R320 Bluetec- miss above idle, no power, but NO CODES!
 

This car has a miss above idle, and has very little to no power. I scanned the 2009 R320 with my Icarsoft MB II, and found no codes in any of the systems (SCR and engine). It was running fine a couple months ago with a CEL from a bad DEF pump. I replaced the pump, and it has not ran right since. The pump seems to work, as the fault code did not come back (or any other fault code for that matter). The engine is an OM642 just like those in the E class, Sprinter, and others. Any ideas?

Check the turbo actuator linkage there may be some play in it, not enough play to trip it into throwing a CEL but enough to cause a stumble. Plastic worm gear wears on these and causes this issue.

I would suspect inadequate fuel pressure/fuel flow.

Thanks, that is an easy check.

I checked the live data, but I am not sure exactly what I am seeing, or if the values are not what they are supposed to be. Again, this all started right after the DEF pump replacement. I can't imagine how they could be related, but stranger things have happened.

I have had bad injectors not throw a code. The injector failed by not holding pressure and leaking through the fuel return circuit.

How many miles are on it?

150,000

Any knowledge if the swirl flaps are functional?

Unfortunately you may have to put a Xentry on it.

There are some things that the iCarSoft will not find that a Xentry will. Seen it first hand having both units.

Some faults show up as 'events' in Xentry instead and these do not appear on the iCarSoft. Events do not set a CEL or an OBDII code so you can't find them without Xentry.

I think it would surely throw a code for that.

I fear you may be right. That also might be the only way to find out if it has a marginal injector as GregMN points out. Thanks all, Rich

An Autel diagnostic system would tell you issue too.

I have had a lot of experience with an engine problem and there were no codes. Local shop has the latest and best analytical equipment but no codes, dealer also found no codes, dealer appealed to the factory for help but found no solution. Entire problem from beginning to end took about a year and cost me over $5,000. Could have been much higher except dealer did a lot of experimenting for free. I posted the entire story on this site. The only things in common with your problem are same engine and no codes. I finally installed a new cheapie starter because I thought maybe it was cranking a little slow and to replace the starter I had to remove a portion of the exhaust system including that "large tank". There were three wires leading to the exhaust system that I had to unplug and then reconnect after the starter was replaced and the exhaust system re-assempled. The car now performs perfectly. I suspect one of those three wires that I unplugged and then connected again was the culprit. No codes.

https://www.youtube.com/watch?v=xjSWLq7OvHE

I set up the test in the video with longer tubes ( about 8" ) and ran the engine until one of the tubes was over half full. The tubes that filled up more than the others were the bad injectors.

https://www.youtube.com/results?search_query=diesel+injector+leak+off+test