Running a little rich...
 

http://i856.photobucket.com/albums/a...psddljpcz1.jpg

Those black spots are coming from the ZR-1 when it is started up cold. I have also noticed it smells a bit rich too. The car still has cats, Borla axle back and deleted center resonator.

I have heard it has a custom tune, but he chip appears to be stock.

Re: Running a little rich...
 

If that continues at startup, it may be an injector housing gasket leaking coolant into an adjacent cylinder.

Re: Running a little rich...
 

Not the answer I was expecting. Which injector housing gakset, housing to the head, or plenum to injector housing?

Re: Running a little rich...
 

To the cylinder head. The top side gasket of the injector housing is normally referred to as the plenum gasket.

Re: Running a little rich...
 

Afterthought: if the injector housing gasket is the source of a coolant leak, it will be into any of the front 2 cylinders on each bank, i.e., cylinders 1&3, 2&4.
A quick & simpler check would be performed on a cold engine after full warm up. Remover the plugs on the cylinders mentioned, pull the fuel pump fuses( both primary & secondary). Have someone crank the engine over & look for coolant blowing out of a cylinder. It won't be continuous, just a quick puff.

Re: Running a little rich...
 

Probably silly thought: I wonder if someone could analyze that soot and tell its source (coolant/water, fuel, ...)

Maybe looking at the plugs would provide more clues, especially if 1 or 2 look odd while the others look good.

Re: Running a little rich...
 

Sure, get some on your finger & stick it on your tongue. Sweet - coolant if anti freeze present, fuel-you will know, nasty.

I could never see it on the plugs because the amount was small and it only appeared in the exhaust at cold startup.

Re: Running a little rich...
 

The plugs could also look steam cleaned.

Re: Running a little rich...
 

Yeah! Nothing like coolant blowing a hole through a thin (ported) spot in the injector housing to steam clean the entire top-end!! (ask me how I know...):p

Re: Running a little rich...
 

http://i856.photobucket.com/albums/a...psourmedsu.jpg

Another pic.

http://i856.photobucket.com/albums/a...psjxbvtltt.jpg

http://i856.photobucket.com/albums/a...ps3p1tq8kn.jpg

Re: Running a little rich...
 

Is it possible that this is just a lot of condensation in the mufflers spitting out with normal soot in the exhaust system on start up? When you drive the car does it show black exhaust smoke on acceleration? Once it warms up a while (and the condensation is evaporated) does this condition go away? Our mufflers can pick up a lot of condensation and if the little drain holes in the mufflers are blocked it will sit there until you start and run it. Usually blows some water vapor for a while as it warms up. Just curious. --Bob

Re: Running a little rich...
 

No black smoke when driving or any smoke at all. It appears to be water.

My previous car when a similar condition would show up, along with running rich it was a failed FPR.