[basim07]

N53 330i

What to people make of my log

Developed a strange issue with running lean on bank 2, and under acceleration very bouncy acceleration under even moderate load with STFT bouncing all over the place. Gentle acceleration its ok but down on power.
Codes for Bank 2 lean, once had a code for Bank 2 Pre Cat O2 sensor not connected but never came back when cleared.

Bank 2 Pre Cat O2 sensor shot? Valve cover gasket has a small crack but the car isn't really affected at idle by it or gentle acceleration, and usually if they are affecting the car they affect it most at idle / low rpms and gets better on acceleration

Cylinder 4 had a new injector couple months ago due to misfires. Coded in correctly and adaptions reset. Coils were swapped prior to injectors and cyl 4 remained the issue so coil wasn't changed as they were only a year old. Sparks changed 2 years ago, however taken delivery of a new set of OEM plugs and also a new coil for cyl 4 in case thats the issue however I don't think that's the root of the problem here. Vanos solenoids replaced last year, I'm going to clean them up again and also fix the crack in the valve cover, just thinking do I need to replace the O2 sensor aswell while im there

The latter half of the log is where symptoms are most apparent, with acceleration up a hill

https://datazap.me/u/basim07/bouncy-...10-11-12-3-4-8

[0l0dom0l0]

Replace the valve cover + gasket.

Suspected CCV membrane faulty and the cracked valve cover won't help.

If you want to go further you can walnut blast, replace inlet manifold gaskets, new plugs and re learn adaptions.

Assuming you have a fully functioning NOX system with no faults?

[basim07]

Cheers for the reply mate!
Il tackle the valve cover then!
Out of interest, why would the cracked valve cover / failed CCv cause a lean condition on one bank only?

And yes nox sensor was replaced with an new OEM one last year when it packed!

[0l0dom0l0]

Originally Posted by basim07

Cheers for the reply mate!
Il tackle the valve cover then!
Out of interest, why would the cracked valve cover / failed CCv cause a lean condition on one bank only?

And yes nox sensor was replaced with an new OEM one last year when it packed!

I would guess it is to do with where the CCV pipe joins on the manifold.

From my research a faulty CCV causes a number of issues and the most common codes seem to be lean bank codes.

I would tackle that first and report back.

[0l0dom0l0]

You can check if its faulty by taking the top engine cover off and usually there is a whistle coming from the top of the engine at the back. If you put your finger on it there will be suction - there should be no suction at all.

Probably doesn't make much sense, but have a Google/ watch some YouTube videos and you'll see what I mean

[basim07]

There is a CCV fault, noted the whistle
Patched the valve cover leak
Blocked off the CCV vent as a temp measure until new parts arrive (can be done just increases oil consumption a bit)

Reset adaptions with INPA, couldn’t get bank 2 to set adaptations at all, bank 1 fine, STFT bouncing around wildly for bank 2 along with the lambda for bank 2 and persistent cylinder 4 misfire - now horrible even on come start misfiring immediately despite clearing codes.

Now Cyl 4 has had injector coil and sparks
Don’t think the MOSFETs bad as the injector is firing and I’ve never had the bank go together, but I’m gonna check it with A multimeter

Could this be intake valve gummed up? (I know valve cover needs replacing, however I can’t see any PCV pipes connecting to my PCV, it’s all integral to the valve cover?)

[0l0dom0l0]

A walnut blast is not a bad thing at all. Did mine when I changed the HPFP at 36k miles, about a year ago, and there was a suprising amount of junk on the valves. The N53 has EGR which means that cylinders 3 + 4 get extra caked up.

What index is your injector in cylinder 4? There's lots of talk about mixing index 11 with older variants, so if you have a new one in cylinder 4 and 5 and 6 are older then there's a chance that could cause you problems.

Assume the new injector is coded correctly?

Personally I think its worth taking your manifold off when you do the valve cover and checking everything is in order + replacing intake manifold gaskets.

What coils did you get also by the way?

[0l0dom0l0]

Also is the new injector actually new, genuine and from a reputable source?

A refurbished injector is a no go on these. They cannot be refurbished.

[0l0dom0l0]

Also update the DME to the latest software version if it hasn't been done already.

[basim07]

The new injector was from BMW, my Indy installed it, I’ve used him for a long time.
I need to check the index but it’s coded correctly, I double checked it and also recoded all of them after manually checking them to be extra sure
Coil is brand new OEM Bosch one
Sparks are oem NKG ones specific for this engine

The severity of the misfire now (basically cylinder 4 does not run properly at all even from a cold start) is unusual, in the past simple Misfires are intermittent and not as bad as this, plus the wildly fluctuating STFT on bank 2 positive to negative makes me think there is something significantly wrong rather than the usual coils or injectors
I swapped the new coil for a good one to double check and problems remains so isn’t the coil
The grounds look good
Ima double check the new spark plug tomorrow and swap cylinders
Aside from that plan this weekend is pop intake manifolds off and have a look, I suspect a severely caked valve may be the issue.
When I changed cylinder 4 spark plug it took a lot to get it out; was properly seized in and caked up black

[0l0dom0l0]

Might be worth doing a compression check to be sure also. Woukdnt usually recommend that but in your situation sounds like it would be good piece of mind.

