Hi Guys

I have noticed last few months i had to replace spark plug regularly than earlier i can run aground 3 or 4 months with a spark plug after that i need to replace at-least one spark plug , what would be the possible reasons for this,

My Ignition coil is new replaced last month

Is NGK or Denso is better ?

thanks
Regards
sumith

Normally spark plugs last a number of years. They only need gapping once a year.

You do you replace the spark plug? What evidence do you have that it is bad? There are many reasons, what was yours?

NGK and Denso are better. Champion and Bosch are good too.

Hi DD

Most of the time i have engine miss that time

Actualy I keep the car start and remove one plug wire by wire an if the engine doesn' respond to the removel i guess the plug is not working.
then after replacing it car running properly,

thanks
Regards
sumith

Are you sure it is the plug or is it a bad plug lead?
Make sure the leads are firmly pushed onto the plugs and there is no moisture anywhere in the connections to dissy cap or plugs.
Check the resistance of the leads, if they are all the same approx length, they should have roughly the same resistance.

Often the spark plug can be cleaned. Next time, carefully inspect the suspect plug. Is the gap still correct? Is it dry-black, or oily-black? Is it cracked?

This will tell us what the problem is.

Hi DD

Actualy Yesterday i had a problem with Cylinder 4 Spark Plug, i removed it it was dark black, that was clear brown color last week , so i cleaned it and installed again, it was still giving a engine miss but after some time it was ok,today i will go and check that plug again and tell you how is it ?

hi ssskiwi

actauly i checked spark plug wires last month they all were closed by similer resistence


thanks
Regards
sumith

Was it dark oily black or dark dry black? Look for that nice time.

I would perform wet & dry compression tests now.

Hi DD

It was dark dry black

thanks
Regards
sumith

Is it running vry rich, blowing black smoke and using a lot of fuel?

Could be fouling plugs from too much fuel? Would then be random which plug (cylinder) it is, if it is from oil contamination, it will be the same plug (cylinder) every time.

make sure the choke is not staying on and that the carb is in good condition.

Yes, that indicates it is now the time to perform wet & dry compression tests.