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View Full Version : Running a little rich...

Billy Mild
12-14-2015, 05:58 PM
http://i856.photobucket.com/albums/ab123/billymild/zr1/IMG_20151207_161454_zpsddljpcz1.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.
A26B
12-15-2015, 12:54 AM
If that continues at startup, it may be an injector housing gasket leaking coolant into an adjacent cylinder.
Billy Mild
12-15-2015, 10:38 AM
If that continues at startup, it may be an injector housing gasket leaking coolant into an adjacent cylinder.

Not the answer I was expecting. Which injector housing gakset, housing to the head, or plenum to injector housing?
A26B
12