STFT would be moving around if the cylinder was in total misfire, so it does suggest that you've got a more severe misfire.

Taking the manifold off is the right thing to do.
Its awkward as **** though! Good luck

[basim07]

Pulled my brand new spark plug out of cylinder 4 and it’s already covered in crap and black. Swapped in a good clean old one and it ran okay for about 5 minutes, thought the issue was fixed, but before long it started misfiring seriously again. Think the misfire is fouling the plugs real bad, and eventually they can barely function.

Too right it is! Been at it on and off since 11.30am!
Doesn’t help most guides online are for the N52 or N54!
Got it pretty much off except the EGR coolant hoses, one is round the back of the engine bay and I cannot get to it to get it off, any advice as to how to? I’ve given up for today gonna try again tomorrow.

My new injector Cyl 4 is index 11, the others are older index’s, so there’s another potential issue, but surely this mix wouldn’t cause a misfire to the point the car is undriveable?

[0l0dom0l0]

Yep, I had the same issue. Absolute nightmare trying to find any guides - there aren't any!

You need to remove the EGR body from the manifold - have you undone the 4 bolts that bolt the EGR body to the manifold? I searched for the TIS instructions and followed those but it was still really awkward.

I didn't have to remove the EGR coolant hoses. If you're talking about the metal EGR coupling which comes from round the back of the engine underneath the windscreen with 2 nuts then I think I just used a socket with a universal joint on it and just did it by feel. Pretty sure I dropped one of the nuts off it as well trying to put it back together and had to find another.

Take some pictures to jog my memory

[0l0dom0l0]

Re the index 11, its not ideal and there's a lot of mixed info on it - what index are the others?

It shouldn't cause a problem as bad as you are experiencing though.

Does seem strange how you're fouling the plug to the point of misfire.

[basim07]

Yeah I just thought that, instead of undoing the egr cooling hoses il just pop the EGR off the manifold before taking it out.

The old ones are sub index 10

If the intake valves aren’t terrible I wonder if the valve cover gasket has gone and possibly may be leaking oil into the cylinder, that’s another possibility, there was a bit of residual oil in the spark plug well from my valve cover crack, I’ve cleaned it up and will see if it returns now the crack has been patched. I may pull the injector too tomorrow and swap it to bank 1. I’m sure having them out for 2 minutes shouldn’t cause any issues with the seals if they go straight back in?

[0l0dom0l0]

Yeah that's the answer, you have to just hustle the manifold around to gain access to the bolts holding the EGR body on. Make sure you replace the intake manifold seals. The throttle body seal you can re use, mine was fine although new is always good.

I would advise against removing the injectors unless you have to, I wouldn't trust the seals to run again and they are minimal work to swap at a later date so keep it as a last resort.

From you position I would walnut blast the intake valves, replace the rocket cover + gasket, update the DME and re set adaptions then see where you are at.

I suspect you might be onto something with the oil consumption - a broken CCV and rocker cover won't be working in your favour.

[Cloverdale]

Bench testing o2 sensors is not difficult, requires a $10 multi meter and a flame source. See youtube for direction.

[basim07]

That’s true, but I’m not Convinced the O2 is at fault, cylinder 4 misfires even on a cold start before o2 sensors even start to get used!
Plus also had a cylinder 4 misfire with bank 2 o2 sensors unplugged

So cleaned cylinder 4 intake valves today. Manual clean with carb cleaner. 3 of the cylinders were quite clean whereas 3 had fair amounts of build up, interestingly cylinders 5&6 were fairly clean and 4 was worse of the lot! Still not as much as I expected, I think these have probably been cleaned in the past. EGR did have a lot of crud in it.

Absolutely b**** of a job, most definitely paying someone next time to do it. Once you know how getting the intake manifold off isn’t too bad I guess in hindsight. Putting it back however..... The silver EGR pipe bane of my life today. Also getting the EGR valve back into the manifold having have left it in situ prior. Not to mention forgetting which connector goes where 🤦*♂️
Intake manifold is on now just needs torquing tomorrow and then the rest all putting back together.

[Cloverdale]

I didn't walnut blast mine either when I cleaned-up before mods and it went well.

[basim07]

What would you say, the bad spark plugs covered in carbon or oil residue? Cylinder 6 is at the top then goes down in order. (you can see the threads have oil on them and cylinder 4 was baked into the threads took a lot to get it out.

[basim07]

Problem solved
Cars running better than ever

New injector to cylinder 4 was leaking even as new, the new plug on that cylinder was covered in fuel after being left overnight

Injector replaced and running much better, but still not right
Short term Fuel trims still really variable on bank 2 and lambda all over the place. Injector correction in response to this. No o2 sensor codes but I noted that bank 2 pre cat o2 sensor at times running at 350c rather than properly getting upto temp. No codes. Changed bank 2 pre cat o2 sensor and has never run better!

Leaking cylinder 4 injector and running rich likely shafted the o2 sensor, hadn’t failed completely but was all over the place.
Bit annoyed a new injector was leaking, was from ECP. Has gone back to their HQ to be passed back to VDO for testing before I get my money back.

[0l0dom0l0]

Good to hear you got to the bottom of it. Sounds like a combination of things. Interested to hear the response from them about the injector.