M271 Engine Rough Idle and Misfire Codes P0301-303, P0325 Knock Sensor, P0341 Cam Position Sensor

W21

New Member
Joined
May 11, 2020
Messages
6
Location
Dublin, Ireland
Car
Mercedes C180K 2006 W203 M271
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
 

DSM10000

MB Enthusiast
SUPPORTER
Joined
Jul 12, 2011
Messages
9,283
Location
Near Salisbury
Car
E32O CDi Sport, MX5 1.8 Sport, Range Rover 5.0 SC
This engine is well known for wear on the camshaft sprockets, guides and timing chain. the chain may well have jumped position on the sprockets throwing out the timing, in some cases this can lead to bent valves.

Get it towed to an MB Specialist and let them take a look.

In the interim I would not try to start it.
 
OP
OP
W

W21

New Member
Joined
May 11, 2020
Messages
6
Location
Dublin, Ireland
Car
Mercedes C180K 2006 W203 M271
@DSM10000 - Thanks for responding so quickly.

Ouch, that sounds pretty horrendous. Is it possible that it can jump a single tooth and not totally ruin the engine. I would have thought a single tooth out would mean the piston and valves smashing together and total carnage.

Thx
 

DSM10000

MB Enthusiast
SUPPORTER
Joined
Jul 12, 2011
Messages
9,283
Location
Near Salisbury
Car
E32O CDi Sport, MX5 1.8 Sport, Range Rover 5.0 SC
@DSM10000 - Thanks for responding so quickly.

Ouch, that sounds pretty horrendous. Is it possible that it can jump a single tooth and not totally ruin the engine. I would have thought a single tooth out would mean the piston and valves smashing together and total carnage.

Thx
Yes it can just jump a tooth and not cause piston /valve damage just rough running. There are quite a few possibilities on this engine to account for the symptoms so rather than guess I would recommend getting it to a specialist for a proper diagnosis.
 

markjay

MB Master
SUPPORTER
Joined
Jun 24, 2008
Messages
37,434
Location
London
Car
W204 C180 Executive SE 2013 Automatic / COMAND NTG4.7 and Morel speakers fitted by www.comand.co.uk
As above.

If you are very lucky, there was no piston-to-valve contact yet, and a new timing gear kit comprising of two new camshaft sprocket wheels, timing chain, guides and tensioner will sort it out (around £1,500 to £2,000 parts and labour from a specialist).

Apart from the issue with the timing gear, the M271 is a strong engine and once the timing is fixed it will serve you well for many years to come.

If, however, the pistons did hit the valves, then then engine will need (in addition to new timing gear kit) at least a number of new valves, plus most likely new pistons (there are 16 in total, typically 4 or 8 new valves will be needed), and possibly even new con rods - whicj means that the engine is beyond economic repair on a car of this age.

As for buying a second-hand engines... they are few and far between, and for a good reason. And at any rate before fitting a second-hand engine you'd want to change the timing gear, so not a cheap exercise overall, even if you do manage to find one for a reasonable price.

I suggest that you wait until after the COVID-19 lockdown is over, and then get the car recovered to a specialist.

Once they take off the cam cover they will be able to tell if there's an issue with the timing gear. Once the chain is back in place, a simple compression test will show if there are any bent valves, or they van use a borescope to inspect the condition of the piston and valves.

And, if you are lucky, the issue might not be with the timing gear but something else more simple, or alternatively the timing gear will need replacing but the valves will prove to be undamaged.

In any case I would not start the engine again - it could end-up being the difference between fixing the car and scrapping it.
 

markjay

MB Master
SUPPORTER
Joined
Jun 24, 2008
Messages
37,434
Location
London
Car
W204 C180 Executive SE 2013 Automatic / COMAND NTG4.7 and Morel speakers fitted by www.comand.co.uk
The other known issue with the M271 engine is leaking camshaft position sensors, with the oil climbing-up the loom into the ECU, an issue that you seem familiar with.

In this case the car will need a new loom, and possibly either a new ECU or have the existing ECU repaired by someone like Home (GB) | BBA Reman .

This will be a cheaper fix compared to the damage from timing gear failure.
 
OP
OP
W

W21

New Member
Joined
May 11, 2020
Messages
6
Location
Dublin, Ireland
Car
Mercedes C180K 2006 W203 M271
As above.

If you are very lucky, there was no piston-to-valve contact yet, and a new timing gear kit comprising of two new camshaft sprocket wheels, timing chain, guides and tensioner will sort it out (around £1,500 to £2,000 parts and labour from a specialist).

Apart from the issue with the timing gear, the M271 is a strong engine and once the timing is fixed it will serve you well for many years to come.

If, however, the pistons did hit the valves, then then engine will need (in addition to new timing gear kit) at least a number of new valves, plus most likely new pistons (there are 16 in total, typically 4 or 8 new valves will be needed), and possibly even new con rods - whicj means that the engine is beyond economic repair on a car of this age.

As for buying a second-hand engines... they are few and far between, and for a good reason. And at any rate before fitting a second-hand engine you'd want to change the timing gear, so not a cheap exercise overall, even if you do manage to find one for a reasonable price.

