Changing the filters and checking for flapping or deteriorated pipes is the easy bit. Checking the calibration is slightly more difficult but can be done by looking at the long and short term trims when running on petrol and comparing them with running on gas. If you detect a problem here, then it really does need to go to someone that has the software and knowledge to set it up properly. If you don't have a means of checking the trims, there is a crude way of doing it using the trip computer, but more of that later.
To understand how the gas system works in a car, you need a basic understanding of how the petrol injection system works so we’ll start there. Petrol is pumped from the tank to the engine where it goes through a pressure regulator. This keeps the fuel at a constant set pressure and returns excess fuel back to the tank (pressure regulator is on the back of the fuel rail on a GEMS but integrated with the in-tank fuel pump on a Thor). The fuel under pressure sits at the back of the fuel injectors which are nothing more complicated than electrically operated valves. Think of them like bathtaps but capable of being turned on and off very quickly.
The injectors are switched on and off, to open and close them, by the cars petrol ECU. It takes signals from various sensors, engine temperature, intake air temperature, throttle position, engine revs and, by using an internally programmed ‘map’ knows how much fuel is needed at any one time. The amount of fuel is altered by altering the amount of time that the injectors stay open for. At idle, it can be as short a time as 2mS (2 milliseconds, or 0.002 of a second), at full throttle under load, it can be as long as 15mS. As the fuel is at a set, known pressure, the length of time that the injectors are open for directly affects the quantity of fuel injected.
As a check, the engine is fitted with lambda sensors in the exhaust system. These measure the amount of oxygen in the exhaust gasses and can tell if the air/fuel ratio (the ‘mixture’) is correct or not. If it isn’t, the ECU will ‘fine tune’ the length of time the injectors are open for to keep the mixture correct and the engine running at maximum efficiency. This is the short term fuel trim but if there is a problem somewhere that causes the amount of fine tuning to be greater than a preset amount, the ECU alters the long term fuel trim so the short term is always flipping between a bit rich and a bit lean (the positive and negative fuel trims) So if the air filter gets a bit clogged, the mixture will be permanently rich (not enough air) so the short term trims will be going constantly negative to reduce the amount of fuel and get the fuel/air ratio correct again. This will cause the long term trims to go a little negative so the short term trims are back working either side of zero.
When running on gas, the pulses that would be used to open and close the petrol injectors are used to fire he LPG injectors instead. Again, you have a preset pressure so it is only the injector open tines that vary. However, due to them being a bit clunky, not as fast responding as petrol injectors and are injecting a vapour not a liquid, they need to be open for slightly longer that the petrol injectors would. Ideally they need to open between 1.2 and 1.5 times the duration of the petrol injectors. So if the petrol injectors need to be open for 3mS at idle and 15mS are full throttle, they'll need to be open for around 3.9mS at idle and 19mS at full throttle. This is done by the calibration in the LPG controller. It has a map stored and adds the additional time to the pulses from the petrol ECU and uses that to hold the LPG injectors open for the correct amount of time. But, if the calibration is wrong and instead of adding the required 4mS at full throttle, it is only adding 2mS, the mixture will be lean. This will be detected by the lambda sensors and fed back to the petrol ECU which will adjust the fuel trims, initially the short and then the long term so instead of a 15mS pulse, it sends a 17mS one to get the mixture correct again by giving a 19mS pulse duration.
So you can see that by looking at the long and short term trims when running on petrol and again when running on gas, you can see if the calibration is correct. If you've no way of looking at the trims, you can use the trip computer. The trip computer doesn't measure the amount of fuel you use but calculates it from the fuel trims so can give a good indication of something being correct or not. With the car running on petrol, reset the trip computer and go for a drive. Preferably 20 or 30 miles of mixed driving and at the end check the mpg figure it is displaying. Then reset the trip computer and do the exact same journey only running on gas this time. The displayed mpg figure should be the same. If it says you are doing more miles per gallon, then the petrol ECU is having to lean the mixture off (make the fuel trims go negative) so the gas ECU is adding too large a correction, if it says you are doing less miles per gallon, the petrol ECU is having to increase the petrol injector pulse lengths to get the mixture correct (make the fuel trims go positive) because the LPG controller isn't adding enough.
Simple really......
Huh??? It's only a 204 kb jpeg.......
Your target heights look a bit odd, usually the front and rear are different but the difference side to side is very small, 131 to 109 seems a hell of a difference.
Way more than 2.0 litre but I can't find anything that definitely says what size you need. Simon will probably drop in and confirm but I've always understood 6mm pipe is good enough for up to around 250 bhp so you should be OK. Even if you changed for 8mm pipe you'll probably find that the outlets on the solenoids are only 6mm anyway.
Now showing for me but takes a few seconds to load. Before it just sat there downloading......
Nope, new one on me but it's worth a try. It does beg the question of how are you supposed to know why a system isn't working if you can't connect to it without the engine running. Unless it just needs a pulse, in which case you could spin it over on the starter while trying to connect (or have it running on petrol I suppose). To answer your previous question though, I would say downstream of the filter as the temperature is likely to be more stable. Which is probably why the installation manual I emailed you says:
1.1.4 Gas Temperature Filter and Sensor
For a correct installation of these components:
- The gaseous-phase filter must be installed on the regulator output. As indicated in the
General Installation Manual, we recommend users to perform regular scheduled
replacements of the filters. - The temperature sensor must be installed near the gas injectors, right after the gas filter by
the regulator output.
