D5 (D5244T to 2005) High and low fuel pressure errors

[Lancee]

"and vide shows the current through the sensor to drop as the fault occurs".

Cleaning fuse blades costs nothing!

[Shadeyman]

At one end of the fuel rail is the "fuel pressure sensor", at the other end of the rail is the "fuel pressure relief valve", this helps maintain the correct fuel pressure. Has it been checked, it may need replacing?

EDIT.
Fuel pressure is regulated by an electric valve on the high pressure pump, may be it, its connections and wiring should be checked to?

[reggit]

Thanks shadey - I wasn't sure what the connector on the high pressure pump was, but I've checked the wiring (all OK) and tried a complete HP pump substitute with no difference.

The wiring to the fuel rail sensor and fuses also check out OK.

Clutching at straws now and have decided to replace the fuel filter (again) with a 'Volvo' branded one.

I've noticed that the car is running much better, although not perfect now the fuel level has fallen below 1/2 tank - this is the issue I'm struggling to get my head round as it appears to be related to the quantity of fuel in the tank and gets better to perfect with a low quantity of fuel.

[JonnyA]

Hi

interesting reading this post as I hate problems that won't reveal their cause...firstly I should say I know nothing about the fuel system set up... but thinking about your description of the problems makes me wonder if there is a problem with the breather system in to the fuel tank leading to a sealed system that restricts the fuel flow from the tank.
As you say this is worst when the tank is full and improves as the tank is emptying ... when the tank is empty there is more volume of air so less vacuum develops than when it is full.
If it happens under engine load - fuel demand up so more suck on tank.

I may be barking up the completely wrong tree...

[reggit]

Originally Posted by JonnyA

I may be barking up the completely wrong tree...

I've been doing a lot of it!

Good thinking on a vapour lock - I've never thought of this, I'll check next time the car plays up.

I've just changed the fuel filter for a genuine 'Volvo' one, although the car was playing up last time I changed it, so not convinced it will do anything - unless there have been 2 issues....

We're off on our holiday in Snowdonia in a few hours, should be interesting driving up the hills!

[reggit]

Well Bernard, it looks like you where right. I suspect I've had an intermittent fuel pump. It's got a lot worse today, and to cap it all the car stopped on the A55 with 1/8th tank remaining. Cue lots of bouncing the car to slosh enough fuel to the pick up to make it to the nearest garage. Fortunately it was only 3 miles away!

We on holiday in snowdonia at the minute, so learning how to drive up hill without inducing limp mode. Holding a low gear seems to work, I assume by spinning the HP pump faster.

I don't know what was causing the high pressure fault, suspect the fuel rail sensor was also faulty as that one hasn't returned since I changed it.

No more 'it's a nearly new replacement' pump this time. Think I'll stump up for a brand new one!

[reggit]

This is still confusing me as the blooming thing seems to be working intermittently. I don't want to spend £300 to find out there is still an issue.

I'm going to follow Bernards advice and wire a volt/amp gauge to the pump, so I can see what it's doing.

Found a suitable dual display which I should be able to temporarily mount on the dash without doing damage so I can monitor it whilst driving.

[forumoto]

Following this thread

[reggit]

Just thought I'd update this, in case someone stumbles across it in the future.

I never got round to wiring the volt/amp gauge to the pump, as I became convinced it was the issue as the issues returned, limp mode started appearing for fun and usually at the most inopportune times.

I've now fitted a brand new tank pump £245 (ouch!) and all issues have cleared.

[drugiboksar]

I had errors 2501 pressure too high, 2503 pressure too low, 2502 pressure too high on OBDII P0094, P0087, P0092. I made the leackback test , all injectors produced less than 40 ccm /min, but one injector more than the others. I swaped the injectors with known working old injectors. The errors persisted. Than changed the pressure regulator on the HP Bosch pump, errors gone.