New motor idling little rich

[MSDGN]

I have a new motor I'm breaking in...109 block with 214/210 billet roller...JE's...GN1's(race ported)...72lb injectors...it's running great except that it is idling a little rich...no black smoke...just smells a little rich...I checked a couple of plugs after about 25 miles and they have little black coloring...oil is good so it's not washing the cyls...BLM's were initially at 140(idle) so I modded that by lowering the BLM(by 8) via Trans+ and the Extreme Extender chip which got it to 132...still smells little rich...the FP is set at the recommended 45 PSI (line off)...not sure what to try next...it is just the nature of the bigger cam that it will run richer at idle?...I can lower the BLM another 4 to get it to 128...any ideas...

 

[bruce]

I can link you to a dozen threads where folks are talking about cars smelling rich. I'm just wondering if it's some new Formulation of gas, that's at fault.

While not bad, mine even at times, has a small *scent* to it. And I've spent a fair amount of time optimizing the idle timing, and AFR.

One thing, is if you used some non friendly O2 sensor chemical in the assembly, you might be having an O2 die/ get lazy.

 

[MSDGN]

I'm running 91 octane now but was previously running pure 116 octane on the same O2 sensor...it is a heated one and the crosscounts/numbers looked good but I suppose it could be on it's way out...won't hurt to try a new one...

 

[Quick6'n'-K.C.]

Vacuum leak could cause the blm to rise right?

BW