On a DS it was a bit more complicated as the front brakes were inboard, but even then, a damn site easier than changing the handbrake pads on a Jag you just had to remove a few more bits to get to them.
I had a similar experience on the ID19. Drove for miles with a flat rear tyre and only realised when I could hear a strange noise while reversing with the window open.
2 or 3 points out is quite normal but 15 seems quite a bit out and I would have expected it to correct for that. The car does have to be sitting perfectly level though.
I'm only going on my own experience with two cars, both of which were plumbed in parallel when I first got them and both running single point so run on gas from a cold start. The Range Rover Classic would freeze the vaporiser within 300 yards if the ambient temperature was lower than about 5 degrees which made it flood the engine and die. The only way of getting it to restart was to switch to starting on gas, with the vaporiser solenoid disconnected and crank it over for ages with the throttle pedal on the floor. Once it had started and run on the gas that was still laying in there, I had to run on petrol until everything had thawed out. The P38 never suffered from freezing but the heater would drop to lukewarm when sitting in traffic at idle on a cold day. Not pleasant when sitting in a queue for a car park while trying to go to do my Christmas shopping!
So it seemed that on the Classic I was getting more flow through the heater but on the P38 more was going through the vaporiser. Changing both to series plumbing meant that both got full flow and cured both problems. I agree that if a vaporiser has restricted flow it could have an adverse affect on the heater but that hasn't been my experience on the 3 cars I've tried it on. I did the same on the SE with it's eGas multipoint and that definitely allowed the vaporiser (reducer) to warm up quicker so it would switch to gas sooner with still no adverse affect on the heater.
Picture resized so it doesn't now choke.....
It's strange how we all seem to have gravitated to the P38. My first car was a Citroen Bijou, a Citroen UK designed and built plastic body on a 2CV floor and mechanics, that was followed by an ID19 Safari and after that a further 4 assorted DS models, culminating in a DS23EFi Pallas. All of them had the semi auto gearbox. Having watched the DS's rot away before my eyes, I went upmarket and bought a CX2000, followed by a CX2400 Safari only to discover that they rotted away just as quickly so went completely off piste with a Matra Bagheera.....
I've never quite recovered from the 'why buy something reliable when you can have something where making it to your destination is a bonus' mentality as I still own, just for the hell of it, a Maserati Biturbo Spider.
After swapping a known good valve block from one car to another I found that it didn't work. Squirted the big connector with contact cleaner, reconnected and everything started to work perfectly.
No, the ones Island sell are Dunlop so are the decent ones (even at only 50 quid a corner), it's the aftermarket ones that are crap. Having just looked though, it looks like you'd have difficulty buying anything other than genuine Dunlop, even eBay sellers are flogging the real thing. Not sure where the pair I fitted to the rear of mine came from when I first got it, but I never did get the nearside one to seal properly and they were both worn out and leaking within 40,000 miles.
I'm sure you'll have some somewhere. My tin looks like it's been kicked around the world at least twice and must be at least 20 years old but it's still just over half full. As it's safe to use on rubber, at least if it's meant to be used on brake seals, it must be safe to use on rubber, I use it on hoses, petrol injector seals and anything else rubbery.
Mace, changing the matrix involves either removing the complete heater unit or cutting bits of steel that get in the way to stop you from sliding it out and then having to somehow re-attach them. Changing the O rings is pretty simple (I've done it 3 times now on different cars and the last time took me 25 minutes) and worthwhile whereas changing the matrix is a only when it needs it job (in my opinion).
Maybe, but where it shows the most recent post, it definitely said that the most recent was in the Renewed Interior Filters thread by George B but there were no new posts in any threads at that time.
My first Range Rover was a '93 Classic LSE, the long wheelbase version with the 4.2 litre V8, bought from a mate of a mate. It was already running on LPG and would do around 14mpg giving the cost equivalent of around 28-30 mpg. The guy I bought it from replaced it with a 2.5DHSE P38. His wife loved it as everything insignificant (heater, electric windows, central locking, heated seats, etc) worked, which after the LSE where none of the above did, was considered by her to be a great step forward. He hated it. Compared with the LSE it was totally gutless so he thrashed it mercilessly to try to get something like the same performance as he was used to. As a result, the best he ever managed was 24 mpg so not only was it slower but cost more to run too. He now runs a Land Cruiser Amazon 4.7 litre on LPG.......
I usually use the red brake seal grease (known round here as raspberry jam grease) on new hoses so they slip on nice and easily.
Checking it is easy enough it you have a Nanocom or similar, if you don't you need one of these http://www.ebay.co.uk/itm/RANGE-ROVER-MKII-MK2-P38a-EAS-AIR-SUSPENSION-DIAGNOSTIC-FAULT-CODE-RESET-UK-/122229266441 (and, if you don't have an old computer with a serial port, a USB to serial adapter too if you don't already have one). I would suspect you have a dodgy height sensor so it is constantly trying to get the height correct. It woulod be a hell of a leak to empty the reservoir overnight.
I've also had new Dunlops come in Britpart boxes, I think they supply their own knock offs but will supply the real thing if that's what you ask for. Their cheap versions only have a single O ring in them so hardly ever seal properly.