Wasn't aware that Steve at Jaymic was registered on here but anyway, the pressure setting in the software should match the actual pressure setting so changing it will make no difference at all. Not familiar with the Zavoli software but if it is the same as other AEB based systems, you have to press Enter after making any changes or they don't happen. I'd be inclined to leave everything as it is, it worked so even though the settings are wrong, it won't make a difference. I've seen a singlepoint system on a P38 that had the software set as a 4 cylinder engine and single coil whereas it should be 8 cylinder and dual coil. Made no difference at all as it was only used to detect the engine rpm and a 4 cylinder engine with a single coil gave the same rpm readout as an 8 cylinder with dual coil.
The option to start on gas will be shown in modern software even if your ECU's firmware is too old to support it.. The option to start on gas may or may not actually work.
You've got to press enter for any changes you make to stick.
As you were told by Jaymic, if you make any changes to the pressure setting you will have to do a full re-calibration. The pressure setting is the pressure at which the system won't factor in any compensation for pressure when calculating gas injector pulse duration, i.e. if actual pressure reading is the same as the reference pressure you set in software it doesn't need to factor in any compensation for pressure being actually higher or lower than your reference pressure. A higher actual pressure than reference pressure will result in the LPG ECU pulsing gas injectors for less time and vice/versa. So, if you make changes to the reference pressure you also have to do a full remap. If you simply change reference pressure from 1.1 to 1.4 bar without doing a remap, the system will compensate for what it now sees is an under pressure situation by pulsing injectors for longer duration (1.4/1.1 = 1.27), so we might expect your mixture to be richer by around 25% unless you remap.
AEB systems are particularly good at compensating for pressure differences accurately. The following isn't to say that it would be a bad idea to change your reference pressure from 1.1 to 1.4 and re-calibrate but is something to consider especially if your system is older... Some of the older AEB systems don't allow you to set the pressure at which the system will switch back to petrol, on such systems (and behind the scenes) the change-back pressure is around 50% of the reference pressure, so that might be 0.55 bar with reference of 1.1 bar and 0.7 bar with reference of 1.4 bar. Your reducer is just about up to the job for fuelling a Rover V8 flat out but might expect pressure to drop a bit when flat out. If you set ref pressure to 1.4 bar, and if other factors are also at play, you may find it more likely to switch back to petrol when you put your foot down even though it might have been perfectly capable of running your engine flat out without switching to petrol. While (again) if you change that figure you'll have to do a full recal anyway. Save your config before making any changes anyway!
Simon
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 ?
As Simon explained, the reference pressure in the software is the pressure against which the ECU compares the current pressure to compensate for fluctuations in the supply. Your map is set to provide an injection pulse of x duration at y gas pressure where y is the setting your looking at. If the pressure reported by the sensor is y+/-z the ECU will make an adjustment to the injector duration to ensure the cylinder gets the correct amount of gas. Reference pressure should be set to match whatever the reducer is set to provide and if you go and change it to something other than the pressure the reducer is providing your ECU will be constantly correcting away from the value required by the map.
From what you said above, and Simon's post it sounds like your engine is now idling 25% rich.
At least, that's my understanding :)
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 ?
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 !!
super4 wrote:
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 ?
You don't and you don't need to. The pressure is set when it was installed by adjusting the Allen bolt on the reducer. Then you tell the software what pressure it is set to. Changing the figure in the software without physically adjusting the pressure on the reducer will just make things go out of kilter. It will be adjusting for a pressure that it thinks it is running at when it is actually running at a different pressure. The same goes for the Lambda setting. Yes, the car has two lambda sensors but are they both connected to the LPG system? It may be that only one of them is connected so 1 would have been correct.
Not sure whether you have the Zavoli Zeta reducer or not, but if you do, you need to identify whether you have a Zeta N or Zeta S and set the pressure in the software accordingly:
Think I have the S but then I have to do a remap and all that !
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 !
increase to 1.5. Then monitor the injector timings and fuel trims. Worst case scenario you'll need to do a recalibration but at least then it'll be setup correctly. Shouldn't need to pick the reducer type, just alter the pressure.
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 ?
super4 wrote:
Think I have the S but then I have to do a remap and all that !!
That is an S
You don't actually have to change any of your settings or do a remap as the system (I assume) ran OK before you pulled off the pipe?
You can tweak things around to reflect the correct settings/ equipment fit, but instead maybe just replace crusty pipes, cracked solenoid coils, filters etc and leave the rest alone. If it ain't broke etc.
Just to show you that once upon a time I was on top of the job..........
super4 wrote:
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
You could do an Auto Calibration after getting all of the config in line with what you do have but...
A main pre-condition to AutoCal is that the car is running spot on in Petrol- settled trims, all that kind of thing. If you're sure thats the case, AutoCal will get things in the ball park but you then need to tweak the maps to get it running right all across the range.
If it's already in the ball park (I love these Americanisms) anyway (as I said above) then why bother?
super4 wrote:
Just to show you that once upon a time I was on top of the job..........
That's a brilliant photo!
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 !
Google's Streetcam has come on a lot since the early days...
Orangebean wrote:
super4 wrote:
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
You could do an Auto Calibration after getting all of the config in line with what you do have but...
A main pre-condition to AutoCal is that the car is running spot on in Petrol- settled trims, all that kind of thing. If you're sure thats the case, AutoCal will get things in the ball park but you then need to tweak the maps to get it running right all across the range.
If it's already in the ball park (I love these Americanisms) anyway (as I said above) then why bother?
After sorting my leaky injectors, I knew that my LPG would need re-doing. Simon had pointed me in the direction of cables and said I should be able to do it myself. I left it a couple of days to get the petrol fuel trims right and then had a look at it. I tweaked the settings Simon had already done and thought I had it right, but within a couple of days it was running like shite. Bank 2 o2 kept going off as the fuel trims had gone beyond the range. Bank 1 never moved though. I messed about with it over the course of a week but to no avail. Finally I decided to do a new calibration. I ran it on petrol for a couple of days until everything was running real nice. As Orangebean says, it must be running right on petrol first. I set the auto calibration going and followed the onscreen instructions. Piece of cake and done in less than 10 minutes. I haven't had to tweak anything and I think it's running smashing. Been good for 2 weeks now with no problems.
Don't be afraid of having a go yourself.
Save the current configuration first. If you bugger anything up, just revert to that.
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 !