Mercedes E 220 CDI P0252 & P0087 Low fuel pressure problems
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Mercedes E 220 CDI P0252 & P0087 Low fuel pressure problems
Hi,
I’m having trouble with my E-Class. The car is a Mercedes E 220 CDI from 2012 with 340,000 km on the meter.
Six weeks ago, I was driving on the highway when the engine light lit up and the car went into limp mode. I read the code with my cheap reader, and it said “P0252 Injection pump fuel metering control A range/performance (cam/rotor/injector).”
I erased the code since I had been driving a little harder than usual, and it worked.
Two weeks later, the engine light came back again (with limp mode) while driving. Now with the codes “P0252” and “P0087 Fuel rail/system pressure - Too low bank 1.” This time, I changed the Y94 sensor (quantity control valve) on the high-pressure pump. The metal around the sensor was torn apart, but it looked like all the parts were still there and hadn’t been pumped away in the fuel system. I cleared the codes, and the car ran great.
Another week after that, the check engine light came back again while accelerating onto the highway. This time with only “P0087.” I spoke to a mechanic who said that it’s probably the Y74 sensor (pressure regulating valve) on the rail that’s broken so i changed the sensor. While I was at it, I cleaned the B4/6 rail pressure sensor as well. I cleared the code, but it didn’t help.
The car runs great, with no misfire or strange sounds. The code only comes when I accelerate steadily with no downshift, for example, entering the highway. Driving fast on a curvy country road with lots of braking and acceleration works great as well.
I did a simple DIY injector leak test at idle. One injector had no return at all, two gave about 15 ml, and the last one gave about 30 ml in 3-5 minutes. Is that good enough?
The fuel filter (Mann Filter) was changed 6 months ago.
I have an appointment booked in three days with a mechanic with a Star unit. Hopefully, they can find what’s wrong.
Do you guys have any idea what could be the problem?
I’m having trouble with my E-Class. The car is a Mercedes E 220 CDI from 2012 with 340,000 km on the meter.
Six weeks ago, I was driving on the highway when the engine light lit up and the car went into limp mode. I read the code with my cheap reader, and it said “P0252 Injection pump fuel metering control A range/performance (cam/rotor/injector).”
I erased the code since I had been driving a little harder than usual, and it worked.
Two weeks later, the engine light came back again (with limp mode) while driving. Now with the codes “P0252” and “P0087 Fuel rail/system pressure - Too low bank 1.” This time, I changed the Y94 sensor (quantity control valve) on the high-pressure pump. The metal around the sensor was torn apart, but it looked like all the parts were still there and hadn’t been pumped away in the fuel system. I cleared the codes, and the car ran great.
Another week after that, the check engine light came back again while accelerating onto the highway. This time with only “P0087.” I spoke to a mechanic who said that it’s probably the Y74 sensor (pressure regulating valve) on the rail that’s broken so i changed the sensor. While I was at it, I cleaned the B4/6 rail pressure sensor as well. I cleared the code, but it didn’t help.
The car runs great, with no misfire or strange sounds. The code only comes when I accelerate steadily with no downshift, for example, entering the highway. Driving fast on a curvy country road with lots of braking and acceleration works great as well.
I did a simple DIY injector leak test at idle. One injector had no return at all, two gave about 15 ml, and the last one gave about 30 ml in 3-5 minutes. Is that good enough?
The fuel filter (Mann Filter) was changed 6 months ago.
I have an appointment booked in three days with a mechanic with a Star unit. Hopefully, they can find what’s wrong.
Do you guys have any idea what could be the problem?
MBWorld Fanatic!
Joined: Dec 2011
Posts: 1,694
Likes: 489
From: Spain UTC/GMT +2 hours
W213 All-terrain
The Y74 can't be exchanged, as the rail need to be calibrated over valve (tiny holes over tiny holes ) and this is impossible to do without proper diesel workshop equipment. MB only sell rail together with the valve.
As I wrote here several times, Pxxx means nothing for MB. It's just a generic code.
P008700 The fuel pressure in the system is too low.
P008709 The fuel pressure in the system is too high.
P008791 The fuel pressure in the system is too high.
P008796 The fuel pressure in the system is too high.
As I wrote here several times, Pxxx means nothing for MB. It's just a generic code.
P008700 The fuel pressure in the system is too low.
P008709 The fuel pressure in the system is too high.
P008791 The fuel pressure in the system is too high.
P008796 The fuel pressure in the system is too high.
Last edited by trigital; Nov 18, 2024 at 11:29 AM.
Out Of Control!!
Joined: Apr 2019
Posts: 11,957
Likes: 6,796
From: Silicon Valley
W212 MY'14 M276-3.5NA @75kMi
tank supply...
