Noted-both - I see that the delay is 40 seconds - not long but the other setting that is involved is presumably the 1600 rpm changeover and on these short stop trips it sometimes takes a while to exceed 1600 - I suppose I could blip the throttle ! but use more petrol again !

Expect you guys have been through all this years ago ..............

Thanks Morat - I think it makes sense for me because I shop and stop at about 4 places on the coast and the air temp is around 34 so the engine does not cool very quickly - at least the system sounds like it is clever enough to decide if I give it the option. A story (shows my stupidity) - parked in an underground car park to have a meal out and when I came back car would not start. Realised there was something wrong like fuel and had to leave the car - get a lift home then next day a recovery vehicle - not easy in the car park only about 10 cm clearance and explain to parking man that I had been unable to move car - he let me off with a lower park charge ! Taken to my favourite garage guy who announced the petrol pump had had it. Then I remembered that I could have started it on gas and saved all the expense and agro - ..............................

One other thing - do you think I should select the option 'Start on gas with hot engine' - with the short journeys here and the heat in Spain it would save some petrol or are there other considerations ?

Yes but perhaps heat and vibration was enough to open it up more. Anyway, been on quite arduous journeys today and it is performing as normal. Steve at Jaymic pointed out that my readings which I posted showed that system was set for 8 cylinder in line instead of V8 which is shown by the number of boxes for Tin gas and Tin petrol which should be 2 each and this is set by the lambda screen and selecting 2 instead of 1. This has probably been the case since installation - Also he suggested that reducer pressure setting of 1.1 should be 1.4 bar. In fact he said the system needs a re MAP calibration but not to worry if it is ok with the above changes. He confirmed that it should be possible to blow through the inlet filter which I was unable to do so am leaving it out until replacement arrives. So pleased to have it running on gas again !

Well the pipe is not in too bad condition and all I did was rob a spring clip from the vacuum pipe on the plenum chamber and it is secure and holds ok. It does seem that the loss which one could hear as a slight hiss was enough. When I took the pipe right off to put the clip on there was lots of pressure in it and that startled me but enabled me to confirm that there was good pressure to the injectors. There could still be a something not up to scratch in the pressure sensor but for the moment it works. All this help and having to explore the problem has shown me the steps to take to find out the cause. Anyone having a similar problem I would say - power up the tank and input solenoid, take off the feed into the injector - at least then one can confirm that everything in the line appears ok. The software showed the pressure dropping as I increased the rpm so it was finding its way out at that connector.

Right - you will all be relieved to hear that with your help the problem is solved - crossing fingers tightly ! This morning I put 12 volts on the tank solenoid and with the plunger out on the reducer confirmed that there was plenty of gas at the injectors. But I found that gas was leaking from the tube fitting on the injector that leads to the AEB025 Pressure sensor which has been ok for ten years but I must have dislodged it changing the plugs. The problem started then. Also it was never fitted with a spring clip as all the other joints are so was able to leak. The leak must have been sufficient for the pressure sensor to register a low reading and shut off the solenoid. Been on a 30 min road test up and down the hills and so far it is ok. Still have to be sure that the crack on the input solenoid will allow it to work until I can replace it. Thanks to all who have taught me loads about the system - as the car and I are getting older with no hope of a replacement I'm going to need the knowledge.

Thanks LPGc - I didn't come across the errors on diagnostic so thought it was my fault but perhaps the software does not include it. The current normal mode is that it refuses to go across to gas when I press the button -green light blinks for a while then alarms - often straight away. Having said that, yesterday I took out the liquid filter and solenoid plunger and it went across to gas and I drove around the hill here for 10-15 mins on gas at fairly slow speeds (idling was not noticeably a problem) and was just congratulating myself on fixing it. Then, just as I was explaining to a puzzled Spanish neighbour why he could see me driving pointlessly over the mountains with next to no clothes on, the alarm went (idling at the time) and I came back very disappointed. But this could point to a faulty AEB025 couldn't it ? I've heard that the reducer tends to let more gas out when faulty if anything.
On the AEB025 The pressure P tube goes to the nearest injector and the vacuum V tube goes to the top plenum? chamber. next to two bigger tubes.

