whitebandit2.0

2010 E350 Coupe, 117k Miles

I’ve just completed an intake manifold conversion/swap to the M014 composite manifold, including a flash tune from OETuning. Also did the CCV kit from FCP Euro at the same time (oil separator, centrifuge, drip pan, hoses, plugs).

During reassembly it seems I failed to properly reconnect the plugs on the engine wiring harness that’s clipped on the ECU mount (circled in the attached picture).

It was dark, I was holding a flashlight, and I pressed the plugs together but didn’t push them far enough for them to click. Called it a night and forgot to recheck my work when I came back to it the next day.

On initial startup the idle was extremely rough, lots of misfires and flashing CEL.

Pulled the codes from OBDLink and got the following:

P0300 - Random/Multiple Cylinder Misfire Detected
P0304 - Cylinder 4 Misfire Detected
P0305 - Cylinder 5 Misfire Detected
P0306 - Cylinder 6 Misfire Detected
P0273 - Cylinder Injector 5 Circuit Low
P0348 - Camshaft Position Sensor “A” Circuit High
P0393 - Camshaft Position Sensor “B” Circuit High
P2092 - “A” Camshaft Position Actuator Control Circuit Low
P2094 - “B” Camshaft Position Actuator Control Circuit Low

So…errors from pretty much everything on the 4/5/6 Cylinder bank led me to believe I’d missed a plug. Pulled the air box and started checking and that’s when I discovered the loose connection previously described. Reconnected that plug, also disconnected the ground wire, cleaned the contact surfaces, and reconnected for good measure. Checked all the plugs on the injectors, camshaft adjuster magnets, and camshaft position sensors - all were solid.

Started the car up again, no more misfires and flashing CEL, engine seems to be running fairly smoothly however the CEL was continuously illuminated and there was quite a bit of lifter noise from that side of the engine now (Bit of backstory, I replaced all four camshaft adjuster magnets about a month ago and went to 0w-40 oil which completely eliminated the lifter noise).

Thinking maybe clearing the codes would help, I tried to do so through the OBDLink app and it was unsuccessful (maybe because it’s really more for BMW’s), so I tried disconnecting the negative battery terminal for a few minutes to clear them that way. No luck, when I started the car back up the CEL was still on with same codes, and the lifter noise persisted.

At this point I’m wondering if that plug being half connected has damaged the injector, adjuster magnets, and position sensors in question and they need to be replaced? Or could something else be going on?

My plan at this point is to start pulling the engine harness on that side of the engine and basically redo the assembly to see if I missed something else I’m not catching in visual inspection.

Any suggestions or ideas are welcome!

JettaRed

iTrader: (1)

First, get a proper Mercedes scan tool, like the LAUNCH Creader Elite 2.0 BENZ on Amazon, have it tomorrow or the day after, do a proper scan, and clear the codes. Generic OBD are pretty much worthless, and even worse, on Mercedes cars.

It is doubtful you did any damage with the loose connection. However, the codes will persist until you clear them or the necessary number of cycles have passed since you fixed the problem.

By the way, how can you be a member here for 15 years and this is your first post?

SoCalGLK350

Hi,

My situation is extremely similar. I believe I missed a ground/connection during manifold swap which, in effect, ran only bank 1 (cyl 1,2,3) for 2x20 second intervals on a 2011 GLK350 M272 before I corrected. Since then, car is very sluggish and shifting clonks very hard in certain situations, mainly foot off accelerator. Chased a lot of rabbit holes. Turns found I have almost no manifold (absolute) pressure.

I finally have looked into the timing and seen that it looks like one of the camshafts positions is off. I think I jumped a tooth on the timing.

You should look at the timing through the 2 sensor on each bank (see procedure somewhere). Super easy enough to take a look if those 4 stamps are centered at 305* crankshaft.

MBENZTECH

@whitebandit2.0 Check all your grounds. That connector will not damage anything. But if you did leave the ground on the cylinder head covers loose, you just fried that ECU. I have replaced many of these ECU's for other shops around my area because they left the grounds loose, after replacement of intake manifold.