if this thread is still alive then i have my own easy answer.

If i use the usual Shell, Esso, BP unleaded fuel i will 100% get the engine light illuminate after 2 minutes and a little lumpy running feeling.
If i use the V-max, Ulitmate or whatever higher grade fuel i don't get anything just a pure smooth running engine.

So for you techno persons it must be something to do with the quality of the burn ?
The LPG uses a pump to pressurise the rail ?
Does the normal fuel use the mixture bang to aid the pulling thro of the next fuel delivery?

I have no idea, just fill it up, press the loud pedal and aim it forward with a smile

LPG has a higher octane rating than petrol, so produces more power, it has a lower calorific value so you have to use more though... The check engine light has nothing to do with the quality of the LPG, it comes on for the reasons I stated earlier....

There are lots of different reasons why the check engine light comes on, yours seems to have a fault that needs sorting as it should run happily on very poor quality fuel, all Land Rovers are made to run on poor fuel as some of the markets they are sold in only have that.... Pete

__________________________________________________
2014 L405 Autobiography SDV8 4.4 Loire Blue Ebony interior
2011 L322 Vogue SE 4.4 TDV8 Baltic Blue. Parchment over Navy Interior. Sold
2012 L322 Autobiography 5.0 Supercharged Ipanema Sand, Jet Interior. Sold
2002 L322 Vogue 4.4 V8 Epson Green, Ivory over Aspen Interior (Fatty Offroader) Sold
-Click for Project Fatty off roader-

I have once had the same issue with my SC and it is due to go into the installer in the next few weeks for a check up and servic. I run a Prins system with valve lube.
The one time i had the check engine light come on was when the car had been parked up for 3 months and the light came on while changing from petrol to lpg. I stopped and read codes with IID and bank 1 and 2 running lean. Turned the lpg off and reset the codes ran just on petrol and after about 20 mins the light came on again with same faults. This made me think it was maybe a petrol issue because it had becone stagnent in the tank so ran the tank through and then put fresh petrol in and no more check engine light and it doesn't come on with lpg either.
This is only my experience and I think Pete's input is definately far more on the money but once your system is running correctly i would recommend running half a tank of petrol through once a month or so 2008 TDV8

Haylands, thank you for the information. Finallay decided to treat her to a full LPG service from a local garage. Managed to ask all the questions i have gained on this topic and satisfied with their answers that they're not just after the money etc.
I thought my system was running ok and it was until i noticed all the little comments on here and a few i am experiencing. Thanks to you all as it makes it easier for us less experienced people to ask and source the hopefully correct mechanics.
Will post the results later

Ningr...

jambo27 wrote:

i would recommend running half a tank of petrol through once a month or so

If it makes you feel better then fine but there is no need to do this...

A few points to make.... modern unleaded petrol starts to lose it's octane rating after about three months so don't keep the petrol tank full all the time....

LPG first came out in Australia donkeys years ago, they used to run solely on LPG, it would start on it no bother so the petrol side never got used.... then, people ran out of LPG after driving on it for three years solely on LPG and the car spat it's dummy out about working on petrol and left them stranded, that's when the LPG makers started making them start on LPG and not switch over until a preset temp.

The few minutes or so yours runs on petrol in the morning is plenty to keep the system working properly...

Although modern LPG systems are injection systems they run differently to petrol, the vaporiser turns the liquid LPG into gas and then delivers it to the injectors, it meters this by means of an internal diaphragm, after a while the diaphragm wears and changes the settings, this is the main reason for getting them serviced.. after a few years it will get a hole in it and then the car will run terribly... then it needs a new diaphragm or vaporiser depending on cost/availability... There are also filters in the system which get clogged with a thick brown tar like substance called "heavy ends" which is within all LPG but varies a lot dependant on quality of the LPG (which usually has nothing to do with how expensive it is)

My system which is a bit of a Heinz 57 with a Zavoli vaporiser and an AEB ECU runs great but took a lot of time to set up, the diaphragm holed earlier this year and it was cheaper to just buy another vaporiser for £47 than repair it. It was a 2009 unit so lasted 6 years but Zavoli are rather cheap and cheerful...

