[Sir_Dave]

So, need a bit of help diagnosing an issue with a car I recently purchased.

In effect, I did the usual, bought it on eBay, late at night, after a few glasses of wine. Naturally, I did this unseen, knowing full well that the car had a fairly obvious misfire and was using a bit of oil. Previous owner apparently couldn’t be bothered to fix it, so bought something else and plonked this on eBay. Being that N53’s are renown for their issues with coil packs, spark plugs & injectors, I took a punt on it. BMW had carried out a “quality enhancement” in 2011 and replaced all the injectors with Index 9, along with new coil packs & NGK spark plugs. Being that anything prior to Index 11 is generally useless, I simply assumed they had failed again. What’s the worst that could happen … well …

Cold start it starts instantly, runs ok for 5 seconds or so, then starts to jump about (really bad), with EML lights appearing & misfires on cylinders 5 & 6. After running for a couple of minutes, it struggles to start again, starter spins for quite a while.

Initial fault finding so far has resulted in:

Cyl 1: Unknown brand coil pack, NGK spark plug – smells of fuel.
Cyl 2: Delphi coil pack, NGK spark plug – smells of, & appears damp with fuel.
Cyl 3: Unknown brand coil pack, NGK spark plug – no fuel smell.
Cyl 4: Bosch coil pack, NGK spark plug – no fuel smell.
Cyl 5: Unknown brand coil pack, NGK spark plug – no fuel smell.
Cyl 6: Unknown brand coil pack, NGK spark plug – smell of fuel, very wet tip.

I cleaned all the plugs, re-inserted, then restarted the car, Cyl6 was instantly wet with fuel, all others were fine.
Then swopped the coil packs around, misfire stayed with Cyl5/6. Did the same with the spark plugs, misfire stayed on 5/6.
If I pull the oil cap, the idle stays the same, i.e. doesn’t get any/even worse.

Cylinders 6,5,4,3,2,1:

Untitled by Sir_Dave, on Flickr

Cyl6 Spark Plug:

Untitled by Sir_Dave, on Flickr

After buying a new 12mm adaptor, I then did a compression test (tested cold, all other plugs left in):

Cyl 1: Compression at 120
Cyl 2: Compression at 130.
Cyl 3: Compression at 130.
Cyl 4: Compression at 130.
Cyl 5: Compression at 110.
Cyl 6: Compression at 0.

At this point, after swearing a little, having read that a completely failed DI injection can occasionally cause compression pressure to bleed away giving a false reading, I bought a new Index 11 injector & de-coupler. Having removed the old one, I was faced this this, appears covered in white gunk?

Cyl6 Injector:
Untitled by Sir_Dave, on Flickr

New injector fitted and coded with INPA, re-started, still misfires. New compression test, this time done without any plugs in, all 155-165, barring cylinder 6 at 0.

Cylinder 5 sounded like this:

Cylinder 6 sounded like this:

When up to temperature, there is a decent amount of white smoke, this appears to have quite a nice smell to it. The previous owner said that since the misfire had started, it had started to burn a lot of oil

Now, ive had a head gasket go on an e46 M3 between cylinders 5&6 a few years back, but from memory, it wasn’t at zero (just 5/6 comps were lower than all the others) and being that that’s a closed deck block, there was no coolant usage etc as the break was between the cylinders. The last time I saw zero compression was on my R53 Mini I after a bit of a valve broke off and prior to that failing completely, it also smoked blue like a chimney on cold start. The 325i has no blue smoke, which in my mind, would be the normal indicator of valve and/or piston ring issues?

Just need a bit of advice really, I don’t really have the time, or inclination to take the head off myself, so am trying to self-diagnose prior to either sticking it back on eBay, or taking it to a specialist.

Thanks in advance.

[therealdb1]

Are you sure the wetness on plug 6 is all fuel and not water also?

The injector looks like it has been wet as it is corroded.

Might be worth pulling injector 5 just to see what that looks like but my guess is you either have a valve stuck on cylinder 6 or the head gasket has gone from cylinder 6 to the outside world.

When you turn it over for the compression check is it pressurising the coolant?

[Dormermike]

Can u put a camera into the bore for number 6 and have a look at the piston an general condition ? Probe type camera

[Chappers 71]

White smoke can be caused by a fuel system fault & a wet spark plug would most likely be caused by a leaking fuel injector.
Which seems to point to the injectors & looking at the state of the one you've pulled it looks like the injectors need replacing, also injectors should all be of the same index on each bank.
I would suggest that you have the codes read.

