[sorin1987]

My 2011 325i (N53B30 engine) has been experiencing engine misfires for a few months. I took it to my usual independent garage and they replaced Nox sensor, all spark plugs and coils but the engine still idles rough and sometimes at the first start the car will shake considerably and the Check Engine light will come on.
I cleaned the Vanos Solenoids myself and also I cleaned the MAF sensor also. No improvement.
A week ago the car just went into "limp" mode (got the big yellow engine light and the message: The engine operates on reduced power, you can still drive but bla bla bla). It didn't go away after a few restarts but the next day the car started fine and the message was gone from the dashboard but still was misfiring and shaking. I let it run for about 5 mins and then restarted it and it run smooth as nothing was wrong with it.
I bought an OBD2 scanner and I get the P0300-P0306 error codes (misfires on all cylinders) but also B2aaa which I couldn't find in the BMW error codes list but on a Mini forum I found that might mean bank 1 misfire. There was also another code P302c which means low fuel pressure.
I was expecting to see some MAF errors but there were none. What else can cause this behaviour. I was thinking it will be the MAF sensor and I could replace it myself but I am now taking the car to the BMW dealership and they will probably charge me an arm and a leg.
I was thinking faulty injectors also but I all the searches I did on forums about faulty injectors rendered misfires on only 1 or 2 cylinders where the injectors were bad. I find it unlikely that all 6 of them had gone bad at once.

The misfires are only happen at cold start and not every time. If the issue occurs and I let the car run for 3-4 mins and restart it it usually goes away but I still experience rough idle.

Any ideas what else might cause this? The car has almost 70k miles on it.
I am in the UK where the weather is never super cold, rarely goes below 0 Celsius in the winter.

[Pladi]

I know exactly what your issue could be. But i wont tell you because there has been alot of posts on misfires on this forum. And i am sure you can find the solution to your problem by searching a bit around. But of course we want everything nice and easy and fast.

Keep searching your answer is here.

[hazkirby]

Originally Posted by Pladi

I know exactly what your issue could be. But i wont tell you because there has been alot of posts on misfires on this forum. And i am sure you can find the solution to your problem by searching a bit around. But of course we want everything nice and easy and fast.

Keep searching your answer is here.

Can you at least supply the hyperlinks ?

[sorin1987]

Originally Posted by Pladi

I know exactly what your issue could be. But i wont tell you because there has been alot of posts on misfires on this forum. And i am sure you can find the solution to your problem by searching a bit around. But of course we want everything nice and easy and fast.

Keep searching your answer is here.

You mean what yours had? The battery?

These are some weird symptoms for a weak battery...

[Pladi]

Originally Posted by sorin1987

You mean what yours had? The battery?

These are some weird symptoms for a weak battery...

Those were my famous last words and my car runs like a swiss watch now a year later after replacing 1500 dollars of parts.

[Pladi]

Originally Posted by sorin1987

You mean what yours had? The battery?

These are some weird symptoms for a weak battery...

Most important thing when troubleshooting any issue is to be open minded.

You want to know how a a weak battery could be linked to your issue ?

The lambda sensor is used very quickly by the dme to stabilize idle. The battery heats up the lambda heater to get it up to operating temperature. So rough idle at start could be an issue with the power to lambda sensor to heat up the heater.

This is what i learned after looking at the DME logs with MHD SW. That was the tool i used.


See this link : https://datazap.me/u/pladi/log-bad-c...g=0&data=13-17

Look at the O2 DIP in voltage. After the voltage comes up idle stabilizes.

So i used REAL information to troubleshoot my cold start rough idle. I am saying what i am saying because of months of troubleshooting.

So you might consider the battery weird but thats because you dont understand how it works. These cars are very complex and weak batteries can cause all sorts of issue. There is alot of components that rely directly on battery power such as sensors and coils to name a few...

Your issue could be totally different... it could even be related to the valvetronic motor or worn cam lobes..

You need a good tool to troubleshoot these issues.

[sorin1987]

I just bought a Multimeter tool to test my battery power.
I am taking the car to the dealership next Monday anyway so I guess I'll find their opinion on what is wrong. I am sure that they will come up with some 1000's £ issue.

