L322 Engine light/misfire

Been pointed to this forum from the introduction area. Question below ref RR. L322 4.4 V8 petrol/LPG.
New problem which has been on going for a few months is my engine management light keeps coming on after a few miles of driving and when checking shows bank 2 running rich and numerous cylinder misfired. Looked at bank 2 today and found oil around spark plug on cylinder 8, clean oil up and will monitor but thinking could be a problem with inner rocker cover gasket. Any thought?

Cam cover gasket fails are very common, what diagnostics do you have ?
LPG is SaintV8's bag as well as others

quite easy to trigger a eml on a l322 running lpg, they are a very sensative & detect even a millisecond on changeover of fuels

Bank 2 will run rich if one of the cylinders isn't firing as it is pumping unburnt fuel into the exhaust.

The oil is the most likely suspect, how are/is the spark plug stem? The oil tracks up these and degrades the rubber insulation causing tracking. If you clean up the oil, change the plug(s) and replace any dodgy looking stems, the next thing on the list is to replace the rocker cover gaskets as you say.

A common cause of cover gasket failure is the PCV valve over pressuring the crankcase causing oil to blow past any lose/ill fitting seals or gaskets so it may pay to take a look at that and also the breather hoses too.

An L322 on LPG is a dream as long as the system has been installed and set up correctly. I have had mine 4 years now and the LPG system (fingers crossed) has never missed a beat, no changeover hiccups or anything!

Will is correct, the Engine ECU is very sensitive to any slight change in anything.....mine throws a Bank 2 Upstream sensor fault every now and then, but I do believe I have an iffy Lambda probe that throws a wobbly.

Clean up, check gaskets and stems, then look at the PCV valve and the breather hoses as first port of call.

Thank you all for your comments, I am using a Lynx diagnostic which is good except they do not use OBDII fault codes, so back up with a small hand held which can communicate with the engine control unit only.
Used this morning for a small trip and running well so will continue to monitor but will look into the other points you have raised.

Mine was also very twitchy. I used to tweak the LPG changover temp in the colder months to stop it playing silly beggers and throwing an EML. Also used to run a calibration every now and then to keep it in tune.
PCV valve and rocker gaskets are always a good idea.

Thought I'd update this issue but first apologies for taking a bit longer than intended, however whilst trying to sort this problem out my petrol pump decided to pack up! New one installed and running smoothly now.
When checking the PCV valve and breather hoses I noticed the one coming from the rocker cover had collapsed due to another pipe pushing down on it. Rerouted this breather pipe and after a few miles it has gone back to its proper shape. Now done over 80 mile via short journeys and no problems with eml coming on etc. Will continue to monitor and let you know if any issues.
Thanks again for your comments and help by far better than any advice I have received from a garage!! Cheers

Engine light came on again after a poor idle and slight misfire. Check spark plug in cylinder 8 and found a little oil so cleaned up and decided to replace the breather hoses linked to the PCV Valve. Whilst removing the pipes and the oil separator found that the bottom pipe from separator had failed. It was completely in half, totally degraded. So got new pipe to replace but a total PITA to carry out. However, got all pipes back on (after flushing through the separator).
Carried out a 20 mile test drive and must admit it ran really smoothly so hopefully that pipe has been the problem all along. Will monitor and update later

Hi steve 53,
Did u get your issue with misfire sorted? I have same issue with mine oiling number four plug (rear one on drivers side ) and a misfire. Not coil or plugs,I already changed those. did your breather hoses from the pcv valve help?

Still having problems with engine light and misfire, so took the next step and changed the PCV value. Whilst doing this found another pipe completely degraded (some bore pipe that goes under intake manifold and connect next to the pipe from the oil separator). To start this really made a difference she drove lovely with no other problems, then after about 300 mile got the dreaded engine light again, fault reading Bank 1 running lean. However over the last couple of day started getting misfire on start up from cold with reading showing bank 2 cylinders misfiring and bank 2 running rich!
Only minor oil showing around cylinder 8 on bank 2 I have not had the time to change the cam cover gasket as yet so could have some input in to problems but would not expect that much problems.
Any comments?

Only misfire i ever got on mine was a bent injector connector pin, bent by my good self by refitting the injector wiring box rather hurriedly after doing my cam cover gaskets.......cost me £140 to trace......(cos i'm sh!te at anything that involves wires!)
Rather ****ed off the would be buyer who flew up to purchase her the ONLY day she ever mis-behaved!

I still haven't got to the bottom of my misfire problem, we found there is poor compression and excess oil on number 8 cylinder, so in the process of removing that head st moment! Will post findings when i get a bit more investigation done- wish me luck! !

Hi Guys, sorry it took a while to get back, but just got my sick big RR back on the road yesterday. So the misfire problem on cylinder 8 was being caused by a burnt exhaust valve. Also had a gas injector down on another cylinder causing her to run lumpy when she was switching over to lpg. But after 2 new valves on that cylinder and a good 150mile drive to the coast and back today, all is good in the world of V8 4.4 and I'm feeling friendly towards her again! Hope this is of some help to a fellow owner out there another day.

wil2813 said:

quite easy to trigger a eml on a l322 running lpg, they are a very sensative & detect even a millisecond on changeover of fuels

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I had mine for 10 months and it never missed a beat re. Lpg, it was a Zavoli system iirc.
I have no real experience of Lpg other than that, but don't they need fuel trims tweaking periodically?

Paul McAdam said:

Hi Guys, sorry it took a while to get back, but just got my sick big RR back on the road yesterday. So the misfire problem on cylinder 8 was being caused by a burnt exhaust valve. Also had a gas injector down on another cylinder causing her to run lumpy when she was switching over to lpg. But after 2 new valves on that cylinder and a good 150mile drive to the coast and back today, all is good in the world of V8 4.4 and I'm feeling friendly towards her again! Hope this is of some help to a fellow owner out there another day.

Click to expand...

My condolences to your wallet but glad you got her fixed.