Spark Plug

[kspchew]

Can our Latio take other type of spark plug?

I am intending to change mine set (now at 45k km) as my Latio is CNGed and experiencing intermittent jerking.

Thanks

[Jazz]

Ours is using iridium spark plug and able to last for 100,000 km wor. 

[kspchew]

Yup, I know that but ours have a spark gap of 1.1mm and I need to reduce to 0.9mm

[aerosignal]

Yup, I know that but ours have a spark gap of 1.1mm and I need to reduce to 0.9mm

Reduce spark gap? Just take out the spark plug and bend it a little. Hope you have feelers though.

[kspchew]

The problem I faced is that I need to remove the entire manifold to gain access to the spark plug. So I am intending to get AS to change the plug for me during my 50k servicing.

  seems like latio spark plugs are too special, can seems to use other types

[aerosignal]

The problem I faced is that I need to remove the entire manifold to gain access to the spark plug. So I am intending to get AS to change the plug for me during my 50k servicing.

  seems like latio spark plugs are too special, can seems to use other types

Yup, can only use the Denso iridium plugs. Even the size is quite special. I am trying to finding the spark plug socket and the size is apparently more for motorcycles and ATVs. Not easy to find. Because it is small diameter and thin wall.

[Jazz]

Why wanna reduce the gap ? Better ignition or anything contribute to FC ?

[kspchew]

Why wanna reduce the gap ? Better ignition or anything contribute to FC ?

I am running on CNG, reducing the gap will have a better ignition and hence smoother ride. currently experiencing intermittent jerking.

[aerosignal]

Er, why do you suspect the spark gap is too big?
My advise is bring your car to the CNG installer and ask them to troubleshoot.
Intermittent jerking can be caused by several factors.
Reducing spark gap only works if a lack of spark is causing the problem. Unless your spark plugs are really worn, this should not be a problem.
If it is no ignition, (got spark but fuel don't burn) then the spark gap is too small. In this case, increasing the spark gap will be better (longer spark). I don't think this is the problem because CNG has lower ignition point (easier to burn).
If the intermittent jerk is when going uphill, then there is also the possibility of a loose spark plug connection.

Unfortunately, I don't know enough about the CNG system installed here to help any further. Advise is still to go to the installer.

[Xmen]

An additional ECU was installed for CNG system. It is normally located next to the battery terminal. The installer need to put in the right settings for your make and model. You need to seek the installer advise to fine tune if your car is fitted with other mod.

[kspchew]

Er, why do you suspect the spark gap is too big?
My advise is bring your car to the CNG installer and ask them to troubleshoot.
Intermittent jerking can be caused by several factors.
Reducing spark gap only works if a lack of spark is causing the problem. Unless your spark plugs are really worn, this should not be a problem.
If it is no ignition, (got spark but fuel don't burn) then the spark gap is too small. In this case, increasing the spark gap will be better (longer spark). I don't think this is the problem because CNG has lower ignition point (easier to burn).
If the intermittent jerk is when going uphill, then there is also the possibility of a loose spark plug connection.


Thanks for the reply.

I had been to the installer for the 10th time in 4month and still not resolve yet. FYI, CNG has a higher ignition point then petrol, hence an optimum ignition system is desired.

But I am not sure if my ignition system are optimal as my Latio is coming 3 years old this Sun 

The intermittent jerking only occur when accelerating from abt 60-70km/l after lifting the foot from the accelerator. Other than that, it's fine.
Unfortunately, I don't know enough about the CNG system installed here to help any further. Advise is still to go to the installer.

[kspchew]

An additional ECU was installed for CNG system. It is normally located next to the battery terminal. The installer need to put in the right settings for your make and model. You need to seek the installer advise to fine tune if your car is fitted with other mod.

Thanks though.

Yup, I have been to the installer for tuning (10times over 4 mths). I had read from SGCNG forum that CNG system is extremly seneitive to poor ignition system and those forummers advice me to change the spark plug gap to 0.9mm to 1.0mm and check on the health of the ignition coil.

Our latio is a coil in plug ignition system which suppose to deliver very good spark but to access that it is very troublesome, need to remove the entire manifold.  Sigh... seems like my Ah Bai Latio, dont like CNG

[aerosignal]

Ok.... Didn't know about the ignition point one until today. Always thought CNG burns more readily. Thanks for the info.