Awad
Member
So basically I recently converted my Range Rover to LPG and a car on LPG should be at least 15MPG but mine is about 6.9MPG according to what the car says. The LPG conversion guy told me that it wouldnt use any petrol at all but yet it still is, I checked if it was leaking and it isnt. I calculated it myself and it was right. For a car running on LPG (maybe a bit of petrol) this MPG is awful. I have read many forums regarding this case and some people say that the thing that determines how much fuel to put in is faulty but if it was on my car it would have showed up on my dashboard but it doesnt so I doubt its that. In addition to this people saythat you cant just bdrive about 20 miles and calculate the MPG you have to drive until the tank is empty. I went to the LPG converter the other day and he told me I have to drive until the whole tank is emptied and see how many miles I have droven. I posted this same thread on YAHOO ANSWERS and only 3 people replied this:
hairguyuk2002 said:
LPG has less calorific value than petrol (less engine power on LPG) expect up to 20 % reduction, don't notice on a big engine car.
15 mpg down to 12 mpg, LPG can be bought at 50 p per litre ( flo gas not service stations ) petrol at 110 p per lt so fuel consumption equivalent to 12x2.2 = 26.4 mpg. 6.9 mpg isn't right take it back to the converter - how are you measuring mpg on gas? tank full run for 1000 miles measure gas used convert litres to gallons
Use single electrode (not iridium) plugs & reduced gap as a big spark is needed on gas, fit specialist lpg plugs see Amazon or e bay.
Ht leads and coil packs must to be in good order to get a big fat spark on lpg, with an older Range Rover & high miles might be worth checking.
Need a flash lube system fitted to prevent valve stem wear. If you have a cheap Polish conversion this may not be fitted. If the converter said you won't use any petrol you do on start up .A yearly safety check is required and replace lpg filter.
Source(s): I ran a BRC converted Rover 75 V6 for 200 K miles on gas, BRC quality injectors last 100 K miles cheap Polish conversions only 20K miles high milage drivers beware. Flash lube is essential to stop valve stem wear as lpg is a clean fuel without additives to lubricate valves.
I replied:
Hi hairguyuk2002,Thanks for replying.
What does the single electrode lpg plug do?
What I did to calculate the MPG, I filled up the LPG tank and the petrol tank, reset the miles droven to 00 (I dont mean the mileage) , drove the car for about 23.3 miles and filled both tanks again in the same station. I worked out the difference between the first time I filled up and the second time and that is how much I spent. Then I went to a website called http://www.fuel-economy.co.uk/calc.html and it asked for the: Fuel Cost: 54.9ppl lpg and 107.9 petrol
Total Spend: 10.43 lpg and 3.71 petrol
4.2 gallon lpg 0.5 gallons petrol
Distance Covered: 23.3 miles
and it said: Your real-world MPG average is 5.58, covering 23.3 miles using 4.18 gallons of fuel.
And is it spending too much fuel because the setup is wrong or is it because of the oxygen sensor, why does it do this? And my car is only 64k miles.So I want to know (and lets say it wasnt on lpg conversion) it is still spending too much fuel.
I'm Writing On a Dell Computer said:
my first recommendation would be to do the math, see if it is actually burning @ 6.9mpg or if the dash is just reading that out.
I replied:
yes it is actually burning 6.9mpg or lese lpg and petrol the same time also the dash is reading that
but if i am not mistaken even before the conversion to lpg. I calculated it myself and it was right. So the problems are too much petrol and lpg at the same time and I filled up the lpg when the
engine was hot enough to ONLY use LPG and the gas light was green which meant the car was running on LPG but yet it was still using petrol and LPG. The thing is that I drove the car for about 10 miles and it took 1 gallon petrol but for 23 miles it took 0.5 gallons of petrol and 4.2 gallons LPG
And does the dashboard give you the right answer, and how does the car know? How do I know if it is spending too much fuel because of the Ht leads and coil packs and the single electrode lpg spark plugs. Also how do I know if mine is good or not good. I dont think in my car there is lpg spark plug.
boy boy Said: the lpg system uses fuel ..until it reaches 50 degrees ..then the lpg kicks in ...checking up on range rover forums the car should do at least 17 mpg on lpg ...but reading the forum a lot of these conversions are very poorly set up ..yours sounds like one of them ..you need to get it checked by a specialis
I replied: The guy that converted my car had a 'uk verified lpg converter' certifacite or whatever and his company is nationwide.You wrote: the lpg system uses fuel ..until it reaches 50 degrees yes and it takes about 1.28mins-2.15mins, the lpg converter said that you cant calculate the MPG from 20 miles, you need to use the whole tank then do it again. Why do you have to use the whole tank, and not just about 20 miles?
