Mercedes LPG Conversion

[stewartw]

Hi I was wondering if any of the forum uses have had their Mercedes converted to run on LPG and if they have had and problems as a result.

 

[hairyg]

I've had two MBs converted.

The first was a 1996 C200 which was fitted with Landi kit. Fairly succesful but the low speed control on gas was very poor. Parking in tight spaces or driving on snow/ice had to be done on petrol. I did 70,000 miles on gas without anything untoward happening to the engine.

My current car is a 1994 R129 SL320 running with the Prinz system. This has proved to be much better than the Landi, I have to check the instruments to see which fuel I am burning as it is impossible to tell from the feel of the car. This car has done 40,000 miles since conversion without any problems.

The extra money for the Prinz system was well worth it and it means I can still enjoy the car now I am retired without draining the pension fund.

 

[turbopete]

newer systems also run through the fuel injection system, rather than just a gas mixer on the end of the inlet manifold to let the gas and air mix as it entered the manifold. ive seen an old system where the car backfired and the inlet manifold exploded as it was full of gas! newer systems are more expensive, but well worth it. no loss of power or mpg! old systems lost approx 10% of each!

 

[alindsay81]

whats the cost saving vs petrol over a years driving, including the cost of conversion ?

 

[wiltsandy]

I had my Cherokee converted with the Prinz system when I bought it just over two years ago and highly recommend it. I also went for an underslung tank with half size petrol tank so that I didn't lose any boot space.

Cost-wise I guess I get the equivalent of about 30-35mpg out of it which for a 4 litre isn't too bad. I've done about 20,000 miles with it fitted now but can't say whether I've broken even on the cost of the conversion as I've not worked the sums out!

 

[brianbrian]

Put a diesol engine in.

 

[hairyg]

whats the cost saving vs petrol over a years driving, including the cost of conversion ?

The SL cost £2100 to convert. I currently pay 51.9p/litre for Autogas and get about 95% of the mileage compared with petrol. You probably need to do 30,000 miles or so to get your money back on the conversion but you need to do the calculation for yourself.

 

[matteb63]

I have a 1999 E240 Elegance that I purchased two years ago with LPG conversion..We are getting 10p a mile without any noticeable difference in performance.We have saved half of what the car cost on fuel alone. Much cleaner than diesel and if you removed the cat converter you will notice better mpg and power..Flys through mot gas tests...
I also had a 1999 E320 40,000 miles converted for my father at a cost of £2100 in 2007..He reckons he has already recouped the cost of installation having covered 30,000
We also have a V class 230 lpg but am still working out its performance.Choose a good installer !

 

[r129co]

I have run an S500 for a year now on gas ...probably getting the equivalent of 32mpg in petrol terms. One of the problems has been a poor match of the nozzle sizes in the system to the hosing running to the components causing a few leaks..another turn on the jubilee clips sorts that. It does also put an extra loading on the HT side so keep ahead if you have a distributor model especially.
I have a mulipoint LPG system for a V8 only 8 months old if anyone wants one complete with tank for the spare wheel bay.

Carl

 

[stewartw]

Thanks for all the replies.

Has anybody had any problems with the conversions.

If so what was the problem? And how was it rectified.

Thanks guys

 

[shayes]

newer systems also run through the fuel injection system, rather than just a gas mixer on the end of the inlet manifold to let the gas and air mix as it entered the manifold. ive seen an old system where the car backfired and the inlet manifold exploded as it was full of gas! newer systems are more expensive, but well worth it. no loss of power or mpg! old systems lost approx 10% of each!

My car was converted in 2001 and I imagine has done many thousands of miles on LPG. I've only had it eight months. It is an older single point injection system and I saw the duct taped air box and was told there had been two "blowbacks" damaging the box. Not relevant to multi point systems. Not known if MAF sensor was damaged. I have fitted a blowback valve into the new air box. I find slow running on gas, tempramental. So, I usually switch back to petrol when likely to have to slow down in built up areas but fine on motorways. As long as I only change over to gas at low revs I have not experienced a blowback. I avoid using Kickdown, just in case. LPG may run hotter but I imagine it keeps the Cat clean and clears soot deposits. Happy with it except when the gun freezes to the knozzle! you sort of get used to the woosh of gas when disconnecting.