I was going to go over old steps - power the tank solenoid (engine stopped) undo the pipe at reducer to judge if tank pressure is really getting there - only a judgement I imagine it is similar in strength to when disconnecting the adapter filler at the gas station. Then, knowing that the inlet solenoid is not a problem when plunger was removed perhaps it is the reducer or pressure sensor. On my test pics posted earlier you noticed that the pressure fell off as the RPM increased and that it alarmed off up in the 3000 rpm region. More than this I'm stumped.

Seems good advice - I should have mentioned that the pressure sensor is the later type AEB 025 - actually shows on the diagnostic pics I think

As a follow up I did download a picture instruction for servicing/cleaning the Matrix injector block. Did not want to have to start that unless needed , but do they get blocked after ten years - what do you think ?

And I have just checked and realise there is a cable going into the block - would a low pressure problem in the injector block be read by the pressure sensor at that stage ?
This system is more complicated than I realised - I suppose the diagnostics does not read injector problems ?

I see on the Zavoli Tech Man software there is an error page which I never reached that includes Gas injectors - should I do this again and see if there is anything showing ?

Hi Gilbert - thanks makes sense but I should add that the pipe from the Matrix injector block to the pressure sensor is missing a clip at the block end and I was able to see bubbles (wetted the connection) from the pipe joint. Might this be sufficient to show low pressure at the sensor ? Did not realise there were solenoids in the Matrix injector. I see you say possible leak in feed to the injector ? I thought it was coming from low down on a pipe into the manifold - hard to hear exactly where but happens when I move the injector !

So we are back to the pressure sensor ? Or problem with the pick up pipe in tank - although there was some liquid under pressure when I loosened the input to solenoid...

I suppose, if I power the tank solenoid (engine not running) and loosen the input carefully I would be in no doubt that liquid pressure was reaching the reducer ?

I take the point about hoses for gas - but getting a bit disheartened here. As I said earlier when I started everything in the normal way with a meter on the solenoid supply and pressed button for gas as it reached correct temp and rpm, for a moment the meter showed 12 volts applied to solenoids but instantly switched off/dropped. When I powered the solenoids with separate 12 volts there seemed liquid pressure and gas pressure getting through but at the moment I switched to gas it failed. So is there a problem with the gas pressure sensor or the wiring for it ? I think the thinner rubber pipe from sensor to injector (matrix named thingy) also leaks as the clamp clip is missing from the tube. Is there a way of testing the pressure sensor - can I just apply some air pressure to it from air supply ? If I was in UK I'd just buy a replacement quickly but here it is a week to arrive if one is lucky. The first diagnostic leads never arrived and Tinleytech kindly sent another - Spanish post !!
Just to add - yes the diagnostic did show a drop in pressure as rpm increased - could this still be to do with leak - or faulty solenoid on reducer - have removed the plunger from it. The hiss of escaping gas was quite noticeable which happened when I moved the injector block with the four leads going to the inlet block. It was this batch of leads and tubes that I pulled around to get at the sparkplug change and after this the gas never worked.

The forum must be pretty bored by now of my adventures with the LPG but the knowledge and advice has been amazing - I shall soon be an expert ! Anyway, hoping that everyone learns something from our experiences here's where I'm at - Took the plunger out of the Reducer solenoid (so it would have no excuse not to pass gas) - powered both tank and reducer solenoid with 12 volts so they were technically 'open' (did this after starting car as it would not start when they were connected first) Warmed up the engine - pressed the gas changeover and got a fail as before as per low pressure - switched back to petrol turned off engine. Guessed that this meant the solenoids were ok so started playing with the pressure sensor with no particular plan but as I pulled the tubes and wires around there was a sudden hiss and smell of gas which I traced to the region of the pipes between the matrix and injectors (drivers side) . Every time I moved it a bit I could cause the gas to leak and stop - the pressure was getting quite low by then. I'm guessing that this could be my Low gas pressure problem which in turn closes the solenoids and shows on the diagnostics as low pressure. I remember that this problem only started after I pulled pipes and wires around in a bit of a temper trying to change the rearmost spark plug. So I'm crossing fingers that when i get back to it tomorrow this will be the answer. Now, does anyone know correct size of the fuel hose needed on my zavoli matrix to injectors ? I have some 12mm outer 6 mm inner in the tool box and hope it might do ! Gained so much knowledge from all the helpful advice !

