LPG haters - please advise (post 62 & 80)

2779 Views 83 Replies 23 Participants Last post by Dave2302, 2 mo ago

Bohemian TopDown

Discussion Starter · 3 mo ago

So, I took a day off today and went to the best Mercedes mechanic in Prague (judging by the reviews) because of that horrible rattling metallic noise that I have every time the tachometer needle touches the 2500rpm, every gear, both accelerating or slowing down, with or without gear, even revving with the car stopped.

As soon as his dog stopped chewing my leg, he took a look at the engine, saw the lpg system, and said: I'm not touching this car until the LPG is removed. You're destroying the car this way, Mercedes are not intended to be converted. When you install an lgp system in a Mercedes the engine head must be replaced with something compatible with this gas, and here it has not be done.

Now, I bought this car already converted, and given the price of the gas here, I don't mind paying a third. I wouldn't have done it myself, but it was there already, and I must admit it works pretty well.

He didn't say anything about the noise, didn't even want to listen to it, he went on for 20 minutes just cursing the LPG (I left, probably he's still going on).

My concern now is that I'll never be able to have a mechanic, because my car is converted... And yes, I tried the LPG shop, they said no, we only deal with lpg related problems, this noise is not related, go find a mechanic.

Do you really think I should have the system removed? Am I destroying the engine? Is it that bad? I just wanted to get rid of that rattling noise (not the engine supports, got them checked), I'm quite happy with having the option to save some money when I don't need to score the best lap time on qualifying session... But if it's really that bad, I can live without.

Save

Reactions: 4

1 - 7 of 84 Posts

i860

· #16 · 3 mo ago

I have all my mercedes converted to lpg
slk 200
slk 350
c class 200
c class 280
Not one sigle engine problem.
Lost 8hp at the top end on my slk due to the lpg, mesured on dyno petrol vs lpg
I got it at 62k miles now is 115k and so far so goo
My wife c 280 i go it at 70k now it has 128k and all ok
In your case is a mechanical problem is not due to lpg, find a good mechanic.
I do a compresion test evey year same month and all ok so far.
Intake valves on lpg

People had this think about lpg that is bad, probably from old cars, but new cars have so many sensors if somethign is not ok you get a engine check light so you will blow your car only if you ignor it.
Also my slk 350 has benn remaped since 5 years and so far all ok.

See less See more

Save

Reactions: 5

i860

· #17 · 3 mo ago

jbanks15 said:
Do you really think I should have the system removed? Am I destroying the engine? Is it that bad?

Yes
Yes
Yes

If MB wanted a LPG version, they would have made 1

Well, iam disiponted, if you will came on the table with some arguments yes.
Is like me saying a supercharger was not intended for you slk 55...

Save

Reactions: 5

i860

· #22 · 3 mo ago

Turbo said:
Which is technically correct, the best KIND of correct .

That's why they, MB, created the M113k engine. Stronger parts, to take into account the added compression rate..

But just because something isn't designed for it, doesn't mean it's not a good idea.. Which have been proven .

On the lpg the problem could be the valve material ( but as we know MB made only good quality components see balance shaft, as intended of cours..) You burn the valves if you run lean, i you run lean lpg or petrol you have lambda probe to tell you that.
I will not go in any polemics but we are on a reputable forum and people are coming here for advices, poor or ritch ( as i was told long time by some one).
So your problem is not lpg related, slk 200, slk 280/350 all have faults, only bulletproof car is 55 less than transmision.

Save

Reactions: 5

i860

· #26 · 3 mo ago

In Eu they have lots of lpg station, in my case i have one in my village, if that goes busted the next one is 25miles. So for 50mile go and back there is no point having lpg.

Save

Reactions: 5

i860

· #61 · 2 mo ago

nemiro said:
LPG is actually good stuff. I had it on an old Ford pickup with a 351W, and after 200k miles, the inside of the engine was clean as a whistle. Spark plugs always looked brand new, without a trace of carbon anywhere.

LPG does make slightly less power, but you will be hard pressed to find the difference. The only issue I ever had with it was that it would sometimes be hard to start in cold weather. That probably had as much to do with the quality of the mixer I had than anything else. Other than that, I never had any issues with it, and never felt unsafe with it.

In my case the car always starts on petrol and when the water reaches 40deg then will swich on lpg.
I set tit up to swich on petronl @4700rmp and swich back on lpg under 2500rmp for the times when i really need to smoke my car.

Save

Reactions: 5

i860

· #73 · 2 mo ago (Edited)

I will no go for any of those as there software is locked and you can do anything on the lpg system.
Go with an open one, and you can play with lpg settings.
I have AGIS ecu, baraccuda injectors and kme gold reductor.
Installation and tunning is paramount ( injector position, hose lenght etc)
Also for pice o mind you can install an obd monitor like i have for stft and ltft inj time etc

Save

Reactions: 5

i860

· #76 · 2 mo ago

Ad B said:
Hi i860,
Good choice for you, but not for me.
I'm not educated enough to play with fuel management, nor LPG or petrol.
Companies like Prins has to develop those things for me, I don't want to worry about that.
I will do my maintenance myself, as long as it is to do with bolts and nuts, I like it.
Not to much electronics.

But on Pri

Ad B said:
Hi i860,
Good choice for you, but not for me.
I'm not educated enough to play with fuel management, nor LPG or petrol.
Companies like Prins has to develop those things for me, I don't want to worry about that.
I will do my maintenance myself, as long as it is to do with bolts and nuts, I like it.
Not to much electronics.

We learn, you save what is inside the cpu and then you start to play fi you want, but on prins you can even log in to ecu to make a simple diagnostic, you need to go to a authoriused garage, and here in uk.... no thank you .
You have the best lpg installer there so you are lucky.

Save

Reactions: 1

1 - 7 of 84 Posts

Top Contributors this Month