420A Spark plugs are black with white tip

[DrewmHolland]

This is one of my spark plugs after about 50 miles on my recently boosted 420a it’s running at 8psi and I can’t seem to figure out if my afr is any good based off of these plugs, I do have an adjustable fmu that I have been tweaking and this seems to be its happy place but I don’t know if it’s running right based off how the plugs look.

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[BLACK'98DSM]

Get yourself a wideband AFR gauge and no more guess work. 50 miles won't show much on the plugs. I see a rich burn, but that's objective at this point.

 

[DrewmHolland]

a wideband would be a good future investment but for now I just need to get my air fuel close to stoich, luckily the plugs show zero detonation currently, I found out that I was lean under full boost and rich at half throttle due to the placement of my fmu vaccum line. It now runs perfectly and I’m about to pull the plugs again and check for detonation. I’m at 35psi idle and 75psi fuel pressure under full boost on 24lb injectors

 

[Sirius1995]

https://www.dsmtuners.com/threads/help-for-diagnostics.545811/

 

[1990TSIAWDTALON]

If you are boosting a motor, you need a wideband to monitor your AFR's. You are shooting in the dark trying to guess at stoich.

 

[bo0st2]

If it was me I would've added the wideband before the turbo so you'd be ready for this