P0087 Fuel Rail/System Pressure - Too Low

[Raiderv13]

Hi. At the beginning I am sorry for my language.
I have a problem with my car A4 B8.5 2015 2.0 TFSi, engine code CPMB. He have 91,300 kilometers mileage.
I did to him Stage 2 tuning, with exhaust customs 2,75', superior ic 550x230x65, ECS Turbo muffler. Car stayed tuning on Shell V-power fuel 100.octane.
https://drive.google.com/file/d/1XeK...ew?usp=sharing

I have a problem with fuel pressure. I do not know what it can be.. The car is moving very good. I don't see strange behavior while driving.
Recently I replaced HPFP to OEM parts, because sealant was used and the oil was mixed with the fuel.

You could see mine logs about fuel pressure? I did logs with low fuel pressure and high fuel pressure. Pay attention to low fuel pressure while full acceleration. I think works bad...
https://log.tunezilla.com/s/4j3KeHcV This is a free acceleration.
https://log.tunezilla.com/s/j6zKw6Fe This is a full acceleration pedal.


what do you think?

[Smac770]

Must be nice to have a G410 sensor and actual low pressure line data.

It's curious that you have IDE00188 for high actual. My CAEx has IDE00201 for high specified, but no IDE00188. I have IDE00589, "fuel pressure", instead.

Yes, it would seem the electrical pump is not able to keep up with the fuel demand at full engine load. This has nothing to do with the HPFP. But who knows if that's a problem. If you're not getting a DTC, not having an operational issue. You didn't normalize the high and low columns to a common unit. So long as the high line actual is staying with the specified, the low line dropping off is not an issue. But to fix it, you'd need a better in-tank pump, or maybe a different controller.

You didn't log IDE01893, fuel pump:specified value, which is likely the duty cycle being sent from the ECM to the in-tank fuel pump controller? Is it capping out?

[Raiderv13]

Thanks for the answer bro.
I use VCDS ver 19.6.2 in PL version. "Yes, it would seem the electrical pump is not able to keep up with the fuel demand at full engine load. " I think so too... but tuner ensured me the fuel pump in-tank is sufficient. They did it same car, same engine code CPMB, with K04-064 turbo, to 365hp on oem fuel pump and was well. I do not understand that... but I getting a DTC code several times. The problem is within 2500rpm-3000rpm while free acceleration then He lit up CheckEngine and P0087 code. Later I will log IDE01893, fuel pump:specified value. Sorry, I forgot about that. There's a possibility damaged sensor G410? I nothing replaced none fuel sensors... Where can i find him under the hood of the car? Can you give me a sensor number? I will look for on diagram CarProg 2.
What do you think about filter fuel pump?

[Smac770]

P0087 is fuel rail pressure too low, but is about the high pressure system. Fuel system pressure too low for the low pressure system is P008A, according to the Quick Ref Spec Book.
And we see that in your "free acceleration" chart, but not in your "full acceleration" chart. The actual and specified are hanging at 10 MPa but then the actual starts falling off towards 5 MPa. Suddenly, it catches back up at 15 MPa.
So sure, we see the LP falling off some and not keeping up with specified, but that huge gap in the HP is your DTC problem. But what is the cause? Why is it short and then suddenly catches up; why is there not any gap on the WOT run?

I believe IDE01893 to be about the duty cycle to the in-tank pump controller, but I cannot guarantee that. I see it in mid-40s idling to mid-50s WOT.
Trying to find something indicative of the HPFP control, best I can guess at is IDE01928-IDE01932 range. "quantity control valve" is a TDI term for the HPFP regulator.
The IDE01932 is always looked interesting, but never found what it actually means or how to interpret it.

I see no reason to be replacing anything based on just this. You need to determine why the high rail is falling short sometimes and other times not.

[Raiderv13]

Ok. I will log other IDE's. I'll let you know

[leon7891]

Hello Raiderv13,

did you get to know what the issue was ?