Spark Plug Concerns - Help (1 Viewer)

[GrawDaddy]

Hi All,

I pulled my plugs and got the following results. From left to right are cylinders 1-6. Cylinder 1 is covered in some sort of debris (looks like ash) and cylinder 2 looks a little dark and oily. Cylinder 3-6 look OK. The two additional photos are both close-ups of Cylinder 1 plug. I'm wondering if anyone has any ideas what may have caused this issue though. I have been suspecting some ERG issues...

FYI 1993 FZJ80

 

[Bambusiero]

My #1 looks like this too.
The cause of it remains a mystery, although an expert has told me, along with a leakdown test, that it seems to be due to a stuck oil ring and the oil is getting burned off, leaving the ashy residue. Maybe.
He says just drive it.

 

[GrawDaddy]

Thanks Bambusiero! I swapped the plugs for some NKG’s and fired her up, very smooth now. I was having some bad misfires, not sure if it was from #1 or #4 (on reinspection I noticed the #4 gap was WAY too small). Maybe #1 was the problem, maybe #4, either way no misfires but there was a ton of condensation for about 20 minutes, like a smokestack! I wonder what this means... either way the truck runs pretty well now, but always looking for additional input. For now I’ll take Bambu’s advice and “Just drive it”.

 

[BILT4ME]

If you had tremendous amounts condensation or white smoke (like "clouds" of it after first starting) and went on for 4 or 5 minutes continuously, then you should also be concerned about head gasket failure starting.

What I see is a lot of ash on #1. This can be oil or anti-freeze causing this. Typically oil, but it's also running very hot in order for this to occur.

#2 is oily, as it's starting to foul due to either valve seals, or rings.

# 3, 4, 5, 6 all look pretty normal.

Since #1 and 2 are next to each other and since they both have their issues, they MAY be related. It COULD be a failing HG on cylinder #1 (second most common to #6) and it could be affecting #2 due to heat or the failure point.

There is also a possibility you have an injector failing and not supplying enough fuel, thus running VERY lean. This condition can melt a hole in a piston if left unchecked.

Usually, a failing HG tends to steam clean the plug and make them look brand new.

A few questions:

How many miles on it?
What oil are you using? (Brand and weight)
What antifreeze are you running (Brand and color)?

Check your engine oil and your coolant for signs of chocolate milkshake type look. If you have either in there, you have a serious problem.

Diagnosis suggestions:
1) Get a compression test done
2) Have an oil analysis done (Blackstone Labs or equal)
3) Have a exhaust gases test done on your radiator to confirm/deny exhaust gases in your coolant (indicating HG)

You may already know this, but the 93-97 are known for HG failures. It may be your turn.

Good Luck!

 

[Jgunner]

Time i had plugs like that, was a cracked head leaking coolant.