How do the plugs look to you?

[willworkfore30s]

I changed the spark plugs in my m42 yesterday for the first time since I've had it. Its been running for me a year now. Before the new plugs the car would sputter some and didn't accelerate completely smooth all of the time. The new plugs cleaned all of that up and the car feels really good and strong now. I know that I should have changed these a LONG time ago but just now got around to it.

Anyway. My question is how do my old plugs look. I don't know much about reading plugs but I know I have seen people diagnose whether a car is running rich or lean from looking at the electrodes. These may very well be the original plugs for all I know. The car seems to run fine to me so this is mostly out of curiosity. Maybe you guys can teach me something about reading plugs.

Thanks in advance.

#4(Back of the engine)


#3


#2


#1(front of engine)

[bmwm42]

Those look like shit......your leaking oil in the chambers

[Dj Buttchug]

very hot fire. possible lean condition

Edit. guaranteed lean condition.

[willworkfore30s]

Those look like shit......your leaking oil in the chambers

So what does that mean, worn valve guides and seals?

very hot fire. possible lean condition

What could be causing this?

The plugs could be 22 years old if that makes a difference

[Dj Buttchug]

those plugs are dry as the fuckin gobe desert. leaking oil is unlikely. the plugs dont show any residue oil related it seems. A lean condition could be caused by a number of things. weak fuel pump causing low fuel pressure. Un metered air leaks can also cause lean conditions. keep in mind shitty fuel can also cause plugs to look like that after a while.

Start by throwing the new plugs in and driving it around for a few hundred miles. then pull the plugs again and see what they look like. then go from there.

[willworkfore30s]

Good idea. I've run nothing but premium in it since I installed the motor. I think its 91-93 octane around here. I'll run her for 3 weeks (odo still doesn't work after replacing gears) and report back with how they look then.

[bmwm42]

Um sticking to my guns and oil is seeping otherwise why so much deposites unless your adding fuel addictives

[willworkfore30s]

I can't speak to what the PO did with the motor. Its got about 150k on it reportedly. I have put probably 2-3k miles on it with premium, no additives, 10w40 castrol gtx i believe

[roguetoaster]

Looks to me like deposits from nonburnable additives (fuel or otherwise). New plugs and time will tell.

[jntar]

Change them and check them in 10k miles. They look like both things said (excess oil, lean condition) could be possibilities. Checking a new set after 10k will better diagnose.

[TobyB]

they look very very worn out.

ANd they have stuff on them. Like, 150k worth of stuff!

On the up side, you're not pinging- that would have blown the stuff off!

heh

t

[mr ilia]

All this above is true ONLY if the plugs in question are correct heat rage...e.g. Proper to M42.

[roguetoaster]

All this above is true ONLY if the plugs in question are correct heat rage...e.g. Proper to M42.

Bingo! Why did we all forget that?