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Mini R56 1.4 N12B14A 2008 - Rich Lambda and fuel trim not correcting - Fixed #

Posted by Martin Kelly on April 3, 2017, 11:49 am

Year of Manufacture *: 2008
Engine Size and Code *: 1.4 N12B14A
( Optional ) Scanner Used: Verus
( Optional) Fault Codes: 287D - Vanos inlet actuator movement

Hi, this originally had Vanos code not operating inlet correctly, removed both VVT solenoids, cleaned oil gauzes, flushed, removed and cleaned gauzes again, now clean, fresh oil and filter, all working ok now and DTC did not return.

Lambda reading still around 0.94 to 0.96 at fast idle, 0.98 at idle - MOT emission reading.
Using Verus BMW Mini system the Lambda shows 0.98-0.99 but on EOBD it matches the gas emission reading of 0.94-0.96 and the STFT is between +2% to -3%, this does not make sense, I would expect to see say -20% surely?

Scoped the crank and both cam sensors to check for chain wear, all ok.
Have disconnected EVAP and plugged, no change.
Fuel pressure tested ok.
Have replaced front O2 sensor, was un-marked brand, for Bosch,and new plugs fitted, no change.

The car runs very smooth and drives fine.

If anyone has any ideas on this please I would be most grateful.

Thanks, Martin.

Re: Mini R56 - Rich Lambda and fuel trim not correcting

Posted by aidan birley on April 3, 2017, 1:32 pm, in reply to "Mini R56 - Rich Lambda and fuel trim not correcting"
Aidan Birley

hi Martin

Has this had a good run since sorting vanos fault?

Air leak up stream of lambda sensor could be a possible cause.

aidan

Re: Mini R56 - Rich Lambda and fuel trim not correcting

Posted by Martin Kelly on April 3, 2017, 1:43 pm, in reply to "Re: Mini R56 - Rich Lambda and fuel trim not correcting"

Hi Aidan, have smoke tested intake and exhaust, all ok.
I will be taking it on a 25 mile run home this evening and back 25 miles tomorrow morning, does it need time to adjust?

Thanks, Martin.

Re: Mini R56 - Rich Lambda and fuel trim not correcting

Posted by aidan birley on April 3, 2017, 1:53 pm, in reply to "Re: Mini R56 - Rich Lambda and fuel trim not correcting"
Aidan Birley

Hi Martin

>>>does it need time to adjust? <<<<<

I am not that familiar with these but I would expect the vanos code & subsequent reset to have an effect on Fueling / trims / data.

So would be sensible to complete a couple of drive cycles before jumping to conclusions.

may be worth checking oil filler cap is sealing correctly to.

Regards Aidan

Re: Mini R56 - Rich Lambda and fuel trim not correcting

Posted by andrew young on April 3, 2017, 3:00 pm, in reply to "Mini R56 - Rich Lambda and fuel trim not correcting"
Andrew Young

You could be chasing your a**** here.I have found these engines only perform correctly with genuine Mini lambda sensors.

Re: Mini R56 - Rich Lambda and fuel trim not correcting

Posted by Ed Kaps on April 4, 2017, 12:18 pm, in reply to "Re: Mini R56 - Rich Lambda and fuel trim not correcting"
Edward Kaps

I agree with Andrew
I am sure there was a discussion some time ago about using NGK lambda sensors to correct this type of problem. Your live data is correct-showing slightly rich, gas test of lambda is correct--showing slightly rich, your live data is a computed figure-not Lambda.

Re: Mini R56 - Rich Lambda and fuel trim not correcting

Posted by Peter Warman on April 4, 2017, 1:22 pm, in reply to "Re: Mini R56 - Rich Lambda and fuel trim not correcting"
Peter Warman

This may be the thread

http://members5.boardhost.com/ukautotalk4/msg/1381737032.html

Genuine sensor fixed this one

Re: Mini R56 - Rich Lambda and fuel trim not correcting

Posted by Martin Kelly on April 5, 2017, 5:54 pm, in reply to "Re: Mini R56 - Rich Lambda and fuel trim not correcting"

I have driven the car 2 times 25 mile runs now, runs well and no faults logged but still slightly rich.
I know these have a low intake vacuum, does anyone have a figure at idle so I can check the MAP sensor value.
Regarding the Bosch O2 sensor; it has Bosch Motronic system fitted, would that not work correctly or is genuine BMW Mini still preferred?

Thanks for info, Martin.

Re: Mini R56 - Rich Lambda and fuel trim not correcting

Posted by Martin Kelly on April 13, 2017, 8:10 am, in reply to "Re: Mini R56 - Rich Lambda and fuel trim not correcting"

We have an identical Mini in for other work (emissions checked and all good) and was able to swap front O2 sensor and no change to our faulty car.
The Bosch one supplied to us, on closer inspection, has the Mini part no. on it as well as Bosch no., as did the one from the donor car.
We have also found that when trying to view live data group 'Valvegear' data comes up as no comms whereas it did communicate when we first looked at the car.
The good Mini does communicate with 'valvegear'so Verus is ok.

Swapped over Valvetronic position sensor as well, no change in comms or emissions.

Martin.

Re: Mini R56 1.4 N12B14A 2008 - Rich Lambda and fuel trim not correcting #

Posted by Richard Endean on April 13, 2017, 6:46 pm, in reply to "Mini R56 1.4 N12B14A 2008 - Rich Lambda and fuel trim not correcting #"
Richard Endean

I've racked my brains trying to remember the job but we did have one of these where the cat substrate had dropped in its casing - completely shrouding the downstream sensor. All sorts of weird fuel trim errors. Just take out the sensor and shine a torch in the hole - 10 minute job.

Re: Mini R56 1.4 N12B14A 2008 - Rich Lambda and fuel trim not correcting #

Posted by Glyn Morgan on April 14, 2017, 4:40 pm, in reply to "Re: Mini R56 1.4 N12B14A 2008 - Rich Lambda and fuel trim not correcting #"
Glyn Morgan

Hi Martin,

Can you reset adaptions/learnt values ?

Is your post cat O2 sensor working correctly and what voltage is it showing driving under cruise conditions?

Regards

Glyn

Re: Mini R56 1.4 N12B14A 2008 - Rich Lambda and fuel trim not correcting #

Posted by Martin Kelly on April 18, 2017, 12:04 pm, in reply to "Re: Mini R56 1.4 N12B14A 2008 - Rich Lambda and fuel trim not correcting #"

Just removed rear O2 sensor to check for cat debris, all clear.
Will check rear O2 data later, don't think Verus can do Adaptations but will check.

Martin

Fixed #

Posted by Martin Kelly on May 5, 2017, 1:48 pm, in reply to "Re: Mini R56 1.4 N12B14A 2008 - Rich Lambda and fuel trim not correcting #"
Edited by board administrator June 16, 2017, 1:58 pm

Even though I scoped the crank and cam sensors and checked it against the trace in 'waveform' forum I thought the timing was ok.

I decided to remove the cam cover and actually check the cam timing using the cam and crank locking tools and found that the inlet cam was out of alignment by only a few degrees.
I also noticed that a new chain tensioner had been fitted, maybe the stretched chain had pulled the inlet cam out of alignment?
Carried out cam timing adjustment and the emissions are now good, Lambda 0.997 at fast idle etc.
We will be recommending a timing chain replacement in the future.

Thanks for all your comments, much appreciated.

Martin.

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