Just bought some better spark plugs and upon changing them have noticed that they are ranging from dark to light in sequence

#1 being the darkest
#4 being lightest





is it running lean? im still running it in, will be getting set up once running in is complete

what would cause this and what can i do to alleviate the problem if it is for the time being? will i still be ok to use it like this til i get it set up in a week or 2?

 

3 look ok to me, one looks to be running richer than the others.

i'd think about having your injectors flow tested before mapping

 

just got a price from local bosch place to get them cleaned and flow checked think ill have to get em done

 

Number four DOES run leaner and hotter that the other three.
Number one richest coldest, progressing to number four hottest and leanest.
This caused by the designof the cooling system mainly and the way the water circulates around number four last after it has picked up heat from the other three.
Your plugs look fine, but by all means have the injectors cleaned tested, it won't hurt.
tabetha

 

what did they quote?!

Phil does it at nice price. Whenever you post them he gets the next day, tests immediately and you get them back the next day. excellent service

 

i can get them done for £12 an injector plus ill get them done the same day which is better for me as the car gets used daily

 

What was the problem with your engine in the end? I tried to find the post unsuccesfully.

 

little ends were worn quite badly which caused lots of piston to bore movement due to the hole in the piston where the gudgeon pin goes through had gone egg shaped

 

How did you resolve. New rods and pistons?

 

new pistons and little end bushes

the rods were ok

 

Ah cool. Glad its almost sorted. Sorry for the questions but a friend has similar symptons and we are thinking we have a similar issue to what yours had.

 

plug colours tell you almost nothing about the mixture...

Alex

 

i agree

 

What they DO tell you is how hot the plug is running - the colder the plug the more black it will appear and the oppisite for a hot plug.

Having said that all 4 plugs should be the same colour....

Alex

 

Plug will tell you mix IF it is the correct heat range.
Look in ENGINE MANAGEMENT, by DAVE WALKER, clear descriptions there.
tabetha

 

arent you running it on standard yellows/dark blues????

just i thought your car was greys/t4 etc?

 

Thats a big word, i guess sarah was typing

How much more running in you got mate?

Bri.

 

Tab, if you read it pages 14,15,&16, dave quotes that plug colour has nothing to do with mixture condition, what you are in fact is looking at temp of the plug, as indicated by the colour of the carbon, if you fit a hotter running plug the colour of the carbon will be a lighter shade, this does not indicate a weak mixture, just a hotter running plug,
he goes onto say tuning by plug colour, the colour indicates plug temperature Not Mixture Ratio. and if you fit a colder running plug the carbon will be darker even sooty in appearance, its not rich just colder running, i think most people get side tracked by plug description as in haynes manuals.
Although it does contradict in that say you had a vacuum leak, and the temp increased in the cylinder the plug would change colour and the mixture AFR also? .i think dave w is assuming the engine state of tune is all good.
Regards Dave R.