Problem with fuel pressure on 3.0 TDI

Hi all,

I am the happy owner of an Audi A4 B7 3.0 TDI 204 (BKN) of 2005.
It is a pleasure to drive it with a simple remap.
But I want more power and I am limited with fuel pressure.

With original map, fuel pressure mounts at 1600 bar, all is OK.


And with my remap, I can't touch 1600 bar like original map (I ask 1600 bar a little earlier).


I must verify but I think my HPFP is a CP3S3/R90.
What is the problem and how can I touch 1800 bar ?

Thank you

Filter is ok? Presupply pumps? With 80mg, that pump should be able to keep 1600+ bar in higher engine speeds without much of a problem. Hannu (hatemi) and i both got raildrop around 110mg in higher rpm. I have CP3 L110 but also 2 more mouths to feed 4.2tdi.

we need to see injection time not IQ

Stock fueling systen can make 1800bar at almost 100mg without any trouble if its in good condition. Check your fuel filter, tank pump and i they are ok then the fuel return line presure regultor.

Lähetetty minun PLK-L01 laitteesta Tapatalkilla

Thank you all for your answers.

Kerma, injection time is 920ms at 4000rpm.

For fuel filter, I must verify it because I didn't change it since at least 2 years and 25000 km... Shame on me... I will start by changing it.

For tank fuel, how can I verify it ?

You can put a pressure gauge in the fuel line between tank an filter. You should have ariund 0.5bar at iddle. With 110mg at 4000 rpm mine dropped to 0

Lähetetty minun PLK-L01 laitteesta Tapatalkilla

Perhaps with aditional fuel feed pump could be the way to go.With 4 bar feed pressure CP3 pump stock can do 2000bar.

Even without 4 bar feed pressure it can do 2000 bar. Im running mine with 2100bar. Everything was fine untill 110mg. Now i will install 044 pump after filter with 4bar regulator to boost up supply pressure, hopefully this helps. Fca and gearpump mod didnt gave any improvement.