black spark plugs..

[olly]

went over to my friends place today to have a look at his car.. it's not a mitsubishi but it wouldn't matter anyway..

problem is we put in fresh sparkplugs a couple of days ago and we pulled them out today and one of them were black.. running rich?

he recently got it tuned at protek (got a powerfc), but they said his injector in cyclinder 3 was running at 95% only.. his gettin a compression test done to it to see whats up but anyone else know what could be up? maybe injectors or something rather?.. his motor also shakes alot, but idles fine..

 

[SIVART]

This is happening to me also

Im thinking running way to rich on idle

if I drive the car for along distance its ok but short trip and it fouls the plugs

 

[JSTYLE]

what sort of plugs is he using? what rating are the plugs? ie.. BP7ES or BP8ES etc..

has he had the injectors cleaned recently? Id reccomend that injectors be pulled off the car and taken to an EFI specialist who normally charges about $120 to clean all 4 injectors..

Jon

 

[maccavr4]

could be oil fouling caused by oil ;passing through the rings just a thought

 

[olly]

yeah when he got it tuned, they pulled out the injectors and cleaned them.. so i guess they were all working? unless they didnt test them?..

 

[olly]

ok found out the source..
the injectors were clean/flow tested but it didn't show that injector in #3 cylinder wasn't closing properly. So when he turned off his car, the injector would leak into the cylinder causing the spark plug to get wet/hard to start up.. comp test showed 140 140 120 140..
still doesn't explain the shaking of the motor..

 

[maccavr4]

the 120 could be a issue in the future though

 

[doommachine]

I was using a rexona can filled with steel wool as a muffler plug for a while.. and I am 95 % sure that is why my car wouldn't start for ages... basically the restriction in the exhaust, coupled with running rich, seemed to foul the plugs, because I had the plugs out prior to screwing with the exhaust, and they were fine, but when I pulled them out and replaced them.. they were black as black can be.. carbon was caked on them.

Sorry, what I am trying to suggest is, perhaps there is some kind of blockage or problem with the valves in that cylinder? That would explain the shaking, as the cylinder wouldn't be firing properly/ the same as the others.

 

[Richard]

shaking is mostly caused by a problem with engine mounts check they are not flogged out. if good maybe not centralised, need to loosen every thing run motor a bit and then tighten it all up usually works.