[Sir_Dave]

Originally Posted by therealdb1

Are you sure the wetness on plug 6 is all fuel and not water also?

The injector looks like it has been wet as it is corroded.

Might be worth pulling injector 5 just to see what that looks like but my guess is you either have a valve stuck on cylinder 6 or the head gasket has gone from cylinder 6 to the outside world.

When you turn it over for the compression check is it pressurising the coolant?

Yes, i suppose it could be water, at the initial point of checking i hadnt yet comp tested, so my initial assumption was that it would be fuel/oil as per reading plugs previously.

Re: injector 5, would i have to replace the black seal as per with a new/2nd hand injector, or is it likely to be ok if its coming out of, & going straight back in the the same place?

Unsure on coolant pressure, i've ordered a block tester so that will give me an issue of the state of the HG - will post up the results once completed.

Originally Posted by Dormermike

Can u put a camera into the bore for number 6 and have a look at the piston an general condition ? Probe type camera

Have ordered one, hopefully it'll arrive today

Originally Posted by Chappers 71

White smoke can be caused by a fuel system fault & a wet spark plug would most likely be caused by a leaking fuel injector.
Which seems to point to the injectors & looking at the state of the one you've pulled it looks like the injectors need replacing, also injectors should all be of the same index on each bank.
I would suggest that you have the codes read.

Re: the white smoke, having watched a billion N54 videos (they have the same type of injector), this was my initial hope, hence the purchase of a new Index 11. Normally, in this situation, i would replace all the injectors/coils/sparks as a matter of course, but with the injectors being so expensive, for the purposes of fault finding (the lack of compression) on CYL6 i have bought just the one. If/when the compression issue is resolved i would naturally replace all of them with Index 11.

Re: the Codes, ive got Carly & INPA. Not using the 2.023 loader for the MSD80 as per the Bimmerprofs websites suggestion however (no idea how to update it), so just on 1.001 for the time being.

Carly/INPA are giiving me 29D1 & 29D2 for CYL 5 & 6 misfires, along with 29F3 for low pressure fuel sensor failure (the live data is also showing its stuck at 6500 hPa instead of 5k so assume its toast). Finally there is the (fairly standard on the N53) 29FE Nitric Oxide Catalyst aging.

Video of cold start. As you can see, the idle is generally ok initially, albeit rather tappy/loud, after which it starts to struggle massively:

[Dormermike]

Btw I've just discovered that if you have a camera probe small enough you can reach cylinder 6 valves via the inlet manifold MAP sensor hole. Only two torx screws and you're in. I just checked my inlet valves for carbon and they are pretty clean for 60k miles. Just saying in case it helps you as a possible entry to back of that cylinder.

Sounds like your engine has a few issues. I'd be solving cylinder 6 zero psi before putting any more money in it (which presumably that's what you're doing).

Edit to add image hope nobody minds:

[Chappers 71]

I hope you get it sorted, it's unfortunate that injectors are so bloody expensive & seem to have so many issues, fortunately for me mine are still the original injectors & have now covered over 112k & are still good

[Sir_Dave]

Quick update on this.

Had a leakdown test done today at BMS Surrey and the inlet valve on Cyl6 is stuck open slightly. Realistically, its quite difficult to tell whether the cause is bending/sticking as you can only see so much with a borescope, but he said that the top of the piston & cylinder walls seem to look ok. To speed up getting it back on the road, i've just bought a used cylinder head complete with cams/valves etc, so the idea is to simply swop them over, then strip the old head & sell the unused parts.

Currently trying to decide whether i can bothered to do it all myself, on the drive, in the cold & wet, or just pay them 12 hours labour to do it ...

[therealdb1]

I thought it would be something like that.
If you want the car running asap and you have nowhere warm and dry to work on it I would pay the money and get the garage to do it.
Trying to change a head outside in the snow is not a guarantee for longevity of the repair and the garage will probably offer a warrantee on their work so that you know it will be running right when you get the car back.

[Sir_Dave]

Bit of an update on this.

In the end, whilst the garage had quoted a very reasonable £1200 in labour/parts, that, plus the cost of the 2nd hand head at £500, seemed rather a lot to stomach. Being that i like a bit of a challenge/something to tinker with, i thought, "if its broken already, i cant make it anymore broken" and decided to have a go at doing it myself.

Weekend of the 30th/31st April, i made a start to the 325i's strip down ...

