Hello, my first post here. Just got my first FFRR last week. Can anyone advise if this is normal or what could be a cause but from a full fill up of LPG 93ltr tank I'm only getting 115miles before it's completely empty.

Gosh that's not good.. Simple maths - 93 ltrs = 20 gallons , 115 miles / 20 = 6 mpg.

Something is very wrong , LPG does not give a big a 'bang' as petrol so does use a bit more. (I worked on a 20% deduction from my petrol figures) ..

What does your car do on petrol? Try a tank an see what that gives . Some of the petrol heads on here should give a more acurate figure for both .

If its bad on both or just LPG at leat you can start narrowing it down on where to look.

Cheers

Simon

Its worth noting that 20% of your LPG tank capacity is not usable . e.g. a 100L tanks has only 80l usable
I believe that what you can get into the tank may vary with temperature to more on hot days less on cold ones.

My 4.2 SC runs on petrol right now, but I have previously had 2 lpg converted cars, but they had 4 cylinder 2 litre engines, so don't really compare to the Range rover V8, However I got 350 miles on a 100l LPG tank in both. that was usually on a steady speed motorway trip from Glasgow to Bristol which is constant motorway all the way. (M8, M74, M6, M4 M32)

As the man said , if all is well with the system you should be getting mileage of about 20% less that petrol
so even at say 20MPG on petrol your lpg tank should give you about 250 miles maybe more depending on your driving style

As per what Blackstoun, above, says, there should be approximately 68 - 71 litres of LPG in the tank but 115 miles from a tank is not good. I've been running LPG for over a decade on my cars and I run a 4.4 at the moment and also a 1.4 Astra on LPG. Whilst it's fair to say I'm slightly disappointed with the MPG I've got generally from the FFRR, I've had extremes of 135 miles to 280 miles from my tank (compared to 500+ miles from 68 litres in the Astra). On average its giving about 200 miles but I have recently changed all 8 injectors for smaller flow units to test them but have retuned the system as well. I am working with an LPG installer in Solihull (Solihull Autogas) to see what the best setup is. He has an M62 powered 5 Series which gets 300 miles from 60 lites so the shape and the weight of the FFRR must be a serious factor. I am also in the process of changing all four lambda sensors for brand new bosch units to see if they are a cause of poor economy as the sensors are a replacement / service item. All of the spark plugs are also LPG plugs sourced from Oilman on this forum.

Therefore there are a number of things you need to check:

1. Air Flow meter in good order?
2. Spark plugs? When was the last service?
3. When was the last service of the LPG system
4. Are the engine breather pipes in good order?
5. Check that there are no air leaks on the engine
6. Are there or can you smell any gas in or around the car when the car is running? (To check for leaks on the injectors put a small amount of washing up liquid into a old bottle, add a bit of water, and then shake it and put the foam onto the injector points on the anifold and if it bubbles up, there's a leak)

If all of the above is ok then there could be the possibility of valve seat recession. You don't say what model of FFRR you have (obviously petrol) but valve seat recession is rare on the 4.4 BMW but more likely on the Jag engines so you could get the head tested as if the valves are stuck open then perfomance will suffer and so too will economy. I had this with a previous car and I imported special valves from Germany, rebuilt the head and it was fine thereafter.

You can see a list of 'problem' cars here http://www.amrautos.co.uk/database_problem_cars.pdf

I hope this helps?

Kind regards

John

I have a 100ltr tank of which 80ltr is available and I get around 215 miles per 80ltr

Hey thanks for all the replies so far, I've just realised that it flashing isn't empty its reserve (sorry i'm new to this whole LPG business) its still flashing and I'm closer to 150miles now, is that any better. Its the BMW 4.4 and seems to have been well looked after in the past (bought from sir alan sugar so I'm hoping it was maintained well, it only has 70,000 on the clock). The check coolant message came up yesterday and i checked and it was empty in the tank could that have anything to do with it? I've topped it up and praying there isn't a serious leak somewhere...but thats an issue for another area of the forum :O

Once again thanks for all your help so far

Yes, that's much better mileage.

The tank level issue is interesting as it can either be calibrated electronically or manually and it can also be affected, rather oddly, by the choice of solenoid used to activate the cut off valve usually located in the black metal unit attached to the LPG tank. You will also get used to using mileage rather than the fuel guage to determine the fuel level as in my Astra, when the fuel guage starts flashing, I've got about 140 miles in the tank. It 'should' be graduated in 20% increments and even manually it isn't accurate. Finally, the cold weather will also affect the guage as the colder it is, the lower the LPG level will be and also, the colder it is, the more fuel you will get into the tank when you refill. Therefore try and fill up on a cold day!

Finally, this map http://www.filllpg.co.uk/ will help you locate the nearest LPG stations to you and is especially useful on a long journey outside your normal filling area. Check that the stations are open though as the map depends on user updates.

I hope this helps?

regards

John

Angus.myers wrote:

Hello, my first post here. Just got my first FFRR last week. Can anyone advise if this is normal or what could be a cause but from a full fill up of LPG 93ltr tank I'm only getting 115miles before it's completely empty.

It the three tanks we've done in our new one we're getting 220-230miles per tank. Thats a 68/69l fill on an 85l tank.

As has been said you can't rely on the LPG level indicator, they're notoriously unreliable! Use miles in combination with the estimated fuel consumption to gauge your range.

I don't measure by the fuel light. I measure mileage from full to empty

@Angus

I get around 240 miles on a tank usage of c. 70L.

I find a good tip is to zero your trip counter milometer every time you fill to the brim with LPG. I know that when it gets to the red indicator, I have c. 100 miles left.

If it is flashing on my STAG system, then it means 2 things:

1. tank is empty
2. It is switching back to petrol as it is being starved and therefore needs adjustment in its settings.

had to fill up yesterday as i'd run out of LPG.

208 miles 71 litres with mostly london driving which is a bit better than i normally get in town.

Just got back from filling up 40p per litre at the moment.
On a bit of a run last week (tank not empty) and done 239 miles and fill up with 74 litres.
Around 12p per mile ... Not complaining with that

Normally I get around 250 mls on 70 ltr highway and 220 in town. AjV8

As others have said, the led lights are inaccurate. The only accurate method is to fill the tank. zero your tripmeter, then run it until it changes over to petrol - forget the "low" indicator, let it actually change over.
I usually do this a couple of times on a new-to-me vehicle. You might be surprised as to how much it can differ as well, given different driving conditions.

And, again as has been mentioned above, make sure your system is serviced properly. My current L322 gave me 150 miles, barely, twice when I first got it. Went for a full service, needed new injectors (ouch!) and the first time out after that I got 220 miles... Best Cheers

Frank
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"(o)======(o)" Range Rover 4.4 Vogue (with LPG)