Question On Spark Plug Boot

MiraOwner · May 25, 2011

hi Guys,

i examined a friend of mine's car the other day and found out that one of the spark plug boots is not the correct one installed for the model. 3 of them original and 1 from another car manufacturer altogether. and one more thing i observed is that the spark plug in this particular cylinder is brownish on the ceramic end where the boot connects to the plug. the car is having a lot of vibrations on the lower gear higher RPM (for example when climbing a hill) could this be the cause. and can this mismatch have an adverse effect on performance of the engine?

Thanks

Watchman · May 25, 2011

its brownish probably cos the boot isnt the right one and dirt and what not is going inside. Why dont you remove that plug, fix it to the wire ground it, start the engine and see if it still fires? If it does then the different boot and/or plug is probably not the issue.

The Don · May 25, 2011

hi Guys,

i examined a friend of mine's car the other day and found out that one of the spark plug boots is not the correct one installed for the model. 3 of them original and 1 from another car manufacturer altogether. and one more thing i observed is that the spark plug in this particular cylinder is brownish on the ceramic end where the boot connects to the plug. the car is having a lot of vibrations on the lower gear higher RPM (for example when climbing a hill) could this be the cause. and can this mismatch have an adverse effect on performance of the engine?

Thanks

What you describe could be caused by quite a few things, but like you say issues with the plugs (not being the correct type, needing replacement) plug wires etc can all contribute.

I would first take all the plugs out, clean them and put them back in and see if there is a difference.

If the car is not idling well, I will then take one plug wire out at a time and see if the car tries to stall (if the plug wire is working properly it should try to stall as you've just taken a cylinder out of action). If you notice no difference when one of the plug wires are taken out that plug, plug wire could be faulty. A good mechanic should be able to do all of that for you.

A plug wire mismatch shouldn't be an issue as long as the wires are all working and good quality. But the fact that a wire has failed and been replaced probably means its time to change the set of wires anyway. I recently did mine, but sadly was not satisfied with the quality of wires freely available in SL (a brand called SEIWA which set me back 4500 !) I would have liked to have used genuine NGK wires.