IIRC.

HTH, G.T snipped-for-privacy@worldonline.fr

205 Diesel & turbo-Diesel :

Hi,

Thanks for the information!

My 406 HDI has some starting problems.

About 2 weeks ago it refused to start (but turned the starter motor ok), I changed the glow plugs, diesel filer, cleaned all electrical connectors in the engine bay, check all fuses, replaced the pressure regulator on the back of the pump, cleaned the valve on top of the pump, checked the return valve on the supply to the high pressure pump, checked the fuel supply from the lift pump and cleaned the connector on top of it, checked the fuel flow from the high pressure pump to the rail.

I still have the same problem!!!!!!!!!!!!.

Normally when I want to start the car with a cold engine, I just turn the key and the car starts after 2-3 seconds, but now the car needs a lot longer time before it fires, about 5-6 seconds with the starter running, sometimes the car will not start at all.

But the weird thing is, when the engine then starts it runs normally, responds to the accelerator normally.

I though about replacing the pressure sensor on the rail, or event the 3rd valve on top of the pump.

Will this help?

What can I do to solve my problem?, where can the problem bee?

TIH

and high temp can be reached when the scavenge pump is going down

hmmm had this prob before check the earths to the engine also check the earth to the camshaft sensor had a bad earth to this once and it gave this symptom

Hi,

"and high temp can be reached when the scavenge pump is going down"

What do yoy meen?

TIH

if the scavenge pump (in the fuel tank) is losing pressure then the main injection pump works harder to get the fuel moving through more strain means increasede line pressure which pushes the fuel temp up

ok,

What should i do, then?

TIH

pressure from scavenge pump should be minimum of 2 to 2.5 bars check this if possible also check earth to camshaft sensor (sure i posted this earlier,if not here then someone somewhere is scratching their head)

Hi Again,

Could it be the valve clearances that need to be adjusted?

Will incorrect adjustment give start problems?

The 2,0 HDI has now covered 200.000 KM, without any other problems.

TIH

Hydraulic tappets.

Hi,

I checked again, and the fuel lift pump delivers a very constant flow of fuel to the high pressure pump. I check the ground connections to the ECU and the engine, and found no problems. I verified the adjusted the camshaft sensor, and found nothing wrong.

I checked the flow of fuel from the high pressure pump to the Rail it self, by unmounting the pipe from the rail. The flow of fuel from high pressure pump was constant, but significant slower then the flow from the lift pumps.

Is that correct? Or do I have an indicator that something is wrong with my pressure pump?

How does the pressure sensor on the rail and the pressure regulator on the high pressure pump work together? Has anybody had problems with these to sensors?

I need some advice, to continue my troubleshooting.

TIH

the pressure regulator is simply that a pressure regulator its is controlled by the ecu