(i've searched)

I've got a Ported S4 13bt, and the plugs are always black and sometimes have a build up on them... Now i know that if they were wet, then it would be the engine is burning oil, but instead, they are just dry and black. The turbo is not pumping any oil as the intake tract is dry.

I figure this has somthing to do with timing since i am running a standalone (microtech). A/F is beautiful, running as lean as possible/safe under cruise and appropriatly rich under boost. The car doesnt see that much abuse, so im thinking that may contribute to the dirty plugs? Under cruise the car is running 30 degrees advance. What effect does timing play if any, on plugs?

 

which plugs leading or trailing or are they both the same. if the trailing are more black than the leading then the timing may be out a bit if they are the same you are most likely running to rich and need to lean out the mixture. does it have the same result if you push the motor hard and then pull them without letting it idle? if so then check the idle mixture pot on the passenger side of the engine bay just behind the air box attached to the front of the strut tower and turn it to R a little at a time till you get the desired result. ps the car runs about 10:1 at full throttle on the stock computer so you might wanna do a piggyback or a fuel computer/ pressure regulator if you wanna go getto but the computer will run at lean limit if you cant fix the O2 sensor voltage

 

interesting, whats the idle AFR?

stock ecu runs 30+ at cruise too....

what's the ignition system like? we ran 2 FC's years ago, and one was stock, and the plugs always looked great, the other was haltech/MSD dyno tuned and the plugs were black.

IMO i don't think the haltech does the dwell right on the stock coils....

 

Mafgar: Im running the stock plugs for a t2, but like i said above, i Have a microtech, so the stock computer stuff doesnt apply... I havent cleaned and rechecked after a hard run to see the plugs though.


j3fd3s: The idle AFR is around 13:1, Thats pretty much as lean as i can go and still get a smooth idle at like 800-1000rpm.
As far as the ignition system goes, I am just running the stock coils from an N/A (I assumed they were the same?) and a set of MSD wires. As far as the Dwell setting goes, its the factory setting from Microtech...I think 3.00?

The car runs amazing though...Pulls very hard the entire rpm range, no hesitations/misfires

 

No ideas? I thought it had to do with running premix (maybe too much) but then i went back to the OMP and same results.

 

lol, i was about to say, maybe its the premix....

i bet its the dwell then, but if it runs good, i wouldn't worry too much