Plugs

[Cecil]

Hie Guys

I am 3 seriies fanatic i buy and restore 3 series i have a peculiar problem on a 1987 325i i have just finished restoring every time i put new plugs i hardly do 100km before the car starts misfiring and i have to change one or two spark plugs and it runs fine again i cant seem to find what could be causing this i have tried different makes of plugs but the same thing happens.

 

[epj3]

bad coil, bad ground strap, or really bad plug wires. Did you check to see if the threads in the block for the spark plugs is clean? If its covered in crap it wont fire.

 

[Cecil]

Coil is good HT cables are good grounding is Good no crap on the plugs like worn out rings kind just one or two plugs stop firing for no real reason and you have to stick in a new one have tried Champion NGK Bosch the works

 

[epj3]

Sounds like the plugs are getting seriously fouled. What color is the ceramic tip after the 100km?

 

[Cecil]

Light grey to Brown

 

[epj3]

Light grey to Brown

It shouldnt be your plugs then. I still think its your plug wires. Sounds like there is a bad connection that you temporarily fix when you shove the wire back onto a new plug.