[GoRomeo]

Originally Posted by sorin1987

My 2011 325i (N53B30 engine) has been experiencing engine misfires for a few months. I took it to my usual independent garage and they replaced Nox sensor, all spark plugs and coils but the engine still idles rough and sometimes at the first start the car will shake considerably and the Check Engine light will come on.
I cleaned the Vanos Solenoids myself and also I cleaned the MAF sensor also. No improvement.
A week ago the car just went into "limp" mode (got the big yellow engine light and the message: The engine operates on reduced power, you can still drive but bla bla bla). It didn't go away after a few restarts but the next day the car started fine and the message was gone from the dashboard but still was misfiring and shaking. I let it run for about 5 mins and then restarted it and it run smooth as nothing was wrong with it.
I bought an OBD2 scanner and I get the P0300-P0306 error codes (misfires on all cylinders) but also B2aaa which I couldn't find in the BMW error codes list but on a Mini forum I found that might mean bank 1 misfire. There was also another code P302c which means low fuel pressure.
I was expecting to see some MAF errors but there were none. What else can cause this behaviour. I was thinking it will be the MAF sensor and I could replace it myself but I am now taking the car to the BMW dealership and they will probably charge me an arm and a leg.
I was thinking faulty injectors also but I all the searches I did on forums about faulty injectors rendered misfires on only 1 or 2 cylinders where the injectors were bad. I find it unlikely that all 6 of them had gone bad at once.

The misfires are only happen at cold start and not every time. If the issue occurs and I let the car run for 3-4 mins and restart it it usually goes away but I still experience rough idle.

Any ideas what else might cause this? The car has almost 70k miles on it.
I am in the UK where the weather is never super cold, rarely goes below 0 Celsius in the winter.

Sounds like a leaky or dirty injector to me, but before you spend any money on repairs, buy one of those injector cleaner bottles at you local auto store. Try it, its like $10.

[GoRomeo]

Originally Posted by sorin1987

I just bought a Multimeter tool to test my battery power.
I am taking the car to the dealership next Monday anyway so I guess I'll find their opinion on what is wrong. I am sure that they will come up with some 1000's £ issue.

You dont use a voltmeter to test a battery. Return it and buy a injector cleaner instead... Auto stores can do a "load test" on your battery, thats how you test a battery...FYI.

[sorin1987]

Originally Posted by GoRomeo

You dont use a voltmeter to test a battery. Return it and buy a injector cleaner instead... Auto stores can do a "load test" on your battery, thats how you test a battery...FYI.

As opposed to all the other forums and youtube videos out there suggest?

[david in germany]

Cough, cough, leaky injector, cough..

[sorin1987]

Originally Posted by david in germany

Cough, cough, leaky injector, cough..

Wouldn't a leaky injector result in misfires only on the cylinder where the faulty injector is? I find it hard to believe that all 6 of them went bad at the same time.

[david in germany]

Originally Posted by sorin1987

Wouldn't a leaky injector result in misfires only on the cylinder where the faulty injector is? I find it hard to believe that all 6 of them went bad at the same time.

Yes, only in the cylinder with the bad injector.

[Kaz_]

I have the exact same issues on n43 e90 320i 2010.

Misfire in morning switching on and off a few times and the eml flashing goes away and the car seems to drive fine for rest of the day no matter how many times I switch off or on again. The error codes I have is: cylinder 1 misfire 0029cd on maxicom

On obd reader I have
P13B6

P0301

The spark plugs were replaced earlier this year when car was serviced and following the above error message I have replaced all the ignition coils also which has made no difference. I have already spent 1k this year on the car with other issues previously all which have been resolved. Hoping this issue won't mean another costly expenditure which might mean it's time to buy another car. I enjoy the drive and had the car for 5 years but when ever an issue appears the BMW parts are so expensive in comparison to an Audi or VW parts.

[HitmaN1]

Kaz_ , you look at the problem in wrong way from the start.
First and first thing you should have done when the problem appears for one , two months, you should take out the injectors and be sure they are not leaking. Because of the position of the spark plugs and the injectors, if injectors are leaking, the fuel goes on the spark plug head (electrode) and when you have a cold start, the spark plugs can't make the spark corectly.
Another tip for keeping the coils 100% functionally is to change the spark plugs everytime at 30000 km OBLIGATORY!
If the spark plugs can't get the spark corectly, the coils have to suffer.

Another problem on N43 what can start the missfire is the NOX Sensor, which i recommend being replaced with NOXEM from bimmerprofs.