[West]

You are correct, removing the fuel rails is not a fun job, with that said it is not super hard or technical. You just need to plan for it to take 4-5 hours and be patient. You will need to make a platform so you can work while looking down at the rear of the engine. I did it once with a piece of plywood and a few more times with a TOP CREEPER, the Top creeper allows you to lay on a padded support looking down at the job with both hands free to work. I am 66 and could not do this job without the ability to lay down above while working, a much younger guy may not need this tool. The High Pressure fuel pump and the protective metal shield behind it take quite a while to remove the bolts using a combination of tools, sockets, wrenches and extensions, a couple of these bolts will take 1/2 hour or more each, do not think it will go fast. Take pictures so you know where all the lines bolt down and how the lines and HPP shield align. If your tool selection is limited this is not a good job to tackle. You need to buy the socket for the cam adjuster bolt, it is unique and a variety of Torx wrenches, sockets both male and female are needed. I have some with built in swivels that were used. Some of the bolts are very hard to reach and space is limited. Install can be harder than removal..
Keep exact tract of where each bolt comes from as they are not all the same. To save time I put the bolts from each part removed into a plastic sandwich bag and mark where they came from and if needed where specific bolts go, some are only 1/4" longer than others but have a specific home, this helps save time on install. Aligning the cams has to be done exactly right, no wiggle room.
Check to make sure the cam timing wheel has not slipped on the cam. When cam adjusters fail the timing wheel can move a little and cause check engine lights.
I have moved one back by forcing it to rotate to original position. That one is still running fine now that the broken cam adjuster was replaced and it is no longer banging on start up. Some say you must buy new cams to fix this issue. I cheated, it worked so far. I believe the broken cam adjusters banging on start up makes the position wheel slip on the cam. That is my thoughts and I may be 100% wrong? The wheel is just pressed on with nothing but friction holding it in place.

 

[pine1000]

Is there a way to 100% confirm that the cam adjuster is bad? I saw a video where the engine is spun by hand and you can see the cam adjuster slip and spit out some oil. Mine doesn't do that, I've marked it and spun it many times and mine doesn't jump.

 

[West]

Did you check both banks when you did this? I had one that I was positive was on one bank, turned out it was on the other bank. Did one that had one bad adjuster on each bank. As you crank it over, It takes 2 revolutions of the crank to really see it jump. It will make a pretty loud snap noise when the adjuster jumps and your lines will no longer line up. In this video at 37 seconds in you will hear the click or snap noise when the adjuster moves when it should not. Watch a few times you will hear it clearly. I have seen a video that shows it move as it snaps but I could not find that one.

 

[pine1000]

I did mark and check all four cam adjusters after I put in the new tensioners. The marks never got out of sync and I did spin the engine over at least 3 times probably a lot more than that. The thing that I find strange is the startup rattle is gone after the tensioners but now I have the P0021 and didn't have that before.

When the solenoid is engaged does that cause the cam timing to be retarded or advanced? It's wishful thinking but I want to make sure that current is getting to the solenoid.

 

[Deplore]

https://www.benzworld.org/threads/m276-camshaft-adjuster-replacement.3098923/page-2?post_id=18505948#post-18505948

If you have rattling noise on start up, it is 100% adjuster. Keep spinning. You want to do at minimum 12 full engine rotation. Ideally more.

 

[pine1000]

https://www.benzworld.org/threads/m276-camshaft-adjuster-replacement.3098923/page-2?post_id=18505948#post-18505948

If you have rattling noise on start up, it is 100% adjuster. Keep spinning. You want to do at minimum 12 full engine rotation. Ideally more.

I had the rattle on startup with no CEL, after doing the tensioners I no longer have a rattle but I do have a CEL with P0021.

 

[Deplore]

Long crank?

 

[West]

Deplore is asking if it starts quickly when you turn the key or does it crank a lot before finally starting. Not what you want to hear but it sounds like one of your cams is off time.

 

[pine1000]

Deplore is asking if it starts quickly when you turn the key or does it crank a lot before finally starting. Not what you want to hear but it sounds like one of your cams is off time.

I have noticed a few long cranks. By off time, do you mean the reluctor wheel shifted or the the cam gear is out of time with the crankshaft?

I did not have the crank in the right position when I changed the driver's side tensioner and had some problems getting it out. So, it is possible that the chain could have jumped. However, looking through the CPS holes things seem to be aligned. These are the intake CPS on passenger vs driver side.

 

[West]

It has been a while since I looked at the timing marks but I recall one side reads on the forward edge of the reluctor wheel and the other bank reads on the trailing edge of the reluctor wheel? Again, going by memory. So one wheel is leaving the window and the other is entering the window. Found this picture, but verify it is correct before wrenching.

When the computer does not like the reluctor wheel positions your car will start hard. When they are in proper position the car starts on the first touch of the key.

I hope I am wrong but it does sound like the timing is off.

 

[peterjmdr]

I have noticed a few long cranks. By off time, do you mean the reluctor wheel shifted or the the cam gear is out of time with the crankshaft?

I did not have the crank in the right position when I changed the driver's side tensioner and had some problems getting it out. So, it is possible that the chain could have jumped. However, looking through the CPS holes things seem to be aligned. These are the intake CPS on passenger vs driver side.

View attachment 2895928
View attachment 2895927

Can we see the exhaust reluctor wheel positions through the CPS bores. Also what is your crank setting? You should be at 53 degrees after TDC/ ignition for these reluctor wheel photos. Here is another WIS image for proper reluctor wheel positions when the crank is set at 53 after TDC ignition:

 

[pine1000]

Can we see the exhaust reluctor wheel positions through the CPS bores. Also what is your crank setting?

