CDI massive loss of power - PeachParts Mercedes-Benz Forum

spark3542 · #1 08-15-2016, 02:26 PM

Twice now in the last week after running perhaps 100 miles, car will go into pseudo-limp mode. By that I mean all gears are available, but fuel to engine is limited, there is certainly no turbo whatsoever, and it upshifts almost immediately yielding extremely slow accelerations. It will eventually reach highway speeds, but asking for acceleration on highway just puts black smoke out the tailpipe.

Rewind a few years,.... I had this same problem, consensus at the time pointed to EGR valve. I opened valve up, it was well crudded. cleaned it, exercised it, put it back together. It ran fine until last week.

Last week, after it went into limp mode, I pulled EGR apart expecting same issue, but it was fairly clean and moved freely and easily. Cleaned it anyway, put it back in.

Limp mode again today. Pulled over, shut off engine, restarted and it ran fine.

No engine codes are set. No CEL on the dash, and my Scangauge reports no codes set.

Has anyone seen this limp mode issue?

monky · #2 08-16-2016, 05:08 AM

Without a code there are just too many things that could cause it to take a guess.

I have a Sprinter that goes into limp mode every 2 weeks, and only the certified Mercedes repair shop is able to delete the code. Sometimes the code will clear by just shutting off the engine and locking the doors, but it will always come back.

I don't remember the code exactly, but it says "offset drift under engine load", something to do with air pressure.

The EGR has been replaced twice, turbo replaced, DPF replaced, turbo checked for leaks, O2 sensors replaced.. the shop believes it's a sensor that is not functioning correctly. Had this problem since I bought the car 3 years ago, luckily the shop deletes the code for free since they don't know how to fix it. To delete the code they have to reset the MAF-sensor or something.

This is why I absolutely despise modern cars..

benzfan109 · #3 08-16-2016, 09:33 AM

I had a problem with my '05 E320 CDI in that it would loose power as in no turbo boost. If you shut down & restarted the engine, it would be OK for a short time. After three drive cycles, the CEL would come on. It turned out to be the electric boost actuator on the turbo failing when it got hot. Ma Benz wants to sell the entire turbo assembly. At 83K I did not think I needed a turbo, so I removed & sent the actuator off for a rebuild. It was the best money I spent. Works great now. But without a code, you really do not know what is going on.

steve tampa · #4 08-16-2016, 09:46 AM

spark3542-I had this problem with my new 2005 with about 17,000 mi. I now have 265,000. They replaced the EGR valve (after trying 2-3 things) I finally got it to a dealer with it in the limp home mode and did NOT turn it off because it would reset and run fine if I did. They changed the egr valve and it's been fine since. I now check and clean the valve on occasion but it's generally clean and it runs like a champ. Don't know what codes it had. I'm traveling now and my paperwork for the fix is at home. steve tampa

spark3542 · #5 08-16-2016, 04:24 PM

Thanks for the replies.

Benzfan...did you also get the immediate upshifting when your turbo actuator went out?

My turbo wheel grenaded itself about 40,000 miles ago, and I replaced just the turbo and transferred the actuator from the old one.

It still seems to me like its EGR, but with it fairly clean and moving easily, it's difficult to troubleshoot.

Perhaps this is forcing my hand to invest in horsepower mods that include EGR delete (for off-road purposes only...

chronometers · #6 08-16-2016, 11:30 PM

Sounds like EGR but it is weird it is not clogged up. Mine acted up like that last year and I cleaned the valve and so far I have not had any more power loss episodes.

Please post when you resolve problem so we know if the problem comes up again on our CDIs.

steve tampa · #7 08-18-2016, 02:32 PM

Spark3542-why not get the part number off of the EGR valve and see if the new dealer part number is different? If so replace with the new one as in numerous posts on another forum, the original one was superseded by a replacement that solved the limp home mode. If it is the EGR. Mine was, yours might not be. If I were home, I could give you the part number from the repair order but I'm traveling. steve tampa

spark3542 · #8 08-18-2016, 06:19 PM

Ok, I did a 200 mile trip today. About 40 miles in, limp mode. Pulled over, cycled key off and on again...reset. About 15 miles later...limp mode.

Lather, rinse, repeat.

After the third time, CEL came on. The code reads P2237, which is O2 sensor, bank one, sensor one.

Ironically, the car ran better with CEL lit...no smoke, no early upshifting, and I had turbo. So I didn't reset the code for the rest of the trip.

Tonight I will swap EGRs with my other CDI, and see if the issue follows the car or the EGR valve. I have another 150 mile trip tomorrow night.

spark3542 · #9 08-23-2016, 01:30 PM

I can't find any reference to what code P2237 could mean on a diesel, since "O2 sensor one bank one" surely references a gasser.

Anyway, swapped EGRs with my other CDI and reset the CEL code. Car ran fine at highway speeds for 140 miles until I took an exit and it went to limp mode. This reflects a drastic improvement from how it behaved with the original EGR. Shut the car off, restarted, no limp mode. It hasn't gone to limp mode since (~200 miles of city driving).

Here's where you'll think I'm crazy...When I swapped EGRs, I stopped getting "water in fuel...visit workshop" message. I had gotten that message every single time I started the vehicle for at least the last 8-10 months. That message has NOT appeared in the 20 or so starts since changing EGRs.

At the risk of stating the obvious, I do not have water in my fuel. I have changed fuel filter several times since getting that message for the first time, drained fuel tank, and have no driveability issues (aside from the recent limp mode).

How EGR and "water in fuel" message are related just stumps me.

spark3542 · #10 08-29-2016, 09:04 AM

EGRs are still swapped.

Original CDI has had 3 limp modes since the swap, over the course of about 1000 miles. This is still significantly reduced from prior to the swap. Still no "water in fuel" messages at all. The limp modes tell me there is still something non-EGR related causing it.

The other CDI has had no limp modes. Probably only about 200 miles on it since the swap.

spark3542 · #11 09-05-2016, 11:23 AM

I found the swirl flap actuator linkage disconnected at the actuator motor end. A tip courtesy of fellow member Catalind.

tyl604 · #12 09-05-2016, 11:28 AM

Let us know if that absolutely resolved the problem. Hope so.

spark3542 · #13 09-16-2016, 02:44 PM

1100 miles now since reconnecting swirl flap actuator linkage. No CEL, no limpmode, and gobs of power again.

spark3542 · #14 09-28-2016, 09:06 AM

Update...
The actuator linkage popped off again. This is a ball-and-socket connection at the swirl flap motor, and clearly the socket has gotten tired over 275k.

This is a 4 inch long linkage, with ball-and-socket at each end. I called MB dealer to get a replacement linkage. They confirmed that that linkage is part of intake manifold assembly, and only sold that way. I challenged them that this is a linkage that is easily removed by hand, but they confirmed that there is no part number for just the linkage. Intake manifold is about $1k, and there's no way I'm replacing that due to a tired 4" long linkage.

I took Catalind's advice to drill carefully through the tired ball-and-socket on the motor end, and feed a wire through, to act as a keeper for the connection.

...easier said than done. There is not access to drill the motor arm with the motor installed, so motor removal is necessary. Removing that motor is only 3 torx bolts and electrical connector, but extremely painful to access. I can only reach near it with left hand, and it ended up being me topside reaching around the manifold, and my wife's small hands on the creeper underneath to get a wrench on those bolts. I seldom have to summon the wife to the garage to help.

funola · #15 09-28-2016, 09:15 AM

How about this?

Envision cutting up a bicycle inner tube to the shape of an Octopus. Tie the tentacles around the ball socket.