BMW 2.0 petrol N46 engine missfire.

Hi Guys I’m so confused with this car and needed some advice on what my next step should be, I am still learning on the Scanner Danner course

BMW 3 Series
2.0 320i
LS05YRR
Engine code: N46 B20B
(E90/91/92/93) (05-14)
110 kW (150hp) 6200 rpm
R-Cat (2005-2008)

This car had a new clutch and starter motor fitted, after a few weeks it just died. Managed to get it started but is running rough at idle. When you slowly accelerate it seems to be ok and higher revs seems to not misfire. If I snap the throttle it hesitates and cuts out or misfires really bad until It gets to higher revs.

Fault codes were pointing to valve lift position motor inlet. (New one fitted and calibrated same problem) then I checked wave form from the wire (2 wires coming from ECU) should be 5V/01ms output signal at idle. I was getting 5V but then randomly spiking to 40v then 75v then 20v all over the place, so I decided to check the ECU and it was full of water.

Checked powers and grounds all good then decided to put a new ECU in, started the car and no difference. Only fault codes are miss fire detected codes.

All coils and spark plugs were changed previously by different mechanic.

At Idle car warmed up:

0.357 CO% vol
0.38 COc% vol
1.45 O2% vol
13.80 CO2% vol
105 HC ppm vol
Lambda 1.0

At Idle car warmed up:

Bank 1 STFT at idle is 25 then when I accelerate it goes to 0 then -10
Bank 1 LTFT 0

Bank 2 STFT 0
Bank 2 LTFT 0

At Idle car warmed up:

Bank 1S1 is reading -0.010mv
Nank 1S2 is reading 0mv

Bank 2S1 is reading 0.600mw
Bank 2S2 is reading 0.450mw



At full throttle

Bank 1S1 shoots to 2volts
Bank 1S2 still reads 0mv

Bank 2S1 is reading 0.800mw
Bank 2S2 (cannot remember what this reading was but was ok at the time)

I then checked the live data and noticed the MAF sensor signal was reading 0V all the time. I checked the pin data and ignition ON should be 1V and at idle should be 2-6V. Checked power and grounds they are all good, so I have ordered a new MAF sensor.

My question is can a MAF sensor cause all these misfires and O2 sensor reading for Bank 1 complete off? Or do I have a bad MAF sensor and a bad O2 sensor? Or am I going in the complete wrong direction with this?

Thanks for taking the time to read my post and any advices or help is much appreciated.

Harry

common issue with bmw engines with valvetronic. if you drive alot with not a lot of rpm fluctuation the valvetronic assembly gets stuck somewhat.

you said you calibrated it earlier. what tool did you use??

what fault codes do you get??

there is a test plan in the BMW ISTA that actuates the complete valvetronic system and test it for errors.

I used the snapon verus to calibrate it, it did say it was successful. You think I need to use a different kit to calibrate?

At the moment I’m only getting code: P1302 Misfire cylinder 2

the valvetronic can set misfire codes, and have rough engine running conditions at low rpm.

couple questions...

you said you replaced the DME because there was water in it, how did you code the new DME??

when you said you calibrated the Valvetronic system, did the test make you run the engine at idle, to were it ran the valvetronic to low position, and to high position 200 times?? that is the test that the factory BMW Ista system has you do. it takes about 20 mins to complete.

it goes from min. lift, to maximum lift, checking the motor itself, sensors, mechanical system, ect. and learns min and max positions.

The DME was not coded in, I got it from a company that sells ECU kits, KTS AUTOS LTD. They said it does not need programming, they sent me the ECU, Key sets and the Cas control module.

Also the test just said calibrate, didn’t ask me to start the engine and I don’t think it moved 200 times. It was done in like 2 minutes I did hear it move probably twice that is it.

hmmm, Im very suspicious of the DME they sent you. the CAS , ( car access system ) key and DME ( digital motor electronics ) are married and will start the car.

However the DME has no idea what car it is in. It most likely has the wrong vin it in, which means it does not know if the transmission is auto, or manual. what region its in, calibrations numbers, many things go into programming and coding modules.

can you read the VIN by global obd2??

also, what version do you have on your verus?? later versions have the ability to code.

Do you by any chance have a J2534 device??

The Verus is about 2 years old, havent updated it since then. Actually, now that you mentioned about the Vin when I fist installed it the snapon did say Vin not detected as one of the codes, but once I started it up it never came back?

I don’t have a J2534 device, do you recommend me buying one?

please go in global obd2 and see if you can read the vin and compare to what the car actually is.

please do this and I will advise next what to do

Ok thanks for your help will do this tomorrow at work at get back to you.

Hi got the details as follows:

Snap on picked up this info:

Vin: WBA……….403
2005 BMW 1 Series E87
2.0L Petrol N46B20B

Th Vin and car model is incorrect, engine is the same.

I would absolutely make sure the cars DME iss setup for your specific car. misfire detection can change depending if you have a flex plate, or a flywheel .

you can use BMW ista by there website here.
www.bmwtechinfo.com/#/login

you can get a day for $30. in the USA atleast.

and compare computer specs, and hardware and J2534 info here
www.bmwtechinfo.com/assets/system_requirements.pdf

or!!!!! you can do it another way.. I sent you a PM regarding that.

Hi Guys,
i have the same problem. However i have orignal ECU and vin number is correct.
Have You solved the problem?
Thanks a lot