I expect you have all been relieved not to hear about my P38 problems for a while but I think we all gain from sharing information don't we. Well, having at least got it to run on LPG again by securely connecting the pressure sensor pipe on the Matrix injector and without changing any more settings in the diagnostics, I thought I would take a break from it. The misfiring/rough running was as before but I could live with that if it meant not having to think about it for a while. Today I plucked up the energy and changed the 4 Magnecor ignition leads (only ten years old) on the passenger side only for some old used ordinary ones that I kept from my Classic and lo and behold the engine is much smoother and performs more like it's old self when very hot and going up a steep hill. On the basis of this I think I will treat it to a full set of new standard P38 leads. When I spoke to the Magnecor man he told me they were guaranteed for ten years ! To bear out what Lpgc and others have said, when I started as usual on petrol; it did not want to idle so I think it had reset itself to cope with the pre condition of ignition faults etc. I should just say that as usual with my P38 I found the cruise control vacuum rubber lead, which I had replaced before, broken so I rejoined - but the whole thing is perished and despite having loads of din numbers and clever writing on it is crap quality and I suspect made by some underhand company - used it on my Peugeot as well and it just falls apart in a year or so. But here is a question for you- if that vacuum lead is broken does it affect the running ? It has been broken for much of the cars life and running problems have only recently happened.
Nope, you find out who your true friends are though.....that was my expedition to Tunisia..........3 days before leaving a cog broke off the lay shaft in the gearbox - I took the engine out - took out the gearbox - went into London - Metamet - bought a spare lay shaft - reassembled and we were on our way by the monday ......now I can't even fix a Range Rover !!!
Hi Blue all makes very good sense - grateful for the logical summary - just wish it was as simple as my Willys Jeep when I was 17 - only had to hit it with the right size hammer .........
Oh I see thanks - I jumped the gun and thought that Blueplastic was suggesting that the rough running was brought on by the Petrol system retrimming to cope with LPG problems - I know its all sort of 'chicken and egg'. I'm happy to pursue the rough running because that seems the root of the problem. Driving along the motorway on gas at 70 is not bad but any of you would sense straight away that there is a problem and it is similar to misfiring - so checking leads next .........
Ok - that seems clear - it seems dammed if you do and dammed if you don't !! I notice when I changed the setting to the V8 2 banks lambda the No 1 is up around 4.2 volts but the No 2 is much lower - less than half - is that something I can or should adjust ? On the Modify carb screen I have not touched anything and don't understand it !
So what you are saying is that if everything is right on the normal engine running petrol side it trims itself and then when one adjusts the LPG it matches up and all's well ?
I'm beginning to realise that the more I find out the less I understand. I thought that the petrol side of things was completely separate from the gas. And that one adjusts the gas with the software. Does the LPG software make changes to the petrol config as well ? For years it was working fine on both then some months ago I had this misfiring /rough running problem that was common to both systems and got worse when the engine got really hot here. For the last 6 weeks it has been running on petrol because of the pressure sensor pipe leak so if the petrol has to 'settle down' it surely had long enough. Having fixed the gas problem of the leak and made small changes like pressure setting from 1-1 to 1-5 and lambda 2 the car is showing exactly the same fault as before on both systems Are you saying that there are changes necessary to the petrol system and do I set these up through the LPG software and what would they be ? Sorry to be so daft !
Gosh Simon - sounds even more complicated than I imagined - for the moment, having done a good road test yesterday where it behaved as normal I'm going to move back to the original problem which caused me to dislodge the gas pipe and stop the LPG from working in the first place. This was the rough running problem but perhaps I have to move to a different topic ? On both petrol and gas as the engine heats up I get rough running and lack of power as if misfiring especially at low revs - changed the coil pack (for a second hand one) - renewed spark plugs but didn't change Magnecor leads (ten years old) yet. Nothing shows up on the basic diagnostic (not a full rovercom thingy) at my local little shed in wilderness garage, good English guy. So I'm going to play around with leads and hope its nothing to do with crankshaft timing sensors or any other sort of clever device !
