One strange spark plug colour?

**Stav** · 11-06-2007, 10:05 PM

if anyone has ideas on what this may be please comment.All of my spark plugs are like the dark one on top of the photo but cylinder number one is much lighter.What can be causing this? I have already changed the plug and it came up the same. Is it a coolant leak?Is it a leanout in that cylinder?

Fairlane · 11-06-2007, 10:34 PM

Checked the backpage of my Haynes manual and its pretty tricky to diagnose, looks like High Speed Glazing which makes no sense at all, they are all the same plus and at the same temp.

Has it done this to the no1 cylinder before?

If not im thinking it may just have been a faulty plus (ive had brand new plus not work at all for me) or at a guess maybe incorrect gapping. I probably being a smart ****, but the gap on the faulty one does seem quite a bit less than the good plus.

**Stav** · 11-06-2007, 10:50 PM

It is the second plug in that cylinder today to go that colour? It is almost like there is some residue being pushed in from the fuel inlet and getting stuck in that injector..its wierd?

bodes-sh · 12-06-2007, 08:13 AM

from those pictures the one at the bottom, the lighter one, looks like it is working normally, ie normal heat range, but the other one looks like it has carbon or oil buildup on it...

FS5 · 12-06-2007, 03:59 PM

Quote:

Originally Posted by bodes-sh

from those pictures the one at the bottom, the lighter one, looks like it is working normally, ie normal heat range, but the other one looks like it has carbon or oil buildup on it...

i'd agree with that ,all my plugs look like the one in the bottom of the pic .

its strange how its only doing it on the one cylinder though .

going by the pic it looks like the one on tops been running a bit rich.

stav ,you sure you ment the bottom plug in the pic is the one thats a different colour to the rest .

**Stav** · 12-06-2007, 08:16 PM

All my plugs looked like the top one.The odd one out was the bottom one.At this stage after running 12 volts a carbie cleaner through it so far it is running like the rest.I might pull all of them out and run cleaner through them again as this intermittent misfire is very confusing!! I will install a fuel gauge in it tommorow night to maybe sort the issue.

fritzz · 12-06-2007, 08:29 PM

if they are all like the top 1 then theres a problem, the bottom 1 looks good.

its either to much fuel, not enough spark(stuffed plugs) or even oil. u would be able to tell if its oil coz it will have a bit of a shine.

how old are the spark plugs?

**Stav** · 12-06-2007, 08:32 PM

I on puposely ranthe car irch via my adjustable regulator for fear of blowing the engine up.If it is a lean misfire the last thing I want is for it to detonate.Hence the darker colour .Today I ran it a bit leaner and the plugs look clean.

GSN · 12-06-2007, 10:31 PM

bottom one looks good. Stoichiometric ratio burns a light browney reddish tingy colour. that how we used to check a/f ratio in the carby days

Crash Lander · 12-06-2007, 10:58 PM

I was also going to say that the bottom one looks the way they all should look.
Does the car blow any smoke at all?

**Stav** · 12-06-2007, 11:00 PM

Quote:

Originally Posted by Crash Lander

I was also going to say that the bottom one looks the way they all should look.
Does the car blow any smoke at all?

No smoke at all.

FS5 · 13-06-2007, 02:42 PM

maybe the injector on that plugs faulty or dirty or something and its running lean compared to the rest.

mr_xr8 · 13-06-2007, 02:58 PM

get the injectors flow tested and take note of which cyclinder they came out off.

**Stav** · 13-06-2007, 07:34 PM

I think I fixed the spluttering issue.I totally disconnected the ego sensor and the car did not splutter or do anything of the sort all day..I think I found the issue.number 1 spark plug again was slightly whiter than the rest though.It may be my porting isnt exact or air leak..or..crap injector..