I suggest that you wait until after the COVID-19 lockdown is over, and then get the car recovered to a specialist.

Once they take off the cam cover they will be able to tell if there's an issue with the timing gear. Once the chain is back in place, a simple compression test will show if there are any bent valves, or they van use a borescope to inspect the condition of the piston and valves.

And, if you are lucky, the issue might not be with the timing gear but something else more simple, or alternatively the timing gear will need replacing but the valves will prove to be undamaged.

In any case I would not start the engine again - it could end-up being the difference between fixing the car and scrapping it.

Markjay, thank you for your response. I plan to take off the rocker cover and turn the engine to TDC and see if the chain has jumped a tooth and the cam markings no longer line up. Once i have established this i can then consider moving the chain/gear back in line and then test compression.
 

markjay

MB Master
SUPPORTER
Joined
Jun 24, 2008
Messages
37,434
Location
London
Car
W204 C180 Executive SE 2013 Automatic / COMAND NTG4.7 and Morel speakers fitted by www.comand.co.uk
Good plan, but make sure you rotate the engine very gently (with the spark plugs removed to reduce resistance to rotation), and stop if you get any form of resistance that may suggest that the valves are hitting the pistons (even after the timing markings and chain have been realigned).

In the event that the issue turns-out to be a failed ECU due to engine oil ingress, and not an issue with the timing gear, you should still consider replacing the timing gear preemptively, given the car's mileage (100k).

And, on a general note, make sure that the car is serviced regularly using engine oil that meets 229.3/229.5 spec. It won't completly remove the risk of timing gear failure, but it will help reduce it.
 
OP
OP
W

W21

New Member
Joined
May 11, 2020
Messages
6
Location
Dublin, Ireland
Car
Mercedes C180K 2006 W203 M271
Okay, sorry for the delay in responding, 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 again and thanks in advance for any replies Cam1.jpg Cam2.jpg Cam3.jpg
 

Petrol Pete

MB Enthusiast
Joined
Nov 11, 2016
Messages
7,324
Location
Petrol stations ...everywhere
Car
C55 AMG Wagon
The cam sprocket on the right is completely fooked the one on the left is on it's way out i'm afraid . new sprockets , chain and tensioner guides required...minimum :(
 
OP
OP
W

W21

New Member
Joined
May 11, 2020
Messages
6
Location
Dublin, Ireland
Car
Mercedes C180K 2006 W203 M271
The cam sprocket on the right is completely fooked the one on the left is on it's way out i'm afraid . new sprockets , chain and tensioner guides required...minimum :(

Would you replace them just to run a compression test? I'm not wanting to spend all the money and time on the new sprocketcs, chain, tensioner etc if the cylinders and valves are knackered as i will probably just scrap the car. I was hoping to part-x the car for a brand new one from a dealer. If the valves aren't bent then i just want to get the engine running and reasonable for trade in
 

markjay

MB Master
SUPPORTER
Joined
Jun 24, 2008
Messages
37,434
Location
London
Car
W204 C180 Executive SE 2013 Automatic / COMAND NTG4.7 and Morel speakers fitted by www.comand.co.uk
I don't think anyone can answer your question with any degree of confidence.

Replacing two camshaft sprocket wheels, chain, tensioner ans guide will cost - I am guessing - £600-£800 in parts? A bit much, given the uncertain outcome.

You can decide to take a chance and give it a go, i.e. adjust the timing without replacing anything and run a compression test. . If the engine proves to be damaged, you'll never know if it was like that before, or you fooked it during the compression test...

Or, how about this: remove the cylinder head and check the valves and pistons. If there's internal damage, it's curtains. If the valves and pistons are fine, the exercise will cost you a new head gasket kit (I am guessing ~£100?) and a couple hours of your labour. But at least you will be playing it safe.
 
OP
OP
W

W21

New Member
Joined
May 11, 2020
Messages
6
Location
Dublin, Ireland
Car
Mercedes C180K 2006 W203 M271
I don't think anyone can answer your question with any degree of confidence.

You can decide to take a chance and give it a go. If the engine proves to be damaged, you'll never know if it was like that before, or you fooked it during the compression test...

Or, how about this: remove the cylinder head and check the valves and pistons. If there's internal damage, it's curtains. If the valves and pistons are fine, the execrise will cost you a new head gasket kit (I am guessing ~£100?) and a couple hours of your labour. But at least you will be playing it safe.

The voice of reason eh markjay. I guess that makes the most sense. I think as i get older i lose confidence in my ability but the head change isn't that tougher job is it?

Move crank to TDC on cylinder 1 with cam lobes on exhaust and inlet pointing up on cylinder 1
remove power steering pump and alternator out of the way
wind out the chain tensioner
Drain coolant
take off timing chain from cams and hang up out of the way
remove cam covers
undo head bolts in outward circle
Is that it?

Will need to replace head bolts and gasket on putting it back together if all okay?

Is it really that simple? Am i missing anything

BTW - Anyone got the WIS or PDF i could steal/borrow/beg?
 

Users who are viewing this thread

Top Bottom