I haven't opened the exhaust CPS bores, but I will do that this evening.

 

[pine1000]

The timing on bank 2 (driver's side) where I am getting the P0021 seems good to my eye.

Here are the intake and exhaust with the crank at 53

I think my next step might be to mark all of the adjusters with the paint pen and then reassemble everything. Find a way to make sure current is actually getting to the solenoid for bank 2 intake. Assuming that's not the problem, I will take it for a drive and then remove the solenoids and see if any of the adjuster have shifted.

Not sure I have the time to learn how to change a cam shaft. So, I'm also mentally preparing myself to pay a shop between $5k to $7k. Is that what I am looking at?

 

[rnettleship]

Take it from me, take it off first. You can do what you like, but if you don't properly install the adjusters correctly, you will bend valves. Camshaft WILL move as soon as the timing chain is out.

I completed the job last week and did take the valve cover off. I drove it around town for the week and went on a 700 mile round trip with no issues. No codes, ran like new. My wife takes it out today and within 10 miles it has no throttle response. Turn it off and on a few times so it would run well enough just to get it home. I have dozens of DTC's which leads me to believe this is an electrical issue at the ECU. The main battery has 12.5 volts with engine off and voltage at the ECU is 14v when running. I did have a bad aux battery and changed it but I did not have much hope that would effect the engine operations. The car will start and run but is smells very rich and the trans shifts haphazardly. Here is a short list of the DTC's it has now. I took a look at the main electrical connections I touched and did not see any connectors loose and the ECU plugs are fully engaged. Any suggestions on where to look first?

DTCs: 26
----------------------------
P0016 [0x0016]
Crankshaft position/camshaft position, bank 1 sensor A - correlation
Status: Confirmed
----------------------------
P0641 [0x0641]
Sensor reference voltage A - open circuit
Status: Confirmed
----------------------------
P061A [0x061A]
Engine control module (ECM), engine torque - performance problem
Status: Confirmed
----------------------------
P2227 [0x2227]
Barometric pressure (BARO) sensor - range/performance problem
Status: Confirmed
----------------------------
P2279 [0x2279]
Intake air leak
Status: Pending
----------------------------
P2179 [0x2179]
System too lean off idle, bank 2
Status: Pending
----------------------------
P2177 [0x2177]
System too lean off idle, bank 1
Status: Pending
----------------------------
P2188 [0x2188]
System too rich at idle, bank 1
Status: Pending
----------------------------
P2190 [0x2190]
System too rich at idle, bank 2
Status: Pending
----------------------------
P0641(04) [0x064104]
Sensor reference voltage A - open circuit
Status: Test failed, Test failed (current drive cycle), Pending, Confirmed, Test failed since last DTC clear, Warning indicator requested

 

[Deplore]

Unplug ECU connector (both of them) and check for oil contamination. Known issue.

Oil contamination comes from these item:

Camshaft sensor(s)
Camshaft adjuster solenoids
Oil pressure solenoid

 

[Deplore]

So, I'm also mentally preparing myself to pay a shop between $5k to $7k. Is that what I am looking at?

My ballpark for a single camshaft and adjuster is 2.5k, parts and labor. Add 1k for each additional camshaft + adjuster.

Now, this is Los Angeles pricing. May need to call around to find out, but 5-7k is engine replacement price.

 

[rnettleship]

Unplug ECU connector (both of them) and check for oil contamination. Known issue.

Oil contamination comes from these item:

Camshaft sensor(s)
Camshaft adjuster solenoids
Oil pressure solenoid

Am I looking for oil that finds it way up from the sensors to the ECU? I did look at the two ECU connectors and sprayed them with electrical contact cleaner. If this is happening, how would I correct it? Also, I do have the oil pressure solenoid disconnected.

 

[pine1000]

My ballpark for a single camshaft and adjuster is 2.5k, parts and labor. Add 1k for each additional camshaft + adjuster.

Now, this is Los Angeles pricing. May need to call around to find out, but 5-7k is engine replacement price.

That's encouraging. I called Mercedes of South Charlotte about the tensioners and the service advisor quoted me $5k and said they always replace the chain too in case it stretched.

I'll call some indy shops around Charlotte, I would gladly pay $2500 to have it fixed at this point.

 

[Deplore]

Am I looking for oil that finds it way up from the sensors to the ECU? I did look at the two ECU connectors and sprayed them with electrical contact cleaner. If this is happening, how would I correct it? Also, I do have the oil pressure solenoid disconnected.

Replace the bad sensor/solenoid.

That's encouraging. I called Mercedes of South Charlotte about the tensioners and the service advisor quoted me $5k and said they always replace the chain too in case it stretched.

I'll call some indy shops around Charlotte, I would gladly pay $2500 to have it fixed at this point.

No wonder, you called the dealer. Their labor rate is $250/h at the very minimum, and the service advisor is padding the hours. Timing chain? That's only an issue in 300k+ cars with 15k+ OCI.

 

[pine1000]

Got it back together. Started immediately, but logged the P002164 very quickly when driving and starts running rough with a cylinder 6 misfire when the CEL comes on.

I'm going to turn it over to Eurowise in Charlotte as I don't have time to deal with this and my wife needs her car. They will do a diagnostic but quoted $2600 if it's the cam adjuster. On the phone they doubted that it is the adjuster, but I don't know what else it could be. If the tone wheel is also misaligned I would guess it will be an extra $1k.