Makes me grin and means mine get's into double figures MPG sometimes....  Pete

__________________________________________________
2014 L405 Autobiography SDV8 4.4 Loire Blue Ebony interior
2011 L322 Vogue SE 4.4 TDV8 Baltic Blue. Parchment over Navy Interior. Sold
2012 L322 Autobiography 5.0 Supercharged Ipanema Sand, Jet Interior. Sold
2002 L322 Vogue 4.4 V8 Epson Green, Ivory over Aspen Interior (Fatty Offroader) Sold
-Click for Project Fatty off roader-

Hi, I read your article about LPG problems and I have the same at present. My L322 4.4 was running fine until it suddenly put the engine management light on, I thought it was a one off but no it has continued . I have had the car to a guy in Lincoln who has adjusted settings via his laptop but the fault return`s after a few miles and all I get from any garage that deal with LPG is how big is your wallet? it could be anything. I`ve changed 3 coils but no joy it still comes up with misfire, so if anybody knows a good LPG guy I`m more than happy to travel to him to get my RR put right, Barrie

Hi Barrie,

What system are you running as that will make a difference to the answers you receive as there are specialists in Prins, BRC etc out there.

regards

John

http://autogasyorkshire.co.uk/

Ask for Blair, he's ex British Aerospace and knows LPG well (don't think he actually did any planes though!!!!) Pete

__________________________________________________
2014 L405 Autobiography SDV8 4.4 Loire Blue Ebony interior
2011 L322 Vogue SE 4.4 TDV8 Baltic Blue. Parchment over Navy Interior. Sold
2012 L322 Autobiography 5.0 Supercharged Ipanema Sand, Jet Interior. Sold
2002 L322 Vogue 4.4 V8 Epson Green, Ivory over Aspen Interior (Fatty Offroader) Sold
-Click for Project Fatty off roader-

Hi again, the LPG system is Tartaini , and was running fine and I am very happy with the mpg, cheers Barrie.

Blair will sort it for you....  Pete

__________________________________________________
2014 L405 Autobiography SDV8 4.4 Loire Blue Ebony interior
2011 L322 Vogue SE 4.4 TDV8 Baltic Blue. Parchment over Navy Interior. Sold
2012 L322 Autobiography 5.0 Supercharged Ipanema Sand, Jet Interior. Sold
2002 L322 Vogue 4.4 V8 Epson Green, Ivory over Aspen Interior (Fatty Offroader) Sold
-Click for Project Fatty off roader-

Hi again, how do I contact Blair and discuss my problem with him ? cheers Barrie

Phone and email on his website - but no problem - have cut and pasted below.

Telephone: 01482 807506
Email: autogasone@gmail.com Howard
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2002 4.4 V8 LPG Tartarini
Have RSW AllComms in Cheshire J17 M6 - happy to help.
*Gone: Classic Vogue SE Auto V8 3.9

Hi, I rang Blair for a chat and booked my car in for a service , and although I`ve texted him and emailed his works to get directions and to confirm my booking I have had no reply, so he does not seem to be very reliable , is this normal because at this moment I`m not very impressed ,regards Barrie

Weird, never had any problem with him... mind you haven't spoken to him myself for a while...

Sorry about that, don't know what to recommend now...  Pete

__________________________________________________
2014 L405 Autobiography SDV8 4.4 Loire Blue Ebony interior
2011 L322 Vogue SE 4.4 TDV8 Baltic Blue. Parchment over Navy Interior. Sold
2012 L322 Autobiography 5.0 Supercharged Ipanema Sand, Jet Interior. Sold
2002 L322 Vogue 4.4 V8 Epson Green, Ivory over Aspen Interior (Fatty Offroader) Sold
-Click for Project Fatty off roader-

Hello Pete,and thanks for your reply, on the strength of the response from Blair and his company I don`t think I`ll risk an 2 hour plus drive to get them to service my car and I will look for someone a little more reliable, regards Barrie