MakUsa

Hi everyone,
I have missfire on cylinder #1 on this 2013 E 350 4 Matic on idle and interior dome light flickering on idle,also the check engine light blinks after 5-10 seconds from first start,if I reset the codes and start the engine and keep the idle above 2000 rpm the check engine does not come back on and the engine seems to run good but as soon as I let it idle it starts to shake and miss and engine light comes back on blinking!!
What I already done so far:
1.Compression #1 cylinder 180 psi
2.Replace #1 injector (Bosch)
3.Replace #1 coil (Bosch)
4.Replace #1 spark plug and index(Bosch)
5.Smoke test intake no external leak
6.Replace ECU
7.Pin wires from ECU to coil
8.Swap injectors and coils
9.Send cylinder head to mashine shop for inspection of the valve seats and springs also pressure test.
Reset all the mixture adaptations after every try and no change still missfire on idle on # 1 cylinder only code every time!!
And one more thing I did remove the fuel rail on bank one and blow air thru and inspect for clogs and no change!!
I need help with this one!!
Thanks.

S-Prihadi

Wow.... this is VERY interesting.

01. What scanner do you have access to at all time ?

02. Do you have a scope ? Prefer 4 channel version and automotive one like from Pico.
With COP ignition waveform sensor.

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Ask : define Misfire is always on cylinder 1. I mean scanner based reading on misfire count and Smooth Running ( Xentry ) ?
or you seen its secondary ignition COP waveform on a scope showing poor combustion waveform ?

JettaRed

iTrader: (1)

Your engine stumbles and throws a DTC when idling. You also get dome light flicker.

1. How many miles on the engine?
2. You are well above the 145 psi lower limit for wear.
3. Did you check compression on the other cylinders? What was it. Delta between 1 and the others needs to be less than 1.5 bar (21.76 psi).
4. Have you tried replacing the A/F (O2) sensors?
5. How old is the battery?
6. Have you checked the alternator?
7. How did you replace the ECU? Who restored the factory settings, etc.?

Jeedie

Interior dome light flickering, that would suggest some serious voltage issues. Cylinder #1 has the longest lead from the ECU and would be the first to be hampered by low voltages, either COP or injector.

I'd start by checking the mains voltage on idle, and test the car with a jump starter or second battery connected.

JettaRed

iTrader: (1)

My daughter has an old Toyota Tundra that she hardly drives. Once, she left the interior lights on which drained the battery to dead. I jump started the truck, but it would die when idling. At first, I thought the low fuel level was the problem, but filling up did nothing to fix the stalling. I would have to keep the RPMs up, which was fun when trying to stop. Finally got the truck home and because it had a mechanical throttle, I adjusted the throttle cable to keep the RPMs higher than normal. Checking with a trusted mechanic, he said that when the battery completely drains, the Toyota ECU gets finicky. He said it should adapt after driving it around a bit. The truck runs, but I never returned the throttle cable to it's previous state.

The point to that story is that your problem could be either one or both of your batteries and/or your alternator. I've been told that bad batteries will eventually ruin an alternator.

MakUsa

i have Xentry scanner also iscan and autologic.
Misfire is on number 1 cylinder it doesn’t change to other cylinder’s by me swapping the coils/injectors.
I do not have scope but I will get one.

MakUsa

1. 145000 miles
2. 180 psi MAC tools compression tool
3.Check #2 cylinder compression 175 psi
4.Can the 02 sensor cause misfire on one cylinder?
5.Battery 1 year old (Bosch) All the tests that I’ve done I use voltage maintainer charger snap on.
Again can I bad or weak battery cause misfire on one cylinder?
6.Alternator checked
7. I bought used ecu on eBay with same part number and used benzmonster to reset it and I program the driver authorization to my car with xentry the car starts and drive with same issue #1 misfire.

MakUsa

All test and diagnostic I performed on it I have snap on charger on flash program set on the car.

MakUsa

Also the idle drops too low that’s when the dome light start to flicker.

MakUsa

I get what you’re saying but :
1.Why number 1 cylinder ?
2.At all the times I have battery charger on flush/program connected and charging.

JettaRed

iTrader: (1)

I know it's a pain, but I would check all of the cylinders for compression. The firing order for the Mercedes M276 V6 engine is 1-6-3-4-2-5. So I would be particularly interested in cylinders 5 and 6 since they fire right before and right after cylinder 1.

With regards to weak batteries, a failing alternator, or marginal O2 sensors, they may affect misfires in a single cylinder. As mentioned either here by @Jeedie cylinder 1 is the furthest from the ECU. The flickering dome light shouldn't be ignored. These cars are so sensitive to available voltage, you can't rule out a marginal battery or other electrical component. I had intermittent failures of my Distronic, Blind Spot Assist, and Pre-Safe Braking until I replaced both batteries in my SL. The batteries and alternator tested fine, but since I replaced the batteries I've not had that happen again.

MakUsa

I will listen to your advice and check compression on all 6 cylinders.
Also I will run one more test on the alternator and battery.

MakUsa

What I think is happening so far I might be wrong the ECU is picking up that something wrong is going on with cylinder #1 and shots down injector #1
The reason????

