hhughes1

July 2010: During a 30 minute drive, motor suddenly has no power, won’t rev past 2000 rpm and shudders violently at a stop. CEL begins flashing and I pull over and have it towed to the dealership. Diagnosis is a mystery, cylinders 1-4 are all miss-firing for unknown reasons. Cam sensors are replaced under warranty but no change. Then the cams are “re-taught” proper position relative to the crank and all is fine. I pay for a couple hours labor and the tow because they feel it may be a tune related software issue. They had the car for 3 days so I feel fine with the outcome. Car is fine from that point forward.

Fast forward May 2011: Same issue starts again however after pulling over and shutting the car off the car starts back up and runs fine. Next morning it acts up again but after shutting it down it restarts and I drive it to the dealer”s new location near my home. They have it for the afternoon, the same codes about cylinders 1-4 misfiring are showing. Their brilliant deduction is that the headers are producing to little back pressure(<800) and the tune is causing the problem because of that. I had given them a copy of the previous service report to no avail. Can’t explain why it only affects one bank of cylinders and not the other or how it could just start happening out of the blue. They give me back a car that won’t run and charge me $135 for the expert diagnosis. We will transport the car to the original dealership today where I am sure they will be able to correct the issue fairly quickly but I am concerned about what could be causing the issue. I feel that it must be a mechanical problem with the timing system that is allowing things to get slightly out of synch given that it is the same cylinders affected the same way.

Thoughts??

Hopefully it will be back up and ready for Road Atlanta next weekend.

4ramin

Have them replace the air flow meter

mthis

Have them check your 02 sensors. I had a issue similar and it turned out to be 02's.

GMW

Check and possibly replace the mass air sensors. Replace them if they show even a small fault on the star diagnosis system. (A small fault on the Star Diagnosis system is shown with a small f versus a Capital F for big faults. :-) In this case a small f will cause problems if it keeps re-appearing after being erased and some driving.

There are two air sensors. One located on each 'AMG' cover for the engine air filters. If those have even a small problem you can have uneven acceleration, bad idle or worse depending on how gone they are.

BFNYM156

we have the similar tunes, but I haven't had this issue so far, other than engine limp modes (b/c of engine and transmission overheat), keep us posted

aroonkl

hhughes1,
It happened to mine last month. It had misfire on all right bank, cyl 1 2 3 4.
At first it came as not smooth idling. Till couple days later it shew misfired.
The mech changed o2 sensor, crank case hose and intake manifold. He suspected plastic valves inside my intake manifold not working right. Now the car is good.
(My car has MKB header but no tune yet.)

xtyper

Please keep us posted.

I'm really anxious to find out if it is at all tune related, however since you went with Kleemann, I can't imagine that would be the case.

aroonkl

It happened to mine with no tune.

xtyper

Any updates?

hhughes1

Working on it today, the only thing I know is that it is not a cam/crank sync issue this time. Seeing that it is only affecting one bank of cylinders should make identification easier.

TTMotorsports

SMALL FAULT vs. LARGE FAULT

A lower case "f" means that an incident happened(could be only once) but the corresponding computer took a freeze frame of the episode and it is STORED so you can print out the information of what actually happened. Once you clear the code it is removed and will not come back unless there is another episode like the original one.

An upper case "F" means that there is a problem in the corresponding computer and it is CURRENT and STORED and you CANNOT erase it until the problem is fixed.

TTMotorsports

Did you have any codes stored in the ECU? What did they find when they ran the quick test?

They should have a ton of data that is stored in the ECU from the moment it happened. GL with finding this gremlin.

hhughes1

The misfire issue is specific to cylinders 1,2,4 only. They switched coil packs with 1&3 and the problem remained in 1. Right now they think the tune files may have been corrupted and we may be reflashing back to stock to see if that clears the problem. The car was at a local shop getting a Sparco seat installed for 2 days and the problem started on the way home. Someone may have been curious and tried to access my tune with their programmer?

xtyper

Uh oh...this is certainly not what I wanted to hear given that I am getting my MBH headers and Kleemann header matched tune installed tomorrow. But just to be clear, you don't think the original tune file loaded was corrupt, but rather may have become so when someone else tried to tamper with it?

hhughes1

Car has run great with this setup for nearly 2 years now. Something ?? failed last week but figuring out what has been difficult. The tampering is just a theory but very coincidental.

xtyper

Got it. Hope you get everything resolved soon.

blownS

Had the same issue with my '09. Was serviced on 3 separate occasions over 1 yr period. Dealer said it was faulty/failed fuel injectors, and replaced them on cyls 1-4 under warranty.

I doubt it is ur tune.

hhughes1

3 injectors fail at one time?

blownS

First time I brought it in, they replaced 2. Problem went away, then returned. Brought it back, and they replaced the other 2.

It's been running now since January w/out issue. *knock on wood*

hhughes1

Still no resolution from MB. Sure seems like several members are having misfire issues lately according to various threads.

mthis

There should be a sticky about issues and what dealers do to fix the problem.
That would help everyone gather info and tell the dealer what to try to fix.

ZephyrAMG

++++1 again, Great IDEA....***hint, hint Mods****

SonnyakaPig

In a perfect world the dealer would take the initiative.

4ramin

Any luck yet?

grane

Just had a full plug replacement, engine air filters and fuel filter.

Took long trips from NNE to Ct and then college reunion in PA, back to CT.

Lots of dodgy gas stations, 91 oct gas only, did not add Techron and no Shell stations. back toNH on lousy noname gas. for the first time car did not start on first turn of the key.

On return toCT misfire on #3 cylinder filled up with Shell 93 and Techron and car is smooth.

Think we are getting lousy gas in general, and there is the transition to the summer formula. I shall stick to top brand gas and add Techron to keep everything clean. Just one piece of junk can cause those misfires and one gets electric codes that actually caused by crummy gas.

Unfortunately if you do not make a discipline MAFs and injectors want replacing.