Chris
Thanks Orange b for info about recal very reassuring - I do have some problems with ignition leads etc rough running so will wait....
You may laugh but one of my jobs before google came along was a complete two way film survey of all Lancashire A roads and motorways for the Highways Agency - special mounted camera inside Range Rover classic - filming only possible with no rain ! This is the car that saw every road in Lancashire ! 
This is on the mountains near me here..........Sierra Almijara........not a road in sight !
That by the way is not the P38 with the LPG. It has long gone to RR heaven but I still have a Classic here in need of TLC !
Just to show you that once upon a time I was on top of the job..........
Thanks - if I had to, do you think that I could do a recalibration with the equipment and knowledge I have and forum help or is it something to avoid ?
So can i just increase the pressure setting from 1.4 to 1.5 for the moment ? As far as I can see the system has been running at 1.1 since installation for ten years if the first diagnostics that I did the other day is anything to go by. I realise a remap is necessary if changes are made ? Or could the diagnostics have given a wrong reading ?
I don't see a place in the Zavoli software where one can enter the reducer type !
Think I have the S but then I have to do a remap and all that !
Thanks Simon - only just seen your info - very comprehensive - counting my blessings for finding people who have this secret knowledge and so geared to my particular set up. Food for lots of thought so I shall buckle down and think !!
Very impressed ! So much to learn about these things. Trying to think - should I set the pressure back to 1.1 ? Does this weaken the mix and give it what it needs ? Where does one see what the reducer is 'set to provide'. Is this the 1.4 I have changed from 1.1 . ( And where/what is reference pressure?) Do I go to the MAP screen with all those numbers to get an answer ? I study the Tech Manual but as you can guess don't understand all the implications of it. Going round in circles here.........
Does the reducer have a fixed pressure output that must simply be matched by the pressure setting and if so how does one know what the pressure is ?
I spoke to Steve because my installation came from them and it would be reassuring to know that any spares will still be available after such a time. I have ordered new filter and solenoid from Zavoli now. Still trying to understand the logic of the diagnostic and setup software. If the reducer pressure setting makes no difference why can it be set or changed ? I can understand the business of 4 cylinder and single coil giving the necessary rpm output. What I don't understand is this - If you select auto calibration where does the programme get its info from - is it stored in the programme as supplied and if so how does it know info like number of cylinders etc ? Or does it just tune to the info one has already set in ? I made some changes like the rpm threshold to 1200 and that reducer bar to 1.4 also told it 2 lambdas and now it idles a bit unevenly and if I leave it idling it returns to petrol of its own accord.. I have some rough running issues with both petrol and gas which I put down to ignition leads/etc but it never changed to petrol of its own accord until I made those changes - any ideas ?
Ah yes - I deleted the bit in brackets which said 'picture title' because I had the same at start of link. Thanks - now I have another puzzle which will exercise the best of you. Just been trying to make some changes with the diagnostic software as suggested by Steve i.e. Reducer bar was reading 1.1 - he said change to 1.4 which i did but as soon as I click on next bit to change it reverts back to 1.1 . This happens with all the settings I tried to change except the 2 lambda setting which has shown on all screens. What am I doing wrong ? Tried with engine off - same thing. The diagnostic lead was well and truly chewed by the rats and I repaired it - I think - it works in other ways but perhaps some vital bit is not connected ? Or am I missing something simple here ? You can see the sand and dirt problem here in Spain in my engine compartment !
Having queried the problem with change of data I've now been told that it is necessary to press the 'Enter' key on the laptop before moving on to the next setting - just didn't think of that !
Ok thanks - dog walking time now on the mountain - 35 degrees - sun just dipping.
Slightly different point - how does one get a picture to show on here ? I know there is Pic add button but that seems to require an upload to an external picture site like imgur and then it shows only as a link. But some I have seen here appear on the screen direct.