 

[MOR1809]

I had my ML320 2000 converted to lpg last year for £1200.00 including vat and this was done in one day.I got a 70lt underslung tank which is great.I get just over 250 miles per full tank which costs around £32.00. The only noticable thing there isa very slight loss of power(only noticeble to the enthusiast) but I have been told I need to decrease the plugs gap and that should make the car more fuel efficent and more responsive and no loss of power. I highly recommend the conversion as the price of petrol is only going one way and that's up and no congestion charge and 0 emmision.

 

[J.Smith]

LPG Conversion Problem

I had my ML320 converted in March 2008, for the past 4 months it has been playing up. The car actually runs really well on gas, my problem is that the system keeps switching over to petrol even though I have a full tank of LPG!

This has become very frustrating as it means I have to spend more money on petrol even with a full tank of gas!

I took it back to the dealer and he put it down to a diagnostic check and a firmware upgrade which was carried out there and then. A week later it started doing it again, I have yet to go back.

 

[rapide]

gas powered

Hi ,have look at the "arungas" website it has a conversion chart to work out how long it will take to get your money back on a given annual mileage , I have seen there work and some conversions and its spot on, I have an 210/ E230 and they do the boot donut tank that goes where the spare is / was! but on my mileage 3k a year it would take 7 years to break even and as i have now retired probably never! but its all food for thought . all the best, barry.

 

[matteb63]

I have had a similar problem in the past with engine suddenly switching to petrol with plenty of lpg..Having re attached the wires in the lpg/petrol switch attached to the dash somewhere, the problem cleared up so it may simply be loose wires in this little led petrol/lpg switch box.

 

[The Hooded Claw]

I have a soddin great Discovery V8 running on LPG to fill it up costs £50 & I get 320 miles ................... Now as you know its shaped like a Garden Shed so all in all I'm really really happy with it !!!!

The secret I've found is DO NOT go to places like Morrisons or LPG garages..seek out yer local GAS supplier, they are obligated to supply gas to vehicles who arrive on their premises ...

And in MY case the cost is 8P per litre CHEAPER!!!!

vis: Local Morrisons = 56p per litre........ Local Calor depot 48P per litre!!!!!!!!!

 

[hairyg]

I find slow running on gas, tempramental. So, I usually switch back to petrol when likely to have to slow down in built up areas but fine on motorways.

I had similar problems on the W202 C200 I had before the SL. Manouvering on LPG was difficult as the system was unresponsive at small throttle openings. The multi-point sequential on the SL is much, much better and well worth the extra money.

 

[cromarty]

I had my ML320 2000 converted to lpg last year for £1200.00 including vat and this was done in one day.I got a 70lt underslung tank which is great.I get just over 250 miles per full tank which costs around £32.00. The only noticable thing there isa very slight loss of power(only noticeble to the enthusiast) but I have been told I need to decrease the plugs gap and that should make the car more fuel efficent and more responsive and no loss of power. I highly recommend the conversion as the price of petrol is only going one way and that's up and no congestion charge and 0 emmision.

can you tell me which system you had fitted? i had a brc system fitted in august 2009 at a cost of £2000 and it turned out to be a nightmare. still not running properly. wonder if there are any other ml320's fitted with a brc system?

 

[AMck]

I had my ML320 converted in March 2008, for the past 4 months it has been playing up. The car actually runs really well on gas, my problem is that the system keeps switching over to petrol even though I have a full tank of LPG!

This has become very frustrating as it means I have to spend more money on petrol even with a full tank of gas!

I took it back to the dealer and he put it down to a diagnostic check and a firmware upgrade which was carried out there and then. A week later it started doing it again, I have yet to go back.

What system is it out of interest?

First thing I would check is the vaporiser - is it getting sufficient coolant. What can happen if coolant to vaporiser is poor it may heat up and switch to lpg. The lpg then draws heat to vaporise , which cools the vaporiser, reducing gas pressure and causes it to switch over to petrol again. When it happens stop and feel the vaporiser - it should be really hot. Also have a look at position of vaporiser it shouldn't be higher than the top level of coolant in the expansion tank.

Do you have the software and interface. If so get someone else to drive the car and monitor what the lpg system is doing.

 

[matteb63]

Congestion charges...It amazes me how many people believe that they can get free congestion charges...simply not true..unless your vehicle is listed under the models and makes that are exempt from the charge ,after conversion , I'm afraid you will have a sad moment when that penalty charge notice appears on your matt...
Check out Greencastle
http://www.greencarsite.co.uk/LPG-conversions-gas-car.htm
Check out the Powershift register..
http://www.energysavingtrust.org.uk...Other-services/City-schemes/Congestion-charge