CLK55 won't start - error code P0112

[alexanderfoti]

Thanks Wighty woukd have missed that.

Op I will pm you

 

[ajlsl600]

Strange issue with my CLK today. Headed off to work and car started fine, then 2 minutes up the road, I remembered that I'd forgotten something so headed back home. Pulled up outside and ran in the house to grab what I needed (was in the house all of 2 minutes) and then came back out, jumped in the car, and now I just get this noise of presumably the starter motor trying to start the engine, but doesn't actually crank.

I have an ELM327 WiFi OBDII gizmo and an app on my phone called "FourStroke" which pulls up the error codes on the car, and I'm getting a P0112 error code.

Feel like I'm going down the rabbit hole with this one as so far from looking on google, from what I can tell it could be the MAF sensor, the CPS, the fuel pump or an electrical fault! :-(

What's making me think that maybe it's not the CPS is that it doesn't start regardless of whether the engine is hot or cold, and I've read that normally if the CPS is faulty, it will normally work if you let it cool down for half an hour or so. It makes no difference and still won't start even after leaving the car for two hours.

What's making me think its' not the MAF sensor, is that most people say a MAF issue really affects vehicle performance, but won't stop the car from actually starting.

I guess it could be the fuel pump, but wouldn't that bring up a different fault code? I can clear the P0112 code with the app, then turn the key, hear the noise and the error code comes straight back again.

I checked the fuse in the boot for the fuel pump and that looks fine. I also swapped the relay for another identical one I borrowed from the fuse board under the bonnet (Hella 12v 4RA 002 542 26 19) that does another job, but that still didn't work so doubt it's that.

I uploaded a quick video of the noise (unfortunately the sound isn't great - Also please ignore the 3-4 "dunk" noises at the start of the video as that's an unrelated issue of a plastic cog hidden away behind the dash that controls air-con direction...apparently a common fault on the CLK's)

YouTube clip of car not starting

What do you guys think?

What I'm thinking I'll do is firstly change the CPS (this one)
and if that doesn't work, then change the MAF (this one)

and either of those don't work then possibly a new fuel pump?

Any help/advice would be much appreciated!

www.youtube.com/watch?v=oFtKAAPnXgQ check this is it relevant to yr drama..
i missed a bit of yrs , when my clk MAF failed it still started and seemed to run on a basic map seems you have .maybe more than one issue ,if you can get it on star as the 3 items you are thinking about wont be peanuts .sort of sounds like bad earth or shot starter, but difficult to be sure. good luck.

 

[jpowell79]

It looks like the car might be heading for the scrapyard

Huge thanks to Alex from AMF for all the advice given, and for taking the time to discuss the issues with the mechanic at the garage the car is currently sat at.

Any suggestions? Stick it on eBay for parts?

Anybody want to buy a CLK55 non-starter?

 

[alexanderfoti]

Just to update the thread, I have spoken with the garage that the car is at, and have gone through what they are seing, and it does look like the engine has jumped timing by about 8 degrees....

 

[LostKiwi]

I wouldn't think it would be that expensive or difficult to rectify that surely (as long as valves and pistons haven't been mating under the cylinder head)?

 

[alexanderfoti]

I wouldn't think it would be that expensive or difficult to rectify that surely (as long as valves and pistons haven't been mating under the cylinder head)?

Its more finding out why, timing case needs to be removed. I suspect broken guide on the tensioner side.

 

[LostKiwi]

Its more finding out why, timing case needs to be removed. I suspect broken guide on the tensioner side.

Again not a major job?

 

[alexanderfoti]

Again not a major job?

I believe the op has a large bill with the garage already and is keen to reduce the amount spent. We are unaware of any damage to valves etc as the heads are still on.

 

[ajlsl600]

sorry to read this its a real downer, the car needs an enthusiast with time and who does not need to incur labor costs then it could turn out ok

 

[jpowell79]

what I don't really understand is how the car can go from working perfectly fine, no issues at all. I drove for a few minutes, realized I'd forgotten something so turn the car back round, pull up outside my house, run in to grab something, come back out 30 seconds later, try to start the car, and now it stops working and the chain is all out of place? from that moment, the car hasn't moved. It was towed to the garage, and since then all that's really happened is a gearbox drop to change the CPS, and an ECU swap-out?

