Auto-LPG and sparkplugs...

**ghosthunter** · January 14th, 2011 11:00 PM

Originally Posted by kikoteng

About running leaner, I try to lessen the LPG flow to minimize smell of LPG from exhaust especially during startup. I am assuming though that having the smell of LPG means the LPG flow is too rich. Would that be a correct assumption ?

roughly correct but your nose is not precise enough to measure how lean or rich your air-fuel mix is.

Actually, it only happened with the Bosch regular temp platinum plugs. Never with the other plugs. The sound would be only single pops. It sounds more like a 'triangulo' and it happened twice yesterday while accelerating along SLEX.

Been driving car the whole day yesterday. No problems until I was on my way home. The only thing I can think of is that the car has been in use for 2+ hours.

Might be your engine is running lean causing a hot spot to happen resulting in pre-ignition. Adjusting for more fuel flow should correct the problem.

**kikoteng** · January 14th, 2011 11:09 PM

Originally Posted by ghosthunter

roughly correct but your nose is not precise enough to measure how lean or rich your air-fuel mix is.

Might be your engine is running lean causing a hot spot to happen resulting in pre-ignition. Adjusting for more fuel flow should correct the problem.

Any idea (DIY method) on how to set the correct air-fuel mix for LPG ?

**ghosthunter** · January 14th, 2011 11:20 PM

Originally Posted by kikoteng

Any idea (DIY method) on how to set the correct air-fuel mix for LPG ?

why not just look for a Auto-LPG station that offers "free" LPG tuning if you buy fuel from them?

CLEANFUEL (shaw) offers this service.

**kikoteng** · January 14th, 2011 11:53 PM

Originally Posted by ghosthunter

why not just look for a Auto-LPG station that offers "free" LPG tuning if you buy fuel from them?

CLEANFUEL (shaw) offers this service.

Didnt know about that. Thanks for the info.

**vinj** · January 25th, 2011 01:32 PM

Right now i'm using the NGK BKR GAS which is designed for LPG and CNG vehicles.

Its running well with FC still consistent when i was using BKR6E-GPs however i noticed the car hard starts when i run it on gasoline for extended periods.

Saw NGK BKR7E's (two step colder than stock) so i'll try these out just as well on my next plug change.

**vernieg** · February 15th, 2011 01:25 PM

Nakakita na ako ng Bosch platinum spark plugs on a daily driven taxi na after six months of using lpg sira na ang negative electrode ng spark plug due to acidic type of corrosion. Same thing will happen to upper cylinder block over time, mas mauna nga lang ang spark plug. Such corrosion did not happened to gasoline engines. It is a fuel combustion by product issue and not a fuel-air mixture issue.

Ask an experienced mekaniko or visit their shop, those who have serviced cars running lpg, they will tell you the real story about cars using lpg. Other than health problems experienced by taxi drivers using lpg, this corrosion issue is a big problem for car owners.

Fortunately, nag sulpotan na ngayon ang mga spark plugs for LPG use.

example:
http://www.bosch.com.au/content/language1/html/6578.htm

Unfortunately, the upper cylinder block replacement ay hindi madali mahanap unless daming surplus na pumapasok. Kahit meron mang supply ng upper cylinder block, it is not still practical to have it replaced from time to time.

Did anyone question about the quality of lpg fuel used for cars here in our country? I hope someone will.

Originally Posted by ghosthunter

I have noticed with some of our cars equipped with SGI-AutoLPG.

The cars with SGI Auto-LPG systems have a tendency to "wear out" sparkplugs resulting in uneven idle, power loss or even engine stalling.

**ghosthunter** · February 15th, 2011 02:47 PM

Originally Posted by vernieg

Nakakita na ako ng Bosch platinum spark plugs on a daily driven taxi na after six months of using lpg sira na ang negative electrode ng spark plug due to acidic type of corrosion. Same thing will happen to upper cylinder block over time, mas mauna nga lang ang spark plug. Such corrosion did not happened to gasoline engines. It is a fuel combustion by product issue and not a fuel-air mixture issue.

Ask an experienced mekaniko or visit their shop, those who have serviced cars running lpg, they will tell you the real story about cars using lpg. Other than health problems experienced by taxi drivers using lpg, this corrosion issue is a big problem for car owners.

I am still more convinced that the so-called corrosion is actually pitting caused by detonation due to improper air/fuel mixtures. Richer mixtures should prevent this.

BTW, lean air-fuel mixtures does generate more NOx which results in higher than normal nitric acid during combustion. Given that taxi drivers have a bad habit of adjusting their LPG systems to running leaner than normal, I would not be surprised if taxi units encounter this problem more than privately owned cars.