Spark Plugs, Advance And Mixture Setting

[futura 3]

Hi, I am currently setting up my engine (1.9 8v) as it was running way too lean and I had to adjust the mixture screw on the AFM. I have set up the advance until it started pinking and retarded it back a bit.

I get the following colour on my spark plugs, in reality it looks actually more light grey/very light brown.

 

From the above pics and taking into account they look slightly darker in reality, does it look to you like the mixture is right, or should I set it a bit richer?

Your views would be much appreciated.

[lagonda 42]

Plugs in mine are a very light coffee colour, which I would say is about right. To me, yours indicate running too weak. Be interesting to see what others say, as I was going to post about setting mixture by spark plug colour but never got around to it!

If the concensus is that yours is running weak, reset your ignition timing afterwards as weak mixture will exacerbate pinking.

[futura 3]

Thanks for the reply lagonda. I have been told elsewhere too that it's running a little too lean

[futura 3]

After playing with the mixture adjustment screw and test driving the car several times, I still can't get a decent colour on the spark plugs, and the mixture screw is screwed in to the maximum.

Does it mean the AFM is out of order? What should I do next?

[hengti 2]

maybe consider retracking the AFM. i think there's a guide on the main site

 

realistically, the only way you're going to be sure it's set up properly is to take it to a rolling road

[futura 3]

The AFM has already been retracked I am thinking its sensor must be knackered?

[DamirGTI 342]

Hi !

 

Maybee this helps - list of spark plug conditions :

 

 

Cheers

Damir

[James_m 0]

Pretty sure the mixture screw on the AFM will only control the idle mixture.

[hengti 2]

is it actually running lean? are you only going by plug colour?

 

those plugs look OK to me, if a little light (were they photographed shortly after having been fitted new?)

 

has it been connected to a CO meter?

.

the allen key screw doesn't do much (as mentioned above) - you'll need to recalibrate the AFM to make much of a difference to the A/F mixture as i understand it

[futura 3]

Thanks for the replies. I actually had doubts on the mixture screw effects as I hear two stories.

 

The emissions were checked a year ago with this AFM and were ok, but I had the injectors refurbished since then and the mixture needed adjusted accordingly.

 

I guess a professional setup is required now.