GOLFMK8
GOLFMK7
GOLFMK6
GOLFMKV

P310B Fuel Pressure Outside Specification

GTI's

Go Kart Champion
Location
MD
From VW

TT 20-06-101

2006-2007 Vehicles with 2.0L FSI Engines - Low Fuel Pressure DTCs Aug 24, 2007 - UPDATE


If you have a complaint of DTCs for the low side fuel pressure being out of specification (e.g. P310B), check the fuel pressure with BOTH a mechanical gauge and by the display in Measured Value Block 103. The readings should be 1 bar higher in the MVB due to reading atmospheric pressure + fuel pressure. If the mechanical gauge reading is within specification BUT the MVB 103 reading is not 1 bar higher, check for a possible faulty G410 Low Fuel Pressure sensor.
 

ROH ECHT

K04 PLAY
Location
PDX OR
Car(s)
2007 MKV GTI
Thank you. I believe my shop just hooked up the gauge to it today and checked for bleed back after priming and there was none. I didn't remember what they said the gauge pressure was when it was taken for a drive. I did go out and replace the G410 after the first drive and it didn't get taken out for a second run because I wanted them to figure out a way to hook up a second line to the fuel return line from the filter to the lpfp and then drive it. Once with the return line open and again with its hose clamped shut to see if the filter regulator was returning fuel under load. Even though it isn't showing pressure bleed-back...under load is the only time it shows low fuel pressure. So I want them to confirm the filter regulator condition tomorrow and also report what the low pressure is both on the gauge and in the data. Last thing will be to remove the upgraded lpfp and pop in the new oem.
 
Last edited:

ROH ECHT

K04 PLAY
Location
PDX OR
Car(s)
2007 MKV GTI
OK, I have some results to report. It seems I skipped a step that may or may not affect the performance of a newly installed pump. That step being;
9 – reinstall the assembly into the fuel tank and attach a length of hose to the outlet of the pump assembly allowing it to drain into a fuel safe container and prime the fuel pump assembly.

After pressure testing everything with an incorrect gauge (explain in a moment) and replacing the G410 and the fuel filter, nothing changed as it continued to run poorly. Then after swapping the fuel pressure gauge because the new one was only working as a compression tester would in showing the peak pressure and not the live "up and down" pressure...we found a gauge that wouldn't stick at its peak pressure. My tech went for a drive and it had somehow fixed itself. Leaving me to believe it had a sort of "vapor lock" in the system so to speak, due to me not priming it upon installation. My tech, when he got back, said "I don't know how but it runs like a raped ape now."
 
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