P0087 code, new filter, rail sensors, y94???

[jayy]

hi guys, my 250cdi w212 om651 has an issue under load, p0087/91 code and limp if im pulling onto a motorway, or call for load to overtake. 50k, full history. Replaced following with origional merc parts, fuel filter, both rail sensors, air filter, oil and filter, turno-intercooler boost pipe, full software updates to eliminate any software issues. No boost leaks, dpf regen cycles are fine. Star diagnostic is picking up no faults. If im driving local in "E" mode, sitting at 30mph at low revs and out my foot down just before it hits 2k it feels like its labouring, throws eml and goes into limp. Has anyone on here ever changed the y94 quantity control valve on the hp pump? Can't think of anything else atall. Thanks in advance, jay.

 

[Scottmars]

hi guys, my 250cdi w212 om651 has an issue under load, p0087/91 code and limp if im pulling onto a motorway, or call for load to overtake. 50k, full history. Replaced following with origional merc parts, fuel filter, both rail sensors, air filter, oil and filter, turno-intercooler boost pipe, full software updates to eliminate any software issues. No boost leaks, dpf regen cycles are fine. Star diagnostic is picking up no faults. If im driving local in "E" mode, sitting at 30mph at low revs and out my foot down just before it hits 2k it feels like its labouring, throws eml and goes into limp. Has anyone on here ever changed the y94 quantity control valve on the hp pump? Can't think of anything else atall. Thanks in advance, jay.

Did you ever sort this? I think I have the same issue

 

[W1ghty]

Did you ever sort this? I think I have the same issue

So the car has been on Star ?

 

[Scottmars]

No a snap on something or rather scanner. It says P0252, the output for quantity control valve has a malfunction. For current has not been attained.

I've changed the sensor but maybe it's the wiring or who knows. Going to get it on star and see what is wrong properly I think

 

[mersum1es]

FQV is quite common culprit, though I would get it testes by SDS where individual test for each component exists...

 

[Tuercas viejas]

First to understand how the system works and its potential faults , you first need to know the operating pressures, operational phases, like when its on mix mode and rail pressure control within the operating cycles.
Furthermore often advisable to do an SCN code when doubts exist after throwing a bunch of parts at it .
Has that been done ?
Tuercas Viejas

 

[Scottmars]

Hi thanks for the reply. I changed the FQV myself but it hasn't fixed the problem.

I don't know if it needs telling it has a new one or programming in? My mates scanner has a fuel quantity thing I can run so it can learn the values but I haven't tried it. Wasn't sure if I should or not. I think he has a solus ultra.

I haven't done any of this no. Will his scanner do what is needed or will I need to go to someone with star?

 

[Tuercas viejas]

Snap On Solus is a good tool and you have to make sure its updated with the latest programs.
Even then with MB platforms sometimes it doesn't like gaining access through the platform or model designation drop down menu and do adaptions etc; ,in fact sometimes it just won't even communicate.
But, if you know your engine /powerpack description/designation , look for the same, against a different platform but having the same engine and "back door" access it.
It does work if you can get access ,& we have verified its abilities against X Entry at dealer level, and got a thumbs up .
Ask your mate what program update is loaded on the tool ?
Tuercas Viejas

 

[Scottmars]

Snap On Solus is a good tool and you have to make sure its updated with the latest programs.
Even then with MB platforms sometimes it doesn't like gaining access through the platform or model designation drop down menu and do adaptions etc; ,in fact sometimes it just won't even communicate.
But, if you know your engine /powerpack description/designation , look for the same, against a different platform but having the same engine and "back door" access it.
It does work if you can get access ,& we have verified its abilities against X Entry at dealer level, and got a thumbs up .
Ask your mate what program update is loaded on the tool ?
Tuercas Viejas

Hi there

He says it is updated via the snap on subscription to the latest one and it's actually a modis ultra not solus.

What is the SCN code you speak of? Is that a reprogramming of something? Thanks

 

[Tuercas viejas]

SCN coding is an MB term for adapting items like sensors modules etc to an MB vehicle/platform
Its best described as a cell phone or computer software update to allow full parts communication after replacement.
Tuercas Viejas

 

[mersum1es]

But does FQV really need coding? It also depends on car age when SCN comes more common.

 

[Tuercas viejas]

Yes that's correct.
The coding & adaption for a Sprinter say up to year 2013, is different than for a 2016 unit.
TV

 

[mbe350]

hi guys, my 250cdi w212 om651 has an issue under load, p0087/91 code and limp if im pulling onto a motorway, or call for load to overtake. 50k, full history. Replaced following with origional merc parts, fuel filter, both rail sensors, air filter, oil and filter, turno-intercooler boost pipe, full software updates to eliminate any software issues. No boost leaks, dpf regen cycles are fine. Star diagnostic is picking up no faults. If im driving local in "E" mode, sitting at 30mph at low revs and out my foot down just before it hits 2k it feels like its labouring, throws eml and goes into limp. Has anyone on here ever changed the y94 quantity control valve on the hp pump? Can't think of anything else atall. Thanks in advance, jay.

Did you ever get to the bottom of this and identify what was causing the issue?

 

[W1ghty]

Did you ever get to the bottom of this and identify what was causing the issue?

He hasn’t looked at the forum since January buddy , so who knows

 

[mbe350]

He hasn’t looked at the forum since January buddy , so who knows

Yea, noticed he hasn't been active for a while.

Who knows though, maybe he'll see an e-mail alert and he might have an update - long shot I know, but curious as have a car with the same symptoms.

 

[W1ghty]

Yea, noticed he hasn't been active for a while.

Who knows though, maybe he'll see an e-mail alert and he might have an update - long shot I know, but curious as have a car with the same symptoms.

Let’s hope so

 

[jayy]

SORRY GUYS!!!!! The P0087 low fuel pressure code still pops up under load, along withceml light, engine of and on and it clears, eml clears on 3rd ignition cycle. I have an icarsoft 2 my tool, and it's amazing, I clear the Temporary fault straight away. It happens maybe once or twice a week. Local indy has scanned and said the y94 has a fault, and that they where very common on thr w212 om651 engines, a lot of cars had them replaced within months of ownership however a recall was never carried out. I've been told to leave it be, and 16k miles later its still not a permanent issues. However I'm soon to sell the car and will be getting it replaced for peace of mind for the new owner, I have the original mercedes part here cost £138, Indi quoted £350 to fit, pain in the ass job, egr cooler has to come off along with the intake mani that can be a Ballachulish

 

[kingkhan]

Mine had an issue with y94 quality control valve. Symptoms were...when car was driven for 5minutes from cold, the car started jolting, like fuel starvation, then if i turned it off it wouldn't start properly. It would turn off with zero fuel pressure and stall.

However on a cold start it was fine...as soon as the fuel warms up above 10degrees ot swtiches to u94 hence why it causes problems ahen car has been on for few minutes .

If cold start is a problem, then its the fuel pressure regulator on the fuel rail .

It takes 1hr to get to the y94. You only need to remove egr cooler, EGR pipe, intake elbow only and then you can access the y94. One screw was very tight so i cut a 8mm spanner and used and torx bit in the head.see picture below. I wouldn't pay more than £60 labour to get this replaced. Easy job if you know how to do it .

Heres a small video i made to help as i couldn't find much info on it

To view this content we will need your consent to set third party cookies.
For more detailed information, see our cookies page.

Accept third party cookies