I bet your pressure delivery issue has to do with low pressure side... related to the filter service that was done earlier.
Stop changing parts... compare vehicle LO/HI pressures to WIS specifications. This will narrow down scope of parts to be considered.
Stop changing parts... compare vehicle LO/HI pressures to WIS specifications. This will narrow down scope of parts to be considered.
Last edited by CaliBenzDriver; Nov 18, 2024 at 12:34 PM.
MBWorld Fanatic!
Joined: Dec 2011
Posts: 1,694
Likes: 489
From: Spain UTC/GMT +2 hours
W213 All-terrain
W212 has FSCU and low pressure sensor, also rail has high pressure sensor, so everything is already compared, that's why the fault code is alive.
Out Of Control!!
Joined: Apr 2019
Posts: 11,957
Likes: 6,796
From: Silicon Valley
W212 MY'14 M276-3.5NA @75kMi
Here I think fuel pressures are the first thing to read.
Seems we are dealing with lean starvation... tank supply!
MBWorld Fanatic!
Joined: Dec 2011
Posts: 1,694
Likes: 489
From: Spain UTC/GMT +2 hours
W213 All-terrain
Y74 can't be unscrewed as will never be screwed correctly. That's the problem here, in my opinion. Another new rail with untouched y74 at least will provide a reference for ending the diagnosis.
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Hi,
I’m having trouble with my E-Class. The car is a Mercedes E 220 CDI from 2012 with 340,000 km on the meter.
Six weeks ago, I was driving on the highway when the engine light lit up and the car went into limp mode. I read the code with my cheap reader, and it said “P0252 Injection pump fuel metering control A range/performance (cam/rotor/injector).”
I erased the code since I had been driving a little harder than usual, and it worked.
Two weeks later, the engine light came back again (with limp mode) while driving. Now with the codes “P0252” and “P0087 Fuel rail/system pressure - Too low bank 1.” This time, I changed the Y94 sensor (quantity control valve) on the high-pressure pump. The metal around the sensor was torn apart, but it looked like all the parts were still there and hadn’t been pumped away in the fuel system. I cleared the codes, and the car ran great.
Another week after that, the check engine light came back again while accelerating onto the highway. This time with only “P0087.” I spoke to a mechanic who said that it’s probably the Y74 sensor (pressure regulating valve) on the rail that’s broken so i changed the sensor. While I was at it, I cleaned the B4/6 rail pressure sensor as well. I cleared the code, but it didn’t help.
The car runs great, with no misfire or strange sounds. The code only comes when I accelerate steadily with no downshift, for example, entering the highway. Driving fast on a curvy country road with lots of braking and acceleration works great as well.
I did a simple DIY injector leak test at idle. One injector had no return at all, two gave about 15 ml, and the last one gave about 30 ml in 3-5 minutes. Is that good enough?
The fuel filter (Mann Filter) was changed 6 months ago.
I have an appointment booked in three days with a mechanic with a Star unit. Hopefully, they can find what’s wrong.
Do you guys have any idea what could be the problem?
I’m having trouble with my E-Class. The car is a Mercedes E 220 CDI from 2012 with 340,000 km on the meter.
Six weeks ago, I was driving on the highway when the engine light lit up and the car went into limp mode. I read the code with my cheap reader, and it said “P0252 Injection pump fuel metering control A range/performance (cam/rotor/injector).”
I erased the code since I had been driving a little harder than usual, and it worked.
Two weeks later, the engine light came back again (with limp mode) while driving. Now with the codes “P0252” and “P0087 Fuel rail/system pressure - Too low bank 1.” This time, I changed the Y94 sensor (quantity control valve) on the high-pressure pump. The metal around the sensor was torn apart, but it looked like all the parts were still there and hadn’t been pumped away in the fuel system. I cleared the codes, and the car ran great.
Another week after that, the check engine light came back again while accelerating onto the highway. This time with only “P0087.” I spoke to a mechanic who said that it’s probably the Y74 sensor (pressure regulating valve) on the rail that’s broken so i changed the sensor. While I was at it, I cleaned the B4/6 rail pressure sensor as well. I cleared the code, but it didn’t help.
The car runs great, with no misfire or strange sounds. The code only comes when I accelerate steadily with no downshift, for example, entering the highway. Driving fast on a curvy country road with lots of braking and acceleration works great as well.
I did a simple DIY injector leak test at idle. One injector had no return at all, two gave about 15 ml, and the last one gave about 30 ml in 3-5 minutes. Is that good enough?
The fuel filter (Mann Filter) was changed 6 months ago.
I have an appointment booked in three days with a mechanic with a Star unit. Hopefully, they can find what’s wrong.
Do you guys have any idea what could be the problem?