I post on these forums because there is people who have knowledge and experience with many types of RR and LR vehicles more than Range Rover itself. I am really confused with this issue
. So please if you can help by just spending a bit of your time replying. I would really appreciate it.
Thanks
hairguyuk2002 said:
LPG has less calorific value than petrol (less engine power on LPG) expect up to 20 % reduction, don't notice on a big engine car.
15 mpg down to 12 mpg, LPG can be bought at 50 p per litre ( flo gas not service stations ) petrol at 110 p per lt so fuel consumption equivalent to 12x2.2 = 26.4 mpg. 6.9 mpg isn't right take it back to the converter - how are you measuring mpg on gas? tank full run for 1000 miles measure gas used convert litres to gallons
Use single electrode (not iridium) plugs & reduced gap as a big spark is needed on gas, fit specialist lpg plugs see Amazon or e bay.
Ht leads and coil packs must to be in good order to get a big fat spark on lpg, with an older Range Rover & high miles might be worth checking.
Need a flash lube system fitted to prevent valve stem wear. If you have a cheap Polish conversion this may not be fitted. If the converter said you won't use any petrol you do on start up .A yearly safety check is required and replace lpg filter.
Source(s): I ran a BRC converted Rover 75 V6 for 200 K miles on gas, BRC quality injectors last 100 K miles cheap Polish conversions only 20K miles high milage drivers beware. Flash lube is essential to stop valve stem wear as lpg is a clean fuel without additives to lubricate valves.
I replied:
Hi hairguyuk2002,Thanks for replying.
What does the single electrode lpg plug do?
What I did to calculate the MPG, I filled up the LPG tank and the petrol tank, reset the miles droven to 00 (I dont mean the mileage) , drove the car for about 23.3 miles and filled both tanks again in the same station. I worked out the difference between the first time I filled up and the second time and that is how much I spent. Then I went to a website called http://www.fuel-economy.co.uk/calc.html and it asked for the: Fuel Cost: 54.9ppl lpg and 107.9 petrol
Total Spend: 10.43 lpg and 3.71 petrol
4.2 gallon lpg 0.5 gallons petrol
Distance Covered: 23.3 miles
and it said: Your real-world MPG average is 5.58, covering 23.3 miles using 4.18 gallons of fuel.
And is it spending too much fuel because the setup is wrong or is it because of the oxygen sensor, why does it do this? And my car is only 64k miles.So I want to know (and lets say it wasnt on lpg conversion) it is still spending too much fuel.
I'm Writing On a Dell Computer said:
my first recommendation would be to do the math, see if it is actually burning @ 6.9mpg or if the dash is just reading that out.
I replied:
yes it is actually burning 6.9mpg or lese lpg and petrol the same time also the dash is reading that
but if i am not mistaken even before the conversion to lpg. I calculated it myself and it was right. So the problems are too much petrol and lpg at the same time and I filled up the lpg when the
engine was hot enough to ONLY use LPG and the gas light was green which meant the car was running on LPG but yet it was still using petrol and LPG. The thing is that I drove the car for about 10 miles and it took 1 gallon petrol but for 23 miles it took 0.5 gallons of petrol and 4.2 gallons LPG
And does the dashboard give you the right answer, and how does the car know? How do I know if it is spending too much fuel because of the Ht leads and coil packs and the single electrode lpg spark plugs. Also how do I know if mine is good or not good. I dont think in my car there is lpg spark plug.
boy boy Said: the lpg system uses fuel ..until it reaches 50 degrees ..then the lpg kicks in ...checking up on range rover forums the car should do at least 17 mpg on lpg ...but reading the forum a lot of these conversions are very poorly set up ..yours sounds like one of them ..you need to get it checked by a specialis
I replied: The guy that converted my car had a 'uk verified lpg converter' certifacite or whatever and his company is nationwide.You wrote: the lpg system uses fuel ..until it reaches 50 degrees yes and it takes about 1.28mins-2.15mins, the lpg converter said that you cant calculate the MPG from 20 miles, you need to use the whole tank then do it again. Why do you have to use the whole tank, and not just about 20 miles?
I post on these forums because there is people who have knowledge and experience with many types of RR and LR vehicles more than Range Rover itself. I am really confused with this issue
Thanks