Starting point

Untitled by Sir_Dave, on Flickr

Inlet manifold removed

Untitled by Sir_Dave, on Flickr

Valve cover removed

Untitled by Sir_Dave, on Flickr

Organised chaos

Untitled by Sir_Dave, on Flickr

Well hello there broken valve spring:

Untitled by Sir_Dave, on Flickr

Turned the car over by hand a few times and by peering through the inlet opening, it appeared that the valve was still moving within its guide, but only to a certain point - meaning that the valve was still open say 5mm or so. Upon looking at the valve spring with the valve cover off, it appeared that i had a broken spring; naturally this would stop the valve closing all way as its not being pulled all the way back out of the cylinder head. Its VERY difficult to see as its rather close to the bulkhead, but i decided to order the N53 timing tools and have a proper look before even considering pulling the head off.

----------------

Then 2 weeks ago.

Valve cover back off, timing tool fitted:


Untitled by Sir_Dave, on Flickr

Timing chain tensioner removed, vanos hubs removed from cams, top half over inlet cam cover removed:

Untitled by Sir_Dave, on Flickr

Both cams & their ledges removed:

Untitled by Sir_Dave, on Flickr


Untitled by Sir_Dave, on Flickr

Hydraulic lifter removed & valve spring on cyl6 inlet side is confirmed as the issue:

Untitled by Sir_Dave, on Flickr

At this point, i realised that my recently purchased ebay cheapo overhead valve spring compressor wouldnt fit. FFS.

---------------

Then last weekend.

Testing my new Laser overhead spring compressor tool on the spare cylinder head i bought for "practice":

Untitled by Sir_Dave, on Flickr

Then doing it on the cylinder head proper:

Untitled by Sir_Dave, on Flickr

In order to stop the valve dropping down into the cylinder, i held it very lightly with some padded plyers held together with masking tape. Whilst the compressor tool is fine for one-handed use, removing the valve spring keepers was definately a job that required two hands!!

One very broken valve spring:

Untitled by Sir_Dave, on Flickr

All replaced and now i have a valve that seats correctly:

Untitled by Sir_Dave, on Flickr

New rocker cover gasket & rocker cover back on again:

Untitled by Sir_Dave, on Flickr

Nearly there:

Untitled by Sir_Dave, on Flickr

Then time to get the jump leads out, crack upon a beer to calm my nerves and start it...

Success!!

Being that there isnt much info out there for the N53, i used the following N54 guide for the tear down, barring the turbos, it would seem they are very similar in terms of process: https://www.e90post.com/forums/showthread.php?t=1080990 along with the TIS N53 repair manuals: https://www.newtis.info/tisv2/a/en/e...als/11-engine/

The N53 specific tools purchased were as follows:

12mm spark plug socket
Gunson 12mm adapter kit
Laser 5153 Chain Tensioner Tool
N53 Timing Tool
Laser 5258 Valve Spring Compressor

I also needed to purchase a Teng 3892ag 5-25nm 3/8" Torque Wrench for lower torque nuts/bolts as my Halfords one only went down to 30nm.

Repair parts:

Low Pressure Fuel Sensor (13537614317)
Elring Rocker Cover Gasket (11127544368)
N53 Valve Spring (11347563459)
2 x N53 Camshaft Bolts (11367524954)

All in all, very happy!!

[Phil325i]

Great job Sir! A couple of questions:

1) How many miles on your engine?
2) Was there much carbon on the backs of the inlet valves?
3) When you removed the cams, did you check for wear on the bearing ledges from the 'rectangrings'?

See this vid at point 10:35 on:

[Sir_Dave]

Originally Posted by Phil325i

Great job Sir! A couple of questions:

1) How many miles on your engine?
2) Was there much carbon on the backs of the inlet valves?
3) When you removed the cams, did you check for wear on the bearing ledges from the 'rectangrings'?

Thanks

1. 105k miles on the engine, full service history with oil change every 12k on average. Last service doen 7k miles ago.
2. Not on 6 as i guess for once, the fuel was cleaning it out nicely (being that it wasnt closing lol), but the other 5 were a bit gunked up, not so bad that i thought "OMG i must clean this" though. If i keep it and put on a 3 stage manifold i will give them a once over with the toothbrush however.
3. Cam bearing ledges looked fine tbh, no scoring/striations to worry about. Similar situation with the spare cylinder head i bought as it happens (no idea on how many miles on that though unfortunately). Also, unlike the N52 in the video, both the exhaust & inlet are removeable (as per the N54), so its not a head off job if there is an issue in future. With the correct tools, now ive done it once, its a fairly easy job to get to the "cams out" stage on this engine.

Hope that helps

[therealdb1]

Crazy man tackling a job like that outside in a car park

Well done for fixing the problem and documenting what you did!