I just blew through the filter and it seemed impossible to get air through it - perhaps it is designed only for very high liquid pressure - anyway, I have taken it out and will keep it out - then tested the solenoid which appears to work however I noticed the blue plastic body of the solenoid is cracked - tried the impedance but never sure what I'm doing with my meter. Could not get the solenoid plunger out as the brass keeper nut is very shallow and my ring spanner doesn't make enough contact but I could hear the plunger moving when I put 12 volts on the solenoid with two test wires. Started the engine full of hope but nothing has changed - still won't change to gas.

Right - with all the help here was brave enough to take out the liquid fuel filter on the reducer solenoid and used all my trumpet blowing powers to try and blow air through it - assuming blowing though bottom hole and blocking the opposite - not a peep !! Seems solid as a rock What should I expect ? So am replacing without the filter to test - we'll see - has been in there for about ten years ! Can't get the solenoid plunger out - the retaining nut has a tiny edge and ring spanner not making enough contact ......

Thanks LPGc - lots to think about. Once selected to gas it seems to cut off as soon as the changeover at sufficient revs is made. No idling phase. On motorway and roads at any speed it cuts almost instantly. There was one time about two weeks ago when it gave me about 7 miles on the motorway before beeping. It seems more complicated than I imagined. If I loosen the union where liquid comes into reducer and that is under high pressure does that mean that tube in tank is ok on bottom ? I have only done the basic diagnostic tests - I see there is an error screen - does that show more detail than just the readings ? I worry about the wiring and voltages because it was attacked by rats but it has worked for a long time after I repaired it. Campo rats - the price of living in Spain.

Well I laughed but am more frightened than ever to touch it now ! Actually - great info - have the same solenoid and filter so thanks both for pointing the way and the dangers. I have put my back out lying under the car and trying to remove front wheels by kicking from inside. They had jammed themselves on the hub (dirt and overtight nuts at last tyre place) - took an hour and WD40 galore to free them. If it was a wheel change by the roadside it would have been impossible......

By the way - to remove solenoid to get at plunger is it the little nut on the top of plate or the big one at base ? I'm plucking up courage, energy and knowledge before going up the steps to where the car is on the dirt track. If you saw my dog film on Youtube earlier post (no justification for forum but does show my two RR's for a second) you will see where I have to manage - no pit or garage and the sun is tough on cars - all the paint peels........

Sorry - seem to have missed loads of answers which were not showing when I started this morning - Thanks for how to remove solenoid - did not want to attack it until I knew the right way and I see answer about pressure so I'm going to check solenoid and blockages !! I'm a bit of a novice at this gas thing but pretty good at the air suspension having replaced/rebuilt all of it at low cost - but then on this forum I suspect the members did that years ago with a wave of a wand ............

Replaced the filter (vapour phase) about a year ago - but not sure where the liquid phase filter is ...........

Gilbert gave some pretty comprehensive info and I have checked what I can - managed to get 12 volts to the reducer solenoid and it seemed to work but very sluggish and no where near as noisy and active as the one on the tank. Is the pressure in the system because the gas is under pressure in the tank and allowed to find its way to the inlet manifold provided the solenoid is open and no blockage or is it dependent on getting the pressure from the reducer ? If the pressure is in the system anyway then either the solenoid and plunger are not operating correctly or there is a blockage somewhere. Is this a correct assumption ? All other pipework and wiring is as before when working ok.

I seem to have pressed on the wrong button as I meant to reply to Gilberts post not necessarily quote it all but it is very helpful and I need to ask some more. Have checked wiring and things I can get to, managed to get 12 volts to the solenoid on the reducer which sort of worked but did not seem as active as the one on the tank - it may be that the connection I was making was not very good. But what I want to ask is - does the pressure come from the simple fact that the gas in tank is under pressure and therefore makes its way to the intake manifold provided solenoids etc allow it or does the pressure get built by the reducer in addition. If the pressure is in the system all through then presumably I have a blockage or as suggested, a solenoid simply not opening ? Is it as simple as that ?