hi can anyone help please

Smartbear said:
could still be ccv valve-bunged up or split pipes....
regards
Click to expand...

Hi,
As smartbear says- running lean on banks 1&2 would defo point to an air leak after the MAF, chances of 2 coil packs or 2 O2 sensors going pear shaped at the same time are a bit slim!

Stu
 
So..update is i have had the inlet manifold off and replaced the seals and all the ccv pipes. Checked everything and put it all back together and its 100% the same. The fault codes are clear....pulling my hair out now.
 
Smartbear said:
could still be ccv valve-bunged up or split pipes....
regards
Click to expand...

Pretty sure this will be the answer, the oil cap trick is a known way of diagnosing the problem.

Does the engine use any oil at all? This would also point towards CCV.
 
I dont know about oil consumption as iv not drove it far at all. All the ccv pipes are new and have just been replaced by myself.
 
I did think that. I had a really good look when i had it off and on the bench but i couldn't see anything wrong with it tbh. Iv squirted carb cleaner all over while its running and nothing changes
 
Yes.

I highly doubt it will be the VANOS with the issue you are having.

The codes you have are lean on both banks. As previously pointed out, very unlikely to be both O2 sensors screwed so it probably is actually a lean running issue.

Have you checked for vacuum leaks? You need to check everything after the MAF is totally sealed.

It could be worth smoke testing the inlet system including the manifold.

Check the pipework from the CCV to the dipstick return and check the dipstick tube is OK, not blocked and sealed correctly to the block with an O ring. Check / replace the CCV. Check the DISA valve joint and unit itself for vacuum leaks.

If you are absolutely sure it is not a vacuum leak, then look to the fuel pressure.

You said the car has been standing for some time, the fuel system could be dirty, in particular the fuel filter. Is the fuel in the tank OK? Have you checked the fuel pressure? IIRC the pressure in the fuel rail should be between 3 and 4 bar. Do a leak test too to make sure it holds pressure after it is switched off and the pressure does not drop away quickly indicating a condition such as a duff / leaky injector
 
parky said:
When we did a fuel pressur pressure test it read 2.5 to 2.8 psi and was flickering (the gauge). Mmm
Click to expand...

I assume you mean bar?

If the pressure gauge is showing an accurate reading, this is not right.

IIRC fuel pressure should be very close to and stable at 3.5 bar. The system should also hold the pressure so it only loses 0.5 bar of pressure after 30 minutes of the system being switched off.

I would first try changing the fuel filter, then move on to looking at the pump which includes a regulator valve of some sort IIRC.

Once again, make sure you have good inlet hoses after AFM, including the idle control valve split hoses, etc. Manifold, CCV and hoses, cam cover gasket, oil dipstick tube, etc, etc. M54 lean codes are usually the result of vacuum leaks due to split old rubber pipework.
 
Hi. Yes i mean bar sorry...I will do another fuel pressure test and change the filter i think. There are no leaks on the smoke test and all pipe work which was ccv kit and new hoses including the throttle body hose have been replaced with new genuine parts. It must be fuel related
 
Theres no air leaks and all pipes and ccv valve etc are brand new.

It struggles (hesitant) up to 3000rpm. Once its passed that its revs freely. Sometimes it idles ok and others flutuates between 900 and 2k
 
You're original post said it was ok when the oil cap was off - is that still the same?

There's not a non return valve in the line by any chance?

Are the new pipes new or just look new?
 
The new pipes are brand new from bmw dealer. It was a full kit including the valve. Not sure about a return valve? Not that iv noticed? Where will that be or what would it look like?

When its cold and the revs are hunting up and down if you remove the oil cap the idle is much better. Once its warm though if you remove the cap then, then its worse.

the new plugs have again sooted up black so changed/cleaned them again. Could it be throttle body related?
 
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