JettaRed

iTrader: (1)

I assume you still have the "old" ECU? Maybe swap that back in. Also, I recommend you reach out to @BenzNinja who may be able to help remotely. He comes highly recommended.

MakUsa

Yes the original ECU is back in the vehicle
it runs the same with both of them

Chevota

I'd try giving it a full charge with a charger, and leave it on after you start it to see if it makes a difference. So you can rule out voltage... My car can run down in the low 11V range no apparent problems firing, and has dropped down in the 8V range on cranking, so for my car it doesn't matter but I have a different ECU. Mine seems to draw ~15A with the Ignition On, not sure if that drops when it's running. The point is I'd feed it enough juice so the voltage stays up no matter what. Or just tie it to another running car, like jump starting, but leave it connected the whole time.
Not sure if you looked but there is a spot in Xentry to see the charging cycles. Not sure how useful that would be in this case, but you can see if it looks ok or a disaster. There is also a spot to see the estimated load on the alternator, live.
Then there's the low idle, which seems weird to me because it should try to maintain correct rpm. Since the power drain is high at idle, and the alternator has trouble at lower rpm, voltage may be low simply because of that. Or perhaps you have a power drain, something stupid, and that combined with low rpm is causing the low voltage. This is where an exterior charge source will help.
There's also a spot for misfires, which I'd assume shows misfires only and should not count if it the ECU pulled that cyl. I don't believe it would pull spark for any reason, ever, but may pull fuel for some weird reason. Still, if it didn't pull fuel and it didn't fire, it should be able to see it. Apparently it "sees" that by watching the crank sensor. If the crank is slightly slower moving in one spot it assumes a misfire. Maybe also looks at the O2 sensors, who knows. The compression test is similar, it looks for a cyl that is faster.
Idle is programming, not some screw setting on the throttle. So if it's low it makes me wonder how? How about posting an Xentry report showing all the crap wrong so we can maybe spot a clue to any of it.

Perhaps you already tried all this, because before I'd pull the head I would have exhausted every possible option. I could have the head off my truck in 30 min. My Benz, ugg, I think I'd rather have my feet over hot coals.

If all fails, I agree with the BenzNinja suggestion. I tend to have issues (with all things) that nobody has ever seen or knows how to fix, which is why I signed up with him.
Not sure what laptop you have your Xentry on, but hopefully not one the chinese talked you into? I used an existing laptop and just swap the hard drive out between normal and Xentry use.
Originally I had a $50 chinese copy of Xenty, but it was a pita. It was always complaining about some aspect of the hack and I'd have to redo it every time I used it. The BenzNinja version just works, plus it has Vediamo and Monaco and they work. No hassle, just works.

MakUsa

Thanks for the advice,
Next time I work on it I will focus on the voltage/alternator/battery and post the results.

CaliBenzDriver

When suspecting your alternator, consider voltage study longer than 40mn or more (daytime without A/C load).
Poor voltage control is external from ALT. Replacing it will confirm that ✌️

S-Prihadi

Ok. I never met anyone with Autologic on MB Forum....nice.
Hope someday you can share some info on Autologic.

BlackML550

A quick one - Why did you need to change the ECU?

S-Prihadi

With Xentry and a 4 channels pico automotive scope + 2 low current clamps and some hard work because of your airbox, you can see which one went "bad" first, Ignition or Fueling.
I don't envy M276.9 3.5NA air box when doing troubleshooting ignition, fuel injectors and engine breathing.
It is so pain in the azz by design for us to troubleshoot ( based on photos if for me ), as no M276.9 was introduced in my local market, they jump to M276.8 3.0 Turbo from M272 3.5 or 3.0
For my country, in 2009, engine with higher than 3.0 liter displacement, there will be luxury sales tax like 40% or so , hence that strategy of engine choice MB took.

Mine is easier M276.8 3.0 Turbo as my air box is purely airbox and not part of intake manifold like M276.9 3.5NA
I feel your pain

M276.9 being a MAF engine, the airbox vacuum hoses & PCV hoses and if one get loose ENOUGH, it will cause bad idle and distract you from your initial troubleshooting
Mine because of a turbo version, uses MAP ( speed density as US tech likes to call ).

,

S-Prihadi

Because he suspected the ECU cylinder 1 ignition trigger went bad.
If for M276 this is usually not the case because of we use smart COP self powered, but for M272 with ME9.7 or M271, where both ECU are the power source of the COP and uses dumb COP,
ECU COP trigger-power semiconductor went bad is a common problem.

Dave Backmarker

JettaRed, Without a doubt, a bad battery will kill the alternator as the battery is putting a large constant current draw the alternator must produce. I liked your checklist above. The flickering dome lights indicated to me an alternator - vol at age regulator issue.

My son had a 1998 Red Jetta. We pulled the engine five times. He had the car for seven years and won a second place at Water Fest. He learned a lot about working on cars with that car and he and I spent countless and precious father-son hours under his red Jetta. Whenever I see a red Jetta, Imthink back to those days.

MakUsa

You suggesting replacing the alternator?
Or first battery?

MakUsa

I was just wanted to eliminate the ECU from my troubleshooting.
Same issues with different ECU and I moved on to different areas.