Camshaft lobe shattered... and faulty ECU!!

[richcoopS]

Hi all

Have a problem with my 52 plate MCS (54k on the clock). Last week it started coughing as I was driving along, then it lost power and the car started stalling, managed to stumble home...

I plugged in my OBD code reader that weekend, which told me: "Cylinder 1 Misfire Detected".

At this point I thought it could be plugs, leads, or the coil. Well I've swapped around the plugs, problem was still there (in cylinder 1). This evening I replaced both the ignition coil and HT leads and the problem is still there...

I'm going to try and check the injectors this weekend, but has anyone had a similar problem? I searched and there are very few threads on the forums.

Any advice/suggestions would be much appreciated. It will have been off the road two weeks now

Many thanks

Rich

P.S. car was running fine before this - although fuel consumption was up last two tanks, I just thought it was because I'd fitted a Miltek cat-back and my right foot was heavy!

[C.Noble]

P0301 (I assume this was the code???) is one of the easier ones to find, though the result could be expensive!!!

If you have already removed the possibility of it being the ignition system at fault, which means you are certain it is not plugs, leads or the coil. Then I recommend you carry out a compression check and then injector check (swap over no1 and no2 injectors and see if the fault codes changes to P0302).

Does the engine run on 3 cylinders from start up or only after the light comes on?

[richcoopS]

Thanks for the quick response! Yes P0301 is the code...

Yep - I've removed the ignition system from the picture, now to look at injectors. That's this coming weekend's job - as I'm in work all week and when I get home its too dark to work on the car.

I cleared down the fault and then started up again - engine sounds like its only running on 3 cylinders from the off. Then the engine fault light comes on again.

Failing a problem with the injector in cylinder 1 (which shouldn't be too hard to replace) what could the problem be? At the mo, I've tried to solve this myself - but may have to try and do a compression check - just difficult to get hold of these tools and the car is in no state to drive anywhere!

Thanks for your help

[Richard Crofts]

If you still can't find it and are totally stuck, then try popping it on the RAC/AA up to Thinkmini near Worcester to see if they can help out. They have full diagnostics kit and also facy doodahs to look inside the head/pistons...they can also run compression tests etc. They can also help see AF readings and all sorts of fueling stuff etc. Be cheaper than getting BMW, and they know thier stuff as daves a whizz at electrics on cars and adrian is a former BMW tech.

Sorry i can't help directly, but if your stumped it may be worth speaking to them.

[Laxsion]

Exactly the same problem what my S had before , the reason should be fuel issue. Try to fill up with higher grade / good reputation brand of fuel for 1-2 tanks to see if this can help or not before your put lots of money & time to replace some unnecessary parts.

Good luck

[richcoopS]

Hey guys, thanks for your replies, much appreciated.

Laxsion - were you getting a misfire reading for a specific cylinder? I would have thought that if it was the fuel, then I would get misfire's in other cylinders too? I was about a 1/4 of the way through this tank of fuel when it happened too (from Morrisons)! How did your fault register?

My Dad is coming to visit this weekend bringing with him a cylinder compression test tool and all his meters - so hopefully we'll be able to find out whether the problem is with an injector or with the head, or it is electrical.

Will keep you posted...

[richcoopS]

Oh dear...

So a cylinder compression test confirmed my worse fears; no pressure in cylinder 1, so looks like the value is stuck open - could be a broken valve spring. At least the other 3 cylinders read exactly 12 bar each and seem fine.

Looks like I'll be spending the next few weekend taking off the cylinder head and having a look round to see what's gone wrong. Can't believe it, this is a car that has only done 54,000 miles.

At least it'll give me a chance to make some mods. Still gutted it's off the road

[richcoopS]

Took the valve cover off today - no probs with springs, collets etc. Shone a torch down the sparkplug chamber, and looks like there is a hole in the piston...

Taking the cylinder head off tomorrow, to see how bad the damage is and what has caused this.

[Lucky Dave]

What was the spark plug like?

What mods have you?

[richcoopS]

Haven't got any engine/power mods (bar Miltek exhuast), or none that I'm aware of anyhow!

Cylinder 1 Spark plug was black when I first took it out. Took out 4 and it wasn't as bad the first time. Now all 4 are pretty bad, but that could be down to the amount of time I've cranked the engine while its been siting.

[Lucky Dave]

We have a small camera which can be passed into the bore to have a look about, it may be worth borrowing one of these.

The fact the plug is intact is good news, well sort of!

[richcoopS]

Yeh, i suppose... , I have to laugh or I'm going to cry!

Taking the cylinder head off today and dropping the sump, so should have some more news!

thanks for the interest Lucky Dave

[Richard Crofts]

I think that means its time for an RMW stroker with nice shiney new pistons

Sorry to here mate, good luck with the rebuild

[richcoopS]

Haha! I think that may be a good idea!!

Started work this weekend. I've stripped everything back, intercooler off, fuel rail and injectors off, valve cover is off, air intake and DME out, bumper, wheel arch and pipes off. Connectors and Sensors all off. Intake manifold is off, exhaust manifold is off. Drained engine oil and coolant. That and more (forget what else I've done) took around 12 hours this weekend. Nightmare problems with some rusted bolts but managed to get them all off in the end.

All that needs to be done now, to find out what caused the piston problem, is drop the engine down, remove the engine mount and then take the cylinder head off... hopefully there is no more damage than piston, valve or something like that.

But as I can't get home till Christmas I'm hoping my Dad will sort out taking the head off - as I'll need to order replacement parts next week to arrive in time before Christmas. It's going to be a hard Christmas replacing parts and reassembling, but It'll be worth it and every job I do after this will seem easy!

Will keep you all posted on developments!

[richcoopS]

My dad made some progress last night, taking off the engine mount and temp sensor off. He managed to loosen the camshaft sprocket bolt, so next step is to remove the camshaft timing chain and then remove the head.

He thinks that the piston may not have a hole in but a large dent... which would suggest bent valves. Although not sure what has caused that because I have not over revved on downshifts, and when hitting the limiter the ECU shuts down the cylinder to prevent this kind of thing happening. This all happened doing a steady 60mph in 6th!?

Hopefully this means that the damage may not be as bad as first thought, and will be cheaper to replace parts... but we'll see! Oh and at least we won't have to drop the sump.

Next update to come later this week!