Hey there,

First of all, I want to say hi, I've been on the forum as a visitor from the moment I got my 2016 C63 AMG more than a year ago

I am kindly coming to you with a problem that I am facing right now

Two weeks ago, my car started randomly jiggling and threw a CEL: The car worked after being turned off and then on again, but it would start to do the same after a while and after acceleration.

I went to the dealer, they replaced all my spark plugs + the bad coil (they said it was cracked).

The bad coil had also a very bad spark plug that didn't even have a tip anymore.

After this, it worked perfectly smooth for about 125- 175KM, and then it threw a CEL again

Now, I am back at the dealer with the car and they did a compression test (they said the compression is good) and told me the spark plug is f*cked again

They think its the injector, but they can't really tell me for sure

I would highly appreciate it if you could share some info if someone has been through this, as I do not really know what to do moving further

Thank you very much!

PS: the car is stock

 

******Sounds like it could be a bad injector as well as a crummy and/or lazy mechanic unable to properly diagnose or at least do basic service field tests of the injector while still on the rail. The injector can at least be tested somewhat for egregious or obvious failure with an electronic injector tester. This is very commonly done on race cars or other such vehicles without individual cylinder EGT's or wide band O2 sensors. It is NOT definitive, but it does spot sticky or possible poor or limited spray pattern issues while the injector is still on the fuel rail and in the car. Definitive diagnosis requires the injector be removed and flow tested for volume as well as spray pattern based on a known fuel pressure and injector pulse duty cycle.

Pic below of an on car injector tester, NOT for Mercedes Benz, but for one of my race cars. The purpose of the funny looking box is to provide artificial known pulsewidth so a mechanic can "hear" an obviously sluggish or faulty/dead injector. It works off 12 volts and the injector connector is disconnected and the testers leads are hooked up with the car OFF (duh) and pulsed through various cycles. Continuous mode allows for quickly diagnosing outright bad injectors, pulse modes allow for various millisecond pulses to click the injectors on and off and by testing a couple of other injectors one can quickly "hear" a difference based upon pulsewidth sounds on "good" or "working" injectors. A mechanic can do 1, 50, or 100 pulses and "hear" whether the injector sounds ok. No fuel pressure is tested, nor spray pattern, this is strictly to test the injector duty cycle and changes to such, electronically.

If in doubt, replace the injector, which on our cars is kind of a PITA, but doable and reasonably cheap to do if this is the problem, versus just replacing spark plugs, coils, or whatever in the *hope* you solve the problem.

Anyway, good luck, and always remember it is easier for a mechanic and the profitability of the dealer or business to just start replacing *expensive* parts and hope things get fixed versus proper diagnosing and narrowing down of a relatively simple problem IF the mechanic is more than just a technician, and understands more than just what a scan tool might tell him is possibly wrong from a code. The codes can help narrow a problem down, but it takes some thinking to sometimes find and fix a seemingly intractable problem.

MAX

 

Thank you very much for taking the time to reply.

When they were talking to me about this, they were mentioning that they do not have the tool to endoscopically test and check the injector (they didn't mention any electronic tester)

I live in Romania & I went to an authorized dealer all the time to make sure things are done right, but I can see that they are used to just "basic" things in there and "bored" looking.

Not sure if I should just tell them to order the injector and go fo it or try and find another mechanic.

 

I would just replace the injector. Grab the special tools and a scanner tool to input the injector serial number and you’re good.

We need more diy anyways since there are very few AMG owners who work on their cars.

 

*****THIS.

 

I agree and others knock them down with dumb comments

 

I’m lost lol was my comment positive or negative?

 

nah bro, not a swipe at you lol i'm saying in the threads I create or that other's create

got these guys saying stuff like 'don't get a tune, don't do this, don't do that" instead of giving real advice or insight

 

right on lol I was wait.. what did I say? Haha

but yeah I’m with you on that. 🤘🏽

 

Btw my car is stock also.

the scanner I got it from Amazon for $300 and I’m sure the injector installation tool itself is around $100. It’s a simple jig to install the rings around the tip of the injector.

I’m planning on buying that Tool myself soon just in case.

 

Any chance you regularly run an ethanol blend?

 

A lot of work to do actually what the dealer told u about it !

 

Welcome to the forum. Which cylinder(s) are misfiring for you? Also did you notice your ECO start stop green light on the center console unavailable?

 

Hey everyone!

Coming here with an update after I decided to replace the injector

Been driving it for 200km+ after the change and it seems that my problem went away, so it was definitely the injector in this case

Thank you to everyone who replied!

 

Good. Which cylinders were misfiring before the injector was replaced?

 

What scan tool did you use to code the Injector?

 

Now that its running well, you can maybe find yourself a new shop.