Blackrock63

Mercedes C180K - 2006 (W203)
Engine M271
100,000 miles

My C180K will not start and if it does it sounds like a diesel tractor and runs rough. Can anyone help me detect the reason because due to Covid 19 i can't take it to a garage and i need the car to use to shop etc.

It all started the one morning when the car started up fine but had a rough idle. I could rev the engine cleanly but it would idle rough. I took the car on a drive and it was fine on the motorway for 30 miles but it still idled roughly when stationary. I then made the return journey about 2 hours later and the car ran fine again but still had an idle issue. Once i had reached my destination i tried to start the engine again about an hour later and the engine ran really badly and sounded like a diesel tractor so i immediately turned it off. I used my handheld code reader and got teh following codes:

P0301, P0302, P0301, but not P0304 All codes are listed as Cylinder Misfire Detected
P0325 - Knock Sensor 1 Circuit Bank 1 or Single Sensor
P0341 - Camshaft Position Sensor A Circuit Range/Performance Bank 1 or Single Sensor

I have replaced the Camshaft Position Sensor with a new one thinking that was the issue but the problem still exists

I called the roadside recovery company (AA Ireland) and they called out. He tried to start the engine but couldn't get it started. He took out all of the plugs and visually inspected them and none of them were damp or showed particular signs of wear. He tried to start the car again and he managed to get it started and but it was running really rough. He couldn't identify what the issue was and told me to take it to a garage and get them to stick it on their machine.

I do have very oily camshaft magnets. I took them off and cleaned the oil away. There was a trace of oil on one of the terminals which i have cleaned. I traced the wires back to the ECU and there was a small amount of oil at the end of a lead but i can't be sure if this is the camshaft magnet lead. I have seen online that i can test the magnet by attaching a 12v battery and placing an electrical meter inline to the magnet and then by moving a metal spanner around the magnet i should be able to see if the magnet generates a signal. I haven't done this yet but will try to do it next. I have no idea how to test the leads though so if someone can advise on testing that the leads to the magnet give a signal/volt then i would love to hear from you.

So basically, can anyone help diagnose my non-start and rough idle. I don't want to keep replacing potential problem parts with new ones as i don't have much spare cash following Covid work restrictions.

Thanks in advance for any help you guys can provide

Blackrock63

Okay, sorry for the delay in posting, work has been very busy this week!!

I spent time working on the car at the weekend and managed to access the cam chain - I wish i hadn't!!

As you can see from the images, the inlet cam has moved approximately 3 teeth over. You can see that the cam teeth look very worn, especially where i have marked in yellow. The exhuast cam teeth look okay in my humble oppinion. DO you think the crank teeth will look as good as the exhaust or as bad as the inlet? Also, the timing chain is very tight, hardly any movement when i try to lift the chain off the guide at the top which was a little encouraging!!

I tried putting down a basic endescope in cyclinder 1 and everything seems to be okay. I haven't looked at 2,3 and 4 yet as the video software i was using (VLC) made the video images very slow and delayed which meant it was too difficult to hold still at times to look around. I will try and find a software that works better and try again.

Here's my question - If i was to loosen the tensioner and move the inlet cam back to it's intended position and set the correct tension back to the tensioner, would it be safe to carry out a compression test by turning over the engine. I don't have access to a leak test, nor do i have a local garage i can get the car to. I plan to slowly hand crank the engine first to make sure there is no unusual resistance before i try a compression test. What's your views?

Thanks in advance for any replies

chassis

How do you know the chain has jumped teeth? Sorry for the basic question.

If you suspect the cams are misaligned, I would not do a compression test until you either properly reset the cam timing or definitively confirm the engine is a free-running design.

An expert on this engine needs to chime in. Try posting in the C-Class section appropriate for your vehicle.

This site doesn’t have good cross-forum visibility/collaboration and there are not sections for the more common engines, despite the admins having been requested to do this.

Blackrock63

Hi chassis,
The timing marks on the cams do not align to the casing markings. I counted that the intake cam is about 3 teeth further clockwise than the timing mark.

Thanks for advice on C Class Forum. I hadn't thought about that when i posted

chassis

Is this engine known for the cams coming out of time? The chain would have to come loose, then re-engage for that to happen. If it re-engaged, why isn't it continuously/permanently loose?