i havent since its been rebuilt. but i guess worth doing one jic.

Lighthouse after having all his valve seats done I’d hope it wasn’t that! Current stable:
2006 BMW M6
2007 4.2 V8 S/C FF
Gone:
2002 4.4 V8 FF

I would hope so, but was helping a friend recently with is jag 4.2 that has valves redone and we found a leak on one of the splark plugs due to a badly cut thread

ive bit the bullet and ordered a gap tool. next up will be replacing all the plugs because am not sure they have been for a while

7th cylinder, am guessing cylinder closest to passenger seat. the ignition coil boot is stuck in the actual plug. i cant get the plug out, fml.

ive gone for a drive, i now have rich codes on lpg.

Is that since changing the plugs and the rest of the coils? The lpg probably needs re calibrating it would have been fitted with partially worn valves this won’t be the case now.

Long nose pliers should do it...

Afaik on that engine the cylinder nos are as follows

Bulkhead
——————
7-8
5-6
3-4
1-2
————
Front Current stable:
2006 BMW M6
2007 4.2 V8 S/C FF
Gone:
2002 4.4 V8 FF

well the rich codes have gone away. back to the standard 1 lean code on bank 1.

Quote:

The lpg probably needs re calibrating it would have been fitted with partially worn valves this won’t be the case now.

It has been a few times. I think the issue is because the petrol isn't running right then calibrating the lpg to the petrol won't work well.

Hmm then cylinder 8 is where am , ive also got bank 1-2 mixed up if your diagram is right. I guess the issue is in cylinder 8 so theres not much room to get anything in there. Getting the coil out was a nightmare to start with. I think we can safely conclude its not the spark plugs.

time to get the air sensors done

I’d just do the air genuine denso and genuine denso o2 sensors upstream that pairing made the world of different to mine once i concluded with a smoke test there were no leaks - have you smoke tested recently? I have ordered some downstream sensors now as preventative maintenance as if the fronts were bad I imagine they arent the best Current stable:
2006 BMW M6
2007 4.2 V8 S/C FF
Gone:
2002 4.4 V8 FF

Last smoke test was a few months ago. I know my valve cover gasket is leaking or something is leaking oil near front of engine but has never shown up in smoke test. Might be time to get that addressed as well

shameless bump So the air sensors have arrived. i havent had time to fit them yet but i havent driven the car on purely petrol for a while. so i did so today. i noticed it was correcting super hard, am guessing my LPG needs resetting up, but thatll happen anyway because am swapping the Reducer and Injectors.

so far, no lean codes. could it of just been the spark plugs? if so I can return the air sensors and save myself 120quid that i'll need for the rear brakes and shoes since their squealing

ill drive it for a couple more days and see if they turn up, the fuel trims seem to be normalizing, once they do I have a feeling my GAP tool will arrive, in perfect time for me to clear the adaptations, then ill take it on a decent drive on petrol only so it learn correct.

when thats all done and with no issues ill move onto lpg. if issues arise ill replace the air sensors. i really wanna get that plug out as well, ill order a new coil and hopefully will have time this weekend to get the sucker out

What air sensors are you on about there is only one maf? Or are you including the o2 as well? Check the date on the maf if it’s original just change it or if it’s not denso Current stable:
2006 BMW M6
2007 4.2 V8 S/C FF
Gone:
2002 4.4 V8 FF

ive gotta stop being an idiot and calling it an air sensor Lambda sensor is what i mean.

maf seems fine. ill see how the next 100 miles go on it before i throw on anymore parts.

I’d just do them unless you get under there and they looks fairly recent if you don’t do them now and they are original they will prob need doing them in the not too distant future... I’m guessing there were only £100ish for the pair anyway it would be good preventative maintenance if nothing else Current stable:
2006 BMW M6
2007 4.2 V8 S/C FF
Gone:
2002 4.4 V8 FF

for now am just trying to get to an equilibrium. plus i wanna know exactly what fixed it. so if i add them now am not gonna know if its them or the plugs. with the plugs Ill need 1 new coil as well for the one with the broken boot

edit: i mean yeah the o2 sensors will go in. since engines at 130k miles and I don't think they've been replaced

edit2: checked both the mafs I have, neither are actually denso. I swear one looked original though but neither have any denso markings. time to order another one

I've had a similar "Lean on Bank" issue recently.
I had the supercharger off to replace the bearings just before lockdown (I have a spare snout for sale with new bearings and oil seal (standard pulley) if anyone needs one). I replaced all the gaskets, the PCV and the PCV pipe (boy they are expensive). Despite all this I still had the code.
I've now (temporarily) cured it! Its not elegant but it proved root cause! I bought 1.5M of 22mm ID braided rubber fuel hose and ran it from the supercharger/throttle body elbow connection up to the PCV. I have a couple of huge loops of pipe at the front and rear to stop the pipe collapsing. Fastened with jubilee clips at either end, the air leak seems to have gone and my lean code has gone too. Next step is to design something in rigid pipe that can be connected by a short length of rubber hose either end.
So actual root cause? I think that both the new and the old OE hoses leaked at the throttle body end. I could make it worse or better by wiggling it.
Hope this helps someone. Rob 05 L322 4.2SC
2016 Discovery 4 Graphite
Lotus Carlton
Ascona 400
Volvo V70R AWD manual
Suzuki 1200 Bandit
Velocette Venom
BMW R80/7
Daimler V8 250
Mini Cooper S Works 2006