2005 C200 W203 Kompressor - Engine Falters On Slow Down

[garyreekie]

My car is a 2005 Mercedes W203 Kompressor with 90000 miles on the clock. Just recently a Mercedes Main Dealer has replaced the timing chain, timing tensioner, both camshaft adjustors, 16 hydraulic lifters and all the spark plugs.

Subsequent to the repairs the car is suffering with an intermittent problem whereby the engine falters on slow down. It feels as though the car is going to stall but has not done so as yet. The engine light has not come on nor has the onboard computer registered any faults. For awareness the alternator has recently been replaced as have all the vacuum hoses. Does anyone have any ideas why, subsequent to the engine repairs, the car is experiencing intermittent engine faltering on slowdown?

 

[ernieh]

My car is a 2005 Mercedes W203 Kompressor with 90000 miles on the clock. Just recently a Mercedes Main Dealer has replaced the timing chain, timing tensioner, both camshaft adjustors, 16 hydraulic lifters and all the spark plugs.

Subsequent to the repairs the car is suffering with an intermittent problem whereby the engine falters on slow down. It feels as though the car is going to stall but has not done so as yet. The engine light has not come on nor has the onboard computer registered any faults. For awareness the alternator has recently been replaced as have all the vacuum hoses. Does anyone have any ideas why, subsequent to the engine repairs, the car is experiencing intermittent engine faltering on slowdown?

Could be a number of reasons, but best to get it on STAR to have the codes read. Having spent that amount of money with them, I would hope that dealer who did the repair would cover the diagnostic costs.

ERnie

 

[LostKiwi]

I'd be taking it back and getting the dealer who did the work to sort it.

 

[garyreekie]

Could be a number of reasons, but best to get it on STAR to have the codes read. Having spent that amount of money with them, I would hope that dealer who did the repair would cover the diagnostic costs.

ERnie

Thank you ERnie. The car has been returned to the main dealer and STAR has identified no problems. The senior engineer has had the car for some time now and has not been seen any evidence of the intermittent engine faltering on slow-down. Could any of the work undertaken when replacing the timing chain, timing chain sensor and the 16 hydraulic lifters cause such a problem; the car did not have this intermittent issue prior to the repairs?

 

[garyreekie]

Thank you ERnie. The car has been returned to the main dealer and STAR has identified no problems. The senior engineer has had the car for some time now and has not been seen any evidence of the intermittent engine faltering on slow-down. Could any of the work undertaken when replacing the timing chain, timing chain sensor and the 16 hydraulic lifters cause such a problem; the car did not have this intermittent issue prior to the repairs?

 

[umblecumbuz]

Have they checked simple things, like spark plug gaps and conformity - which would affect engine smoothness but would not show up as a fault?

Sounds like a bit of bedding in or fine tuning is all that is needed here.

 

[Arudge]

I'd be taking it back and getting the dealer who did the work to sort it.

Me too.

The only thing i can think of is the cam timing, it's not quite where it should be.

 

[umblecumbuz]

Me too.

The only thing i can think of is the cam timing, it's not quite where it should be.

If it was cam timing, would that produce an intermittent fault, and on deceleration only?

 

[LostKiwi]

If it was cam timing, would that produce an intermittent fault, and on deceleration only?

Possible if it's staying advanced then suddenly returning if it sticks.

 

[Arudge]

If it was cam timing, would that produce an intermittent fault, and on deceleration only?

Incorrect cam timing does all sorts of strange things. On mine, the exhaust cam was 15 degrees retarded and it caused misfire. I still can't get my head around it but it did. We all know that advancing the inlet cam too much will cause a lumpy idle, and the OP has stated that the engine feels like it's going to stall, but it hasn't yet.

We all like to think the experts know what they are doing, but i have my reservations.

My brother had an Audi serviced including a timing belt, came back belching smoke. Cam timing was wrong.

A friend had a Subaru serviced including a timing belt, came back with a lumpy idle and no bottom end power. Guess what? Cam timing was wrong.

It's not easy timing a cam, it's not just a case of line up the marks and off you go, there are tolerances. When i set mine up the marks didn't line up perfectly, it was mid tooth. So i had to move it to the nearest tooth. The inlet cam should be set at 20 degrees but i couldn't get 20 degrees, so i went for 23 degrees. But when i rotated the crank one full turn i realised i had gone the wrong way and i'd got 17 degrees, which is not acceptable. 23 degrees IS acceptable.

Very easy to get it wrong, and how many people check their work? Especially when the gaffers saying the customers waiting.

 

[Arudge]

There are two mantras in my trade.

If in doubt, ask.

And.

Check it twice, cut it once.

I make a good living mopping up other peoples mess. They just don't think.

 

[Steve@Avantgarde]

Cam timing would produce fault codes for sure. These engines always do. As would a misfire of any kind. It is impossible to mistime these engines as there are locking tools to hold the cams in position, you can't do the job without using the tools either.

I have had the kompressors break up on the pulley spindle causing erratic air delivery.

 

[Arudge]

Possible if it's staying advanced then suddenly returning if it sticks.

Absolutely, the whole idea of those devices is to give you a smooth and refined idle and a bit of extra umph when the RPM is high enough to take the advance. But if it's sticky........

 

[umblecumbuz]

Hmm. Two opposing viewpoints here.

It will be enlightening to find out from Gary what the final answer is.

 

[Arudge]

Cam timing would produce fault codes for sure. These engines always do. As would a misfire of any kind. It is impossible to mistime these engines as there are locking tools to hold the cams in position, you can't do the job without using the tools either.

