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Discussion Starter #1
406HDi 2001 model, so earlier single plug ECU. RHY 110kw motor. Bosch fuel injection system.

Problems: Engine is quite lumpy when starting, only settles down to a smoothish idle after about a minute. Also not grunty like my other 406's, have to change earlier on hills.

Scanned with PP2000, no fault codes.
Live readings showed fuel pressure at idle was fluctuating a lot. Seemed to try to be at 290bar but dropped as low as 260 bar and jumped to 340bar. At 5000rpm it only gets to 800bar. Should be around 1300bar iirc?

Replaced fuel filter. No change in readings. Pump in tank is supplying a good volume of fuel, have not checked the pressure supply from it though. There is also no visible air in the fuel supply and the leak off test only produced the odd tiny bubble during the entire run.

Did leak off test. Ran motor for 3 mins at idle with 2 runs of 30 secs at 3500rpm in the 3mins. Leak off measured for injectors was 41mm-40mm-34mm-37mm so all good there. [I think the injectors should only leak off 10mm /min if good...??]

Changed FPR for known good one [off another 406 which I tested with PP2000 and pressures at idle were steady at 294bar]. No real change to fluctuations of diesel pressure at idle. Also no change to pressure at 5000rpm. Still maxing out at 800bar.

Changed common rail pressure sensor for one off same donor as FPR, no change in readings.

So it is looking like the HP pump is not performing..? Before I go down the road of replacing it, are there any knowledgeable folk out there with anything else I could check/change to fix the issue? Would be VERY grateful if I dont have to swap out the hp pump.. :p
 

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Discussion Starter #3
Will do! Forgot about that... :(

What pressure should the pump reach at 5000rpm? A couple of other forums [google search] seem to suggest around 1300bar but have found other conflicting advice so not sure.
 

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Max rail pressure is approx 1300 bar unless remapped and at idle it's around 400-500 bar. If you have diagbox it shows expected figures

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Discussion Starter #5
Update.

Decided to check live readings on some of my fleet of 406's [have far too many :eek:] that run well to confirm what outputs they have wrt pressures at idle and full throttle.. came up with 290-300bar at idle and 1320-1350bar at full power/4500rpm while being driven. Simply revving the engine to 5000rpm while parked- the pressure maxes at 800bar.

Back to problem car... after the above I had a dig around in the engine ecu diagnostic of PP2000. Went to the manual settings section and looked at the injector option. Found that the injectors were loaded in there as not re-centred. Checked the markings on the injectors and they were labelled Y. Changed the injectors to "injector re-centered reclassified 2/B/Y''. Started the car and problem solved. Idle pressure steadyish at 290bar, full throttle on the road 1320bar and idling straight after starting cold is smooth and at 800rpm. Power on the motor is vastly improved. Pulls like all the others now. Happy.. :D
 

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Looks like 406 has lower idle pressures than 307. (No I was wrong I was thinking of Delphi on my DS5) 300 Bar is correct idle pressure

The lower pressure on free revving is due to lower boost level so injection map only demands lower rail pressure and injected fuel qty via smoke map.

Happy to post 307 rail pressure map if it's any good to you (Added to Post)

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Discussion Starter #7
Cheers! Is the map for the 90hdi or the 110? Reason is I have a 307 90hdi that is remarkably underpowered and seriously needs a remap/addition of intercooler/change of turbo etc.. have not yet got round to investigating what I can do to give it more get up and go.
 
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