P0087 & P2047 OBD II Codes after CEL and loss of power on 07 E320 Bluetec

[bigchingan]

Just 3 days ago, my car threw a CEL while driving. Power seemed reduced, but I was in low speed traffic and just wanted to get home so I didn't test it. Started it up and drove it a few times, and it drove fine and the CEL light went away. Today I was driving about 50MPH when the light came on again. This time, because I was merging onto a highway, I felt an immediate impact on performance. The car almost didn't want to Rev higher than 2K, even with flooring it. I could manually downshift and get it above 2K, but didn't want to force it. I could still accelerate to 65, although very slowly (almost like it was now naturally aspirated, but with even less power compared to a 96E300D which I have and is NA).

Scanned it with Torque and a bluetooth OBDII scanner, and it came up with the following codes:

http://www.obd-codes.com/p0087
http://www.obd-codes.com/p2047

Some quick googling looks like it could be related to a fuel pump issue, but I haven't heard of too many of those with these engines.. Looking for some guidance.

[bigchingan]

Originally Posted by bigchingan

Just 3 days ago, my car threw a CEL while driving. Power seemed reduced, but I was in low speed traffic and just wanted to get home so I didn't test it. Started it up and drove it a few times, and it drove fine and the CEL light went away. Today I was driving about 50MPH when the light came on again. This time, because I was merging onto a highway, I felt an immediate impact on performance. The car almost didn't want to Rev higher than 2K, even with flooring it. I could manually downshift and get it above 2K, but didn't want to force it. I could still accelerate to 65, although very slowly (almost like it was now naturally aspirated, but with even less power compared to a 96E300D which I have and is NA).

Scanned it with Torque and a bluetooth OBDII scanner, and it came up with the following codes:

P0087 Fuel Rail/System Pressure Too Low
http://www.obd-codes.com/p2047

Some quick googling looks like it could be related to a fuel pump issue, but I haven't heard of too many of those with these engines.. Looking for some guidance.

Follow-up to this: The issue was related to a small crack in the ductwork feeding air to the turbo. Once the car warmed up and I accelerated hard, the boost was enough to force the crack open and let pressure escape. Replaced the ductwork and everything was fine.

[GregMN]

This might be a lesson to others who read their codes and then google them.

You need to find the make and model and engine specific reason for the error codes. Then you need to understand that an error code for one system may have nothing to do with that system, but might be caused by something in a different system.

When I got my ML with the 642, I thought great, this engine management system is so smart that it will tell me exactly what is wrong with it so that repairing it will actually be easier than an earlier engine. As you can see by this example I was mistaken. Sometimes it is easier and sometimes it seems to be telling jokes or making sarcastic remarks.

[jay_bob]

The intake air plenum on an OM642 is a joke.

Made worse by the design, and ham fisted mechanics trying to change air filters improperly.

The original part is like $500 because of the dual MAF sensors.

[GregMN]

Originally Posted by jay_bob

The intake air plenum on an OM642 is a joke.

Ya. A joke is suppose to be funny, but that one is only funny if it's on someone else's car, not mine.