Is it a case that it's been slipping degree-by-degree over time and finally it's got to the point where the car just suddenly decides, "nope, enough is enough, I'm not starting for you!" ?

As I say, it wasn't like the car had issues prior to the fault, it was driving perfectly well

 

[alexanderfoti]

what I don't really understand is how the car can go from working perfectly fine, no issues at all. I drove for a few minutes, realized I'd forgotten something so turn the car back round, pull up outside my house, run in to grab something, come back out 30 seconds later, try to start the car, and now it stops working and the chain is all out of place? from that moment, the car hasn't moved. It was towed to the garage, and since then all that's really happened is a gearbox drop to change the CPS, and an ECU swap-out?

Is it a case that it's been slipping degree-by-degree over time and finally it's got to the point where the car just suddenly decides, "nope, enough is enough, I'm not starting for you!" ?

As I say, it wasn't like the car had issues prior to the fault, it was driving perfectly well

It will run OK but be down on power when the timing is off by 1/2 degrees. Any more and it will refuse to run as the ECU cannot get the correct sync between the cam/crank.

Chains tend to jump when started so its probably done it as you went to crank it.

 

[jpowell79]

It will run OK but be down on power when the timing is off by 1/2 degrees. Any more and it will refuse to run as the ECU cannot get the correct sync between the cam/crank.

Chains tend to jump when started so its probably done it as you went to crank it.

Hi Alex, yep it was fine just before I pulled up to the house, so I doubt it was even out by half a degree at the time. Perhaps at that moment the tensioner just so happened to give way?

Last year the tensioner on the aux belt just popped on me as I drove to work and I lost power steering and the belt sheared, etc, so could the same thing happen on the chain tensioner?

 

[LostKiwi]

Probably a different thing entirely. The chain guides on most modern cars are made from a low friction plastic. Over time and when subjected to oil and heat these have been known to crack or fracture. In your case I suspect the plastic guide has broken up hence the tensioner can no longer tension the chain. If there isn't enough tension on the chain then it can jump teeth on the sprockets (much like a slack bicycle chain can jump teeth).
Now if you're lucky a new guide and chain and all will be right. Irrespective as Alex said the front of the timing cover will need to come off to verify whats happened and change the damaged parts.

 

[LostKiwi]

sorry to read this its a real downer, the car needs an enthusiast with time and who does not need to incur labor costs then it could turn out ok

Hmmmm……

 

[ajlsl600]

hmmmm! NOT ME......

 

[alexanderfoti]

Probably a different thing entirely. The chain guides on most modern cars are made from a low friction plastic. Over time and when subjected to oil and heat these have been known to crack or fracture. In your case I suspect the plastic guide has broken up hence the tensioner can no longer tension the chain. If there isn't enough tension on the chain then it can jump teeth on the sprockets (much like a slack bicycle chain can jump teeth).
Now if you're lucky a new guide and chain and all will be right. Irrespective as Alex said the front of the timing cover will need to come off to verify whats happened and change the damaged parts.

I feel like that's exactly what has happened.

Hi Alex, yep it was fine just before I pulled up to the house, so I doubt it was even out by half a degree at the time. ?

Chain wear will give it probably 1 degree at 130K miles without it having jumped.

 

[jpowell79]

still undecided what to do.

Have been looking at a few new vehicle scrappage schemes and the deal on the mazda 3 looks pretty decent. £4k scrappage on the petrol and £6k on the diesel which is roughly the value of the Merc if it was working.

I've never really been one for buying brand new because of the depreciation, and the Mazda 3 isn't particularly exciting, but it's practical, economical, and the scrappage deal would almost cover the first years depreciation, so not too bad.

What I'm wondering though is if I should at least try to get the merc working by having the chain and guide done, and crossing my fingers that's all that the problem is.

What could I expect to pay to just get that done?

I guess what I'm thinking is that if it's only going to cost me £300-£400 to get those done to see if it fixes it, then it might be worth a gamble just to see if I can save it.

If on the other hand, we're talking 10+ hours labour to do the guide and chain, then it's probably not a risk worth taking, and I should just go with the scrappage offer.

It would be a shame to send it to the scrapyard....It wasn't a "mint" example AMG, but was a lovely car to drive, and always put a smile on my face when I floored it