Low fuel pressure

[PaulGTI]

Hey guys, im new around here, i've got a 2007 GTI with a BPY engine
My problem started at 88.000km when i had 3 fuel cuts on the highway went to the dealer and after a scan they found the low pressure fuel error
Back then i had only APR stage 1 everything else was stock. The dealer deleted the error and since then no troubles , i changed the fuel pressure sensor on the hpfp. At around 93000km i had check engine on, with the same error but no cuts, after 2-3 logs we saw that the low pressure pump was doing 3.3 pressure instead of 5, changed that and the control unit of the pump and the problem is still there , at full load the pump does no more than 3.3 pressure, and should be doing at least 5...
Now the car has Revo stage 2 with ATP downpipe 3" and EVOMS air intake, don't know if it matters but that's all the things i've changed...
I attached the last log i have. Thanks

 

[petsy]

Have you checked your cam follower recently?

 

[PaulGTI]

at 85.000 km , now ive got 96.000, the cam follower can cause low pressure?

 

[petsy]

Yes and even fuel cuts...

 

[PaulGTI]

Ok thanks i'm going to check the cam follower tomorrow morning

 

[BoardSnow6]

do you know how to access it? If you dont there's a diy on here somewhere...

 

[Tmsracing37]

Did you change the fuel filter at any time?

 

[petsy]

Out of interest my lpfp output pressure is only above 5 bar at around 2k then drops back when logging to around 4.5 bar at red line. Is this normal or should the value stay constantly above 5 bar?

 

[PaulGTI]

well i know where its located , but im gonna take it to a dealer i don't want to make it worse , but i'll check for the diy maybe for the future , thanks

yes i changed the fuel filter at about 92k km when i changed my oil and all the other filters, why?

the guy from revo in my town has also a gti and we logged his pump and its not dropping under 5 at full load, the ecu asks for 4.89 and it gives 5-5.5 or even more. from what i know and heard for most people it drops at red line , and 4.5 i think its ok

LE: found the diy , http://www.golfmkv.com/forums/showthread.php?t=102858&highlight=cam+follower+diy

 

[TheLegend]

Well my GTI was kind of doin the same thing, turns out my low pressure pump was in bits inside the tank.

 

[UG_GTI]

I would not look into the high pressure issue until the low pressure issue is solved. I see that you have taken care of all the basics with the pump, module, and filter. The next thing is making sure you have good power and ground supplied to the fuel pump control module. Low supply voltage or a poor ground is going to limit the pressure that pump can put out. When the low side fuel pressure is low the high side can not be expected to keep up.

 

[PaulGTI]

well guys i did everything yesterday, checked the voltage , checked again with another module , checked everything and still the same problem ... my pump pressure doesn't exceed 4.13 and if i rev it up it goes down under 4...

 

[UG_GTI]

I will check my low side fuel pressure today to compare. Ill let you know.

 

[Fernas]

Thread jacking here, how do i check the LPFP pressure?? im sure with the vag-com, but which block?? Thanks

 

[UG_GTI]

Value block 103 shows low side pressure. 106 for high side. I just checked mine and was pretty steady 4.5bar no matter what.

Looking back at your log I see it never goes really goes over 4 bar. The fuel filter for 2.5L engines is set to bleed pressure at 4 bar. I think you may have the wrong fuel filter installed. Check for a stamp on the filter that either says 4 or 6.5 bar. 6.5 bar is for 2.0t. My hunch is that the first time the fault was set the low side pressure sensor was going bad. You should have a sensor ending in "j". Now that you have the 2.5 filter installed you can not get over 4 bar. The fuel pressure regulator is built into the filter and before the sensor.

Another good test I read today was to checked voltage a pins 1 and 5 at the pump after module. 5v is a good reading at idle, no load. If lower, the module is most likely bad. If higher the pump/filter is not putting out enough pressure.