so a week or so before i had by pcv replaced was getting the engine light coming and going. i didn't bother checking the codes as i knew it would likely be the pcv.

However the oil breather system is all good now and the light persists. I initially blamed lag so thought id clear the faults and run on petrol for a bit but alas the fault is back...

The codes i get are: multiple fuel trim 2 :limit reached and additive fuel trim 1: limit reached...

Where do i start? would clearing the adaptations sort this? can this be done easily?

Thanks Current stable:
2006 BMW M6
2007 4.2 V8 S/C FF
Gone:
2002 4.4 V8 FF

after a clear and drive again I'm now getting additive fuel 2 : limit reached??? argh

also just realised I dint mention above I have a fault o2 sensor - o2 sensor 1 after cat that is ever present, however ts my understanding this is just belt and braces everything is running right so shouldn't be my problem? Current stable:
2006 BMW M6
2007 4.2 V8 S/C FF
Gone:
2002 4.4 V8 FF

right did a bit of further research at lunchtime,

firstly, I did the key to position 2 while foot on pedal for 30 second adaptations reset trick.
secondly, I disconnected the batter for 20 mins, then touched the two terminals together, then after another 20 mins connected it back up.
thirdly,I had a spare universal o2 rear sensor as you may have seen on my other post. I thought id change it to fix that fault... rather optimistically I disconnected the plug first... then tried to unbolt it smack 7 bells out of it, it wouldn't move and I had work to do so I just plugged the cable back in for now... but hold on.. I plug the scanner it and its all working now ... strange...

anyway after starting up idle was high around 950rpm, and stayed like that hunting a little bit. I then plugged my scanner in and went for a drive and recorded a couple of videos of the fuel trims and o2 sensor voltages... if anyone who roughly knows what it should look like could take a quick look id be appreciative.

Fuel Trim


O2 Sensor



many thanks Current stable:
2006 BMW M6
2007 4.2 V8 S/C FF
Gone:
2002 4.4 V8 FF

Ok been for a 90 mile drive this morning - 70 miles in on the road engine light on... i’d Only been cruising as well nothing erratic. Only had my little reader but the fault codes amount to the same p1171 and p1174. Any ideas where to even start I am at a loss now? I had a new Bosch maf 18months ago so hoping that’s ok... Current stable:
2006 BMW M6
2007 4.2 V8 S/C FF
Gone:
2002 4.4 V8 FF

clear the codes , run on petrol only , if you have an immediate pending 1171/4 code you are most likely pulling in air or your maf is goosed.

if it doesn't bring any lean codes when on petrol and only does so when on lpg you need your system looking at , most likely sticky injectors or needs a tune up[/u]

Hi dingg

I haven’t ran on lpg since Sunday petrol all week and the codes can take like this morning 70 miles before they throw up so quite sporadic - any ideas on that as there seems no pattern? Current stable:
2006 BMW M6
2007 4.2 V8 S/C FF
Gone:
2002 4.4 V8 FF

there is a pattern , they'll throw up on the 3rd engine run

use a simple elm327 to show the codes and an app such as obd doctor or piston on your phone , these will show pending codes

IF as you say its showing lean running on petrol , you most likely are pulling in unmetered air , onfirm with code readr that your o2 sensors are reading okay as well but it would be unusual to have one on each side fail at same time.

my money is on air getting in , simplest , most common and cheap to sort

Ok - not had eml for ages now but still shakey on startup. Disconnected the maf doesn’t run much different.
more drama this morning seems to be getting worse - maf still disconnected -

Started it from cold stalled straight away.
Started again kept revs on and out into drive with foot down and the revs would not climb?? Then tried reverse and it crawled back ok then out into drive and it slowly sprung into life, all the while shaking like it had dropped a bank! No eml though! Any ideas? What the chance of a bank 1 cam sensor or a crank sensor? Current stable:
2006 BMW M6
2007 4.2 V8 S/C FF
Gone:
2002 4.4 V8 FF

Right this got real bad now... driving back home started her up died about 4 times until I held throttle. It then started backfiring massively from somewhere under the car so loud everyone was looking at me. Turned it off and filmed this video backfire is quite quiet on the video. Faults are now not mixture related but maybe as maf was disconnected, I have cylinder 1/2 misfire and severel cylinder misfire codes.



Argh..

Again once you get going and it sorts itself out it’s fine? Current stable:
2006 BMW M6
2007 4.2 V8 S/C FF
Gone:
2002 4.4 V8 FF

THe engine does rely heavily on the MAF sensor so get one plugged in (generally only genuine ones work).

Fuel trims seem to only adapt under moderate acceleration. I went through similar in a different car and noticed that after a reset and drive, the trims only adapted during a moderate pull away. V8 or else ...

theres no point running the engine with the MAF disconnected otherwise how does the ecu know how to set the feuling ?
Induction side sensors control apprx 75% of fuelling O2's do the fuel trim basically fine tuning it. once they cant alter the(25%) trim enough = EML and codes take a good look at feul trims live and look for differences between the two banks. And if you can voltages if any over 1v O2 knackered plenty on youtube for testing four wire o2's also on four wires if the heater circuit goes it can tell you a banks running lean when actually its the oppsite and its running rich.
hope it helps  Range rover 4.2 SC 06MY.

Have you physically isolated the LPG?
I once spent a lot of time trying to find a similar fault on a Jeep and had assumed that because it was running badly on petrol then the LPG wasn't to blame, however it turned out that there was a failed seal in one of the LPG injectors which was allowing gas to pass which was causing all kinds of mixture/trim problems when running on petrol.
There's also loads of possible inlet air leaks possible around the LPG system?

Hi all maf back in it’s not popping now but it’s stalling still and running like a dog on startup in one in ten starts from warm. The rest of the time she’s fine. Only faults are fuel trim additive bank 1 and 2 maximum. It’s usually if the car is warm it happens Current stable:
2006 BMW M6
2007 4.2 V8 S/C FF
Gone:
2002 4.4 V8 FF

Definitely not lpg I had an expensive week last week not using it 👍 Current stable:
2006 BMW M6
2007 4.2 V8 S/C FF
Gone:
2002 4.4 V8 FF

The only way it could possibly be the lpg is if it kept pulling the fuel trims out - how many miles does it take for adaptations to reset? Current stable:
2006 BMW M6
2007 4.2 V8 S/C FF
Gone:
2002 4.4 V8 FF