Koppla isär gasledningar

[turbofolkan]

Hej på er,

Vår CNG Golf variant börjar bli tjurigare och tjurigare att starta nu efter 15000 mil. Tänkte ge mig på att byta tändstift på den, då det säkert inte är gjort på minst 6000mil, och då måste man plocka bort insuget på den motorn. Är det någon som vet hur det är med gasledningar och sånt fram till motorn? Är det bara att plocka isär dom, och sen sätta ihop dom och det blir tätt? Måste man se till att det inte finns något tryck eller liknande innan? Aldrig mekat med just gasdelen av bilen så helt känns plötsligt känner jag mig helt novis igen.... Som när man skulle meka moppe första gången!

För övrigt drar motorn en del olja, dryga litern på 1000 mil kanske, men efter vad jag förstår ska inte det vara något anmärkningsvärt enligt Volkswagen. Någon annan med VW's 2.0 Bifuel (golf och Touran alltså) som har erfarenhet av det?

[Hewey]

Hello,

I guess it's already about the time to change new spark plugs I would recommend NGK:s iridium-platinum stuff that they developed specifically to outlast the CNG environment. LPG Laserline is the brand name. Some have ordered them from the internet quite cheap (there is a link in earlier discussions), I had to pay quite a lot for the local dealer. Anyhow, don't wear out your ignition coils by driving with old spark plugs. If the plugs are not premium CNG stuff, it would be better to change them more like every 3000 mil or so. Otherwise you will be changing also ignition coils shortly. And they cost a bit more.

Best Regards, Hewey

[Hewey]

About the oil consumption, what oil do you use? I think my car (V70, 23500 mils) consumes almost the same, and the consumption increases as the oil ages up. I use Mobil 1 0W-40 SuperSyn, and I guess these kind of flowing, winter-proof oils just go through anything, especially when the stiffing polymers start to break during the use.

Best Regards, Hewey

[turbofolkan]

Hi Hewey,

I bought NGK PZFR5D11 spark plugs, and they are indeed platina. I had to pay close to €80 for a pack of 4, so I think they are quite expensive. For a full explanation see this page; http://www.ngk.se/upload/Martin%20bilde ... 20sid2.pdf
Anyways, I haven't had time to replace them yet, but hopefully will this coming weekend. I will update this post afterwards.
Concerning the oil issue; I use a semisynthetic oil because in my experience that one isn't consumed as fast.
I haven't run a scientific test or anything, it's just a hunch.

I'll keep you updated!

[turbofolkan]

Sådär ja, nu var äntligen stiften bytta. Förra veckan i och för sig...
Var mycket riktigt tvungen att lossa insuget för att komma åt i synnerhet 3:ans stift. Men jag behövde aldrig koppla isär gasledningarna, så det jobbet slapp jag. Dessvärre gjorde det ingen direkt skillnad på startegenskaperna, men det syntes på stiften att det var dags att byta i alla fall. Kanske inte så konstigt när de gått 4000mil "för långt"...

[Hewey]

Well, anyhow it's better to keep the spark plug condition on the safe side, so the ignition coils will live atleast a decent amount of time.

One thing that I recently discovered that could be also relating to our problems is written out nicely here:

http://www.volvoforums.org.uk/showthread.php?t=49683

Does the VW also start the engine always first with petrol? If so, maybe the petrol injectors could be the problem. It makes sense that the petrol injectors can be easily stucked with dirt as they are not in use most of the time. Then when you try to start your car with petrol, and the spray patterns are weak / dead / injectors leak when shut / etc, no wonder if the engine will not work properly. How is the car running with petrol, is it otherwise good with petrol, or is it just starting that is bad?

You could try some injector cleaning additive that is added into petrol tank, but don't expect too much from them. Atleast I did not get much of results when I tried. Now I'm thinking about the same kind of proper cleaning that is described in the link. Here in Finland there are a few places where they do it properly (about 15 - 30 € per injector), and I would guess that you have similar places in Sweden too.

This is again just guessing, but what else we can do? Give our gas cars to expensive mechanics that just start replacing expensive parts until the problems hopefully go away? Atleast we owners try to understand our cars.

Best Regards, Hewey