I had no codes for my cam timing errors. Admittedly i didn't use STAR, i have Carsoft. And with the 5mm pegs in place the two cams lined up with each other, but were 3 degrees out at the crank. But of course, i was using the crank as the datum and bring the cams to the datum, it doesn't work. How many others have tried that, and not noticed that they have pulled the crank round to make it fit? Or worst still, they've lost the proper dowels and used a rivet or whatever they can lay their hands on, or just guessed?

I agree, it's impossible to get it wrong if done properly. It's the being done properly that i'm challenging.

 

[Arudge]

Just to illustrate some of the bodgery that goes on.....

In this clip watch very closely from 2.10 minutes in. Here, our presenter checks the cam timing with a peg. We'll forgive for using a Torx bit for now. The peg needs to pass through 3 holes, two in the casting and the third in the cam wheel, when all three line up we know we're in the right place.

Watch carefully as he tries the exhaust cam first, note how far the peg goes in. Note how far the peg goes into the inlet cam, at least another 6-8mm.

Watch it again.

Despite the fact the peg is very undersize it's clear he hasn't found the hole in the exhaust cam wheel and the timing is not where it should be, despite his claims of 'this is how you do the proper timing'.

 

[garyreekie]

My sincerest thanks to you all for your contributions to date. My dilemma at present is that subsequent to the recent repairs I have lost all confidence in my car due to the intermittent nature of the engine 'faultering' on slowdown and the fact the car is not registering any fault whatsoever which can be diagnosed by STAR. Also a senior Mercedes engineer has undertaken a number of test drives and has not encountered any problems; the car is currently with the same Mercedes senior engineer for further test drives.

For awareness my 86 year old father is currently unwell and lives some distance from me. Due to his frail health I need to visit him more regularly and as such I need a reliable car; it was for this reason I asked Mercedes to fit a new timing chain as this was the only known issue with my car in terms of its' reliability.

I will be speaking with the Mercedes Service Manager on Monday and will relay all the information you have kindly passed on. However, as you are all far more experienced in the workings of a Mercedes engine and all its' components have you any further advice and guidance in terms of what I can expect from the Main Dealer? In my own humble opinion my car entered the Main Dealer to determine whether the timing chain needed replacement which it did. I subsequently authorised the timing chain replacement and took the opportunity whilst this was being undertaken to have the 16 hydraulic lifters replaced as some were noisy. As you are now aware the car has subsequently developed an intermittent problem and as such do I have a right to insist upon the problem being diagnosed and fixed prior to my car being returned to me despite no fault codes being identified on STAR and the senior engineer not having experienced the issue when undertaking test drives?

In conclusion the Main Dealer's Service Manager has been most helpful to date and I have a loan car, however, this is the second time the car has been returned to them and I am concerned that should the problem not be encountered whilst on a test drive they will try to return my car with the problem undiagnosed. Should Mercedes be unable to find the fault can I insist on the repairs being totally undone and then undertaken from scratch once again with new parts? Prior to the repairs I had a very good idea what was wrong with my car in terms of reliability, now some 2 months later and a few £0.00's poorer I have an undiagnosed reliability issue which is deterring me visiting my father.

 

[LostKiwi]

Should Mercedes be unable to find the fault can I insist on the repairs being totally undone and then undertaken from scratch once again with new parts?

Unfortunately not.

How intermittent is the issue?

 

[Arudge]

My dilemma

You have my utmost sympathy, but as issue refuses to show itself there's little that can be done.

Although we would all look to what's changed or worked on to try and resolve an issue, I'm beginning to wonder if this is engine.

Could it be transmission?

I had an issue with my transmission that only occurred on downshift, I would describe it as transmission wind up, had a lumpyness to the lower gears and almost felt like the car was being pushed as we decelerated. I've also heard it described as knotty. Could this be your faltering? In my case it was a faulty sprag bearing at 107,000 miles. No codes on STAR. Took me months to track it down.

Just a thought.

 

[Steve@Avantgarde]

Just to illustrate some of the bodgery that goes on.....

In this clip watch very closely from 2.10 minutes in. Here, our presenter checks the cam timing with a peg. We'll forgive for using a Torx bit for now. The peg needs to pass through 3 holes, two in the casting and the third in the cam wheel, when all three line up we know we're in the right place.

Watch carefully as he tries the exhaust cam first, note how far the peg goes in. Note how far the peg goes into the inlet cam, at least another 6-8mm.

Watch it again.

Despite the fact the peg is very undersize it's clear he hasn't found the hole in the exhaust cam wheel and the timing is not where it should be, despite his claims of 'this is how you do the proper timing'.

This is a 111 engine and the op has a 271.....

A 271 engine has a special tool that locks the twin camshafts in position together, when this tool is in situ, the cams cannot move. There are 2 timing marks at TDC on each cam that lines up on the cylinder head also. The bit I can't remember right now is whether the crank is at TDC or at 40' post TDC as Merc use both positions for timing on different engines, but that is irrelevant to the discussion right now.

Either way, if the cam timing is incorrect when it advances or retards the cam position must hit spec and actual value, if not the engine ECU will see it as a mis-time, it will then try and adjust the cams to suit and record its fault data. With STAR you will also be able to see this in its actual value function chain.

271's also log self adaption fault codes which is linked to timing in as much as when the cams fail to hit spec value for position and the cams advance/retard to try and correct it effects it's emissions running. In the early days this caused a bump steer for correct diagnosis as main techs went down the emissions path looking at air trim values from the MAF's and leaks from the air system (as per the guided diagnosis steps on star) and failed to find or fix the fault. No if we see no leaks on a charge air pressure test via the air box then its rocker cover off for a check of the timing.

Given that the op has had the work carried out at the main dealer I would expect them to have the special tools and use them. Like I said previously, I don't think you can successfully do the job with out them.