Diagnosing E46 All cylinder misfire.

[Arata 30]

Hi team. I’m just trying to solve the problem with my E46 320i M54B22 and the engine light came on. I’ve scanned the codes and there’s a bank 1 and 2 fuel bank trim and also all six cylinder misfiring. I’ve had my air intake boots replaced and all the vacuum lines are replaced as well, no leaking from valve cover as I’ve replaced one this week. O2 sensors are quite new as well. The car doesn’t stall or idle rough either. My guess is could be a CCV system failure which I’m going to replace them very shortly but I just want to ask for your opinion of what else causes to all cylinder misfiring? Please and thank you very much in advance.

[zero 1162]

There are far more knowledgeable people than me on this board, but vacuum leak would be first guess. The rubber plugs at the back of the manifold tend to tear or sometimes completely fall off. Have you done a smoke test?

[Arata 30]

Hi Zero. Not at this stage thinking of doing that. Some of my bmw friends are saying could be also the fuel filter pressure regulator as well?

[zero 1162]

Possibly - they do have a limited life.

I would be diagnosing it properly before throwing money and parts at it though.

[Arata 30]

Okay. Thanks heaps man!

[zero 1162]

If you are intending on keeping the car long term, then some preventative maintenance wont hurt.

The fuel filter is one of those such items. If you remove it, try blowing through it and see how blocked it is, and how dirty the fuel is that comes out.

[Arata 30]

Okay. Will have a look at that. Thanks man much appreciated.

[E30 325i Rag-Top 2956]

If you are replying the immediately previous post you don’t need to quote it. Just makes threads longer to read.

[Driftit 2078]

Have a search. There was another post with the same issues. Ended up being the ccv valve. 

I had these issues with my old E46. Ended up being a missing blanking cap on the back of the intake manifold. When I put a new one on I found it had been purposely removed to stop the ccv from functioning. (sh*t mechanics trick). Ccv was stuffed. Replaced that too and away I went. No more codes. 

Also the manifold can crack. The gasket between the manifold and throttle can perish.

[Arata 30]

Hi. So far I had the cylinder 1 to 6 all misfire codes for about 2 weeks and suddenly it disappeared on their own...

What I still have though is that fuel trim bank 1 and bank 2 too lean. 

Have replaced the fuel filter pressure regulator and have replaced the CCV. 

Fuel filter wasn't as bad as I expected, but had some dirt inside a bit so was worth replacing.

CCV was definitely worth as I did the one with my other e39, was expecting the bottom hose of the oil separator to the dipstick to be worn out, and was completely gone burger. 

Still has those 2 codes and with the yellow engine light on but no other codes so I'm guessing it's still having a vacuum leak somewhere... 

I'll try replace the gasket for intake manifold and throttle body. But after that I'm kind of running out of all options I can think of vacuum leaks...

Edited December 26, 2019 by Arata

[zero 1162]

Common vacuum leaks are disa valve gasket, intake elbows, rubber bungs at back of manifold.

Have you done a smoke test yet?

[Arata 30]

Disa valve gasket, both air intake lower and upper hoses are brand new. What do you mean by rubber bungs???

 

Maybe, maybe, those vacuum cap things at the rear of the intake manifold? 

 

I have a feeling that there are some missing but have not confirmed yet.

I have some new ones coming soon hopefully as I did see some from the e39 was worn out.

Could it be that?

Edited December 26, 2019 by Arata

[zero 1162]

If they are missing that is definitely it. If they are cracked or ripped that is likely it too.

 

If that doesnt sort it your next step is a smoke test

[zero 1162]

Numbers 15 and 17 here;

https://www.realoem.com/bmw/enUS/showparts?id=ET16-EUR-10-2002-E46-BMW-320i&diagId=11_2879

 

Also check secondary air pump hoses (if you have one), the dipstick tube oring, make sure the smaller of the two holes on the dipstick tube is not blocked, the 'F' connector on the intake boot, the throttle body gasket, the idle control valve gasket

 

 

[Arata 30]

Thank you very much. I'll have a look on those.

[allan 295]

Hi this may seem odd but have a look at the fuel tank filler cap seal and if the cap does seal properly. Also the sensor in the inlet manifold that deals with fuel vapours/ emissions to the carbon canister. As mentioned the two rubber caps/plug at the back of the inlet manifold.

[Arata 30]

Fuel filler cap does seal properly, although thinking about replacing soon but not urgently.

 

You mean the little evap thing at the front side of the intake manifold? I also have changed that recently to the new one. 
 

And yes those vacuum cap things at the back of the intake manifold I haven’t looked at it but pretty sure there is 2 different sized caps should be there but I think they are not there... just waiting to receive the shipment that I ordered and I’ll put the caps on where they should be and see what happens.