W212 250cdi fuel rail sensors

[jayy]

hi, has anyone ever had to replace either of the 2 sensors on the fuel rail on there om651? I'm getting a p0087 and noone seems to be able to pinpoint the issue, 2 merc specialists with star diagnostic still have no clue. Fault comes when under load, on an incline for instance and I push accelerator but hold the gear. Its coming up as an historic failt on the diagnositics. Injectors seem fine, no starting issues, new merc fuel filter. Couple of mechanics have mentioned DRV or pressure sensor on the rain, can anyone on here offer any advice? Thanks

 

[mersum1es]

What is p0087? (we unfortunately cannot remember out of memory all possible codes, and besides if code is pulled by SDS it do have very accurate description given)

One rail end component is pressure regulator valve, another is pressure sensor. They are not sold separately nowadays (AFAIK), but you could use 2nd hand part or try directly Bosch code.

Did your specialists run all tests for fuel systems, hp pump, fuel quantity valve, presure regulator? Did they check injector correlation values and did they do injector leak back test?

If fault code is fuel pressure, most common problems are fuel quantity valve or injector tank line leak. Like said can be tested.

 

[jayy]

Hi, thanks for the response mate. The p0087 is a low fuel pressure fault. Im not sure as to the extent of the diagnostic carried out. They only tested the vehicle at idle and revs, not whilst driving and under load. I dropped the car of at a technician today whos going to use scopes and do some live data logs whilst driving, hes part of the dpf doctor network and seems very confident of theres a fault her will get to the bottom of it. I was thinking it may be software related, I had a remap at a local company 4 weeks ago, however within 12 hours I had them put the original file back on the car as I wasn't happy with how the car was driving, turned out it had a split boost pipe and dpf was filling fast. So had the map removed, fitted a new boost pipe, dpf cycles are fine, however I've been getting this p0087 code since the day they maped the car.

 

[mersum1es]

Remapping sometimes can pop up problems in fuel delivery, but it should not be permanent if normal software is returned. Most fuel component test are done stationary. Tests are automatic or semiautomatic, and they should give a hint if component is failed. Leak test is/can be done without diagnostics.

 

[jayy]

OK mate thanks, my concern was that when the company reinstalled the original file something may of corrupted. Its currently in with the technician so hoping to have an update soon, I believe the hp fuel pumps dpnt often fail on the om651 and the low pressure pump in the tank is giving 3bar on idle so that seems fine, hoping is a sensor on the rail to be honest. Im meant to be driving t Europe in 10 days and dont fancy a 3000 mile journey with fuel low pressure issues.

 

[Ovlov440]

Did you ever get to the bottom of this?

I have the same issue (car occasionally goes into limp mode with code P0087 when under acceleration on an incline). STAR showed an issue with the Quantity Control Valve on the HP fuel pump. This has been replaced but still getting the code (just not as often).