2011 R56 JCW

I've been having a problem which I thought was related to my HPFP which was rebuilt about a year ago (near stalling on start). I sent the pump in because it was under rebuild warranty and I replaced it. The issue continued and I decided it could be a fuel supply problem and I changed out the fuel filter and in tank pump. The issue persisted and all of a sudden I got a P303 warning (Cylinder 3 misfire) - I did not have a warning to this point. I swapped coils and cylinder 3 was still bad. I pulled the plug and found that the center insulator had dropped so I thought that was the source. I installed a new plug and there's no change. I just pulled it and the plug is wet (dark). Is that because the cylinder isn't firing (maybe unspent fuel)?

The engine (short block) was replaced by a mini dealership 15,000 miles ago.

Any thoughts/suggestions on troubleshooting is appreciated.

 

You say that the spark plug insulator "dropped"? Where did it go? Did it drop into the cylinder? Did it damage the piston? Is the piston damaged? I think your next course of action is to perform a compression check, maybe followed by a endoscope to check the piston for damage.

 

In writing the reply, I looked up the parts of the spark plug - maybe insulator isn't the correct term. The "insulator material" that surrounds the central electrode fell and covered that part and stopped when it hit the ground electrode. It didn't fall into the cylinder.

 

Gotcha.

I still think your next step should be a compression check. These engines are notorious for chipping a valve.... If the compression check pans out, you might want to replace all 4 spark plugs and coils.

 

Copy will do. I'm headed out of town in a few hours, but will try to do this before I go.

 

My compression kit didnt have the small mini threads. Local rental kits didn’t either. I’ll hit this when I get home.

 

Fingers crossed that there isn't any damage - partner's n12 suffered a Bosch spark plug failure on cylinder 3, where the central electrode came out and scored the bore. Compression went from 200 psi to 175 psi, however with a new plug continued to operate. After a valve seat failure a few months later, had to rebuild the engine, now sorted but what a mess and cost!

 

Oh no!!! Well, there are the results

1: 170
2: 100
3: 0
4: 170

What's the next step? Should I check anything else or just start pulling it apart? Any recommendations on videos to get me through it?

 

Pull it apart. I have had a burnt away exhaust valve.

Some more people around had a similar issue.

Use the Bentley. Nothing too complicated, but will take a while. Make sure to keep the cam caps sorted. Make sure to take out ALL the check valves in the head before you bring it to the machine shop.

 

Based on the compression figures, you've got two poorly cylinders. Looks like 3 is either a hole in the piston or a valve seating issue; 2 could be a very badly scored bore. You will need to strip the engine down. You could start with a bore scope to take a closure look at 2 and 3 in terms of bore condition and poor oil down the exhaust and inlet ports of 3 with the piston at top dead centre. If the valves are sealing then the oil will stay in the ports, it the valves are not sealing the oil will bypass the valves and drop into the cylinder, this will tell you if its an exhaust or inlet valve issue. Other techniques include leak down test which will tell you where the gases are going and isn't invasive. But given the state of 3 it's time to take the head off and delve further.

 

Bad Bosch plug that screwed my partner's engine - IMHO the plug was fitted from new with a mechanical fault, after this little ****** screwed cylinder 3 went on to find further two plugs were mechanically faulty - 3 out of four plugs were faulty from new. Garage didn't want to accept responsibility - screwed them with some serious negative feedback in the public domain. Whole town now knows that hey fit doggy plugs! Added a picture of the faulty plug.


Dodgy Bosch plug - fitted by a 3rd party with a mechanical fault that went on to fail causing the centre electrode to drop into the cylinder - found two more plugs were also faulty - 3 out of four!

 

My scored bore - due to faulty Bosch plug dropping it's centre electrode into the cylinder.


Bore score due to faulty Bosch plug. Bore deglazed which shows up the groves! They are not supposed to be there!

 

Thank you all, any recommendations on the crank locking kit?

 

I would spend the little extra and get a quality timing kit:
https://www.ecstuning.com/b-schwaben.../023734sch01a/

 

Not sure for the timing kit. I mean it's just a few pieces of metal. I went cheap Chinese kits for all that stuff (timing, crank holder, injector removal). May need to file away a burr or corner here or there, but what gives.

The only thing I had to spend a bit but thought it was really useful was the engine holder bracket that you fasten to the alternator bolts.

 

Is this the holding tool?

 

Thanks for the guidance so far. I’m out of town for a week but I’ve started pulling it apart.

- what consumables do I need (gaskets)
- what should I do while it’s opened up (timing belt..)
- I see more oil than I think I should on the lower block, is this attributable to a valve, head gasket, or…

finally, I checked the dip stick and the oil is very low - to the top part of the downward pointing cone.

thanks!!

 

Yes. That holding tool mounts to the alternator bolts and I believe sits where normally the motor mount is. Otherwise you would need to have the engine jacked up all the time.

This gives you a lot of space. I liked it quite a bit.

 

Nothing exciting yet. I got the turbo pulled.

 

okay, I’ve pulled intake, exhaust and am at this point now. Do I need to pull what looks like a tensioner tensioner off the alternator. It looks like I have to. Do I need to do anything to release the pressure on the belt or just remove the two bolts?

 

You need to release the tension on the belt to remove it. I think I used a 27mm wrench or whatever that is on the tensioner.

 

I remember there is a small pin you can push after releasing the tension to fixate the tensioner.

 

One more follow up. Should I lock the crank and/or cams before pulling everything apart?

 

Nope, I recommend against locking.
The cams you need to take off anyways if you have the head off (if only for renewing valve seals).
The crank I wouldn't lock just to make sure you don't get tempted to use the locking pin instead of a crank holding tool to torque the crank bolt.

You will probably put a chain on, new guides and crank seal? I think you can remove the head with the chain still in (remove chain guide bolts, and have a helper hold the chain), but still: doesn't really matter. Finding TDC without the head in is somewhat trivial.

 

perfect. I ordered the crank holding tool and full timing chain replacement kit. Anything else I should order? I’ll need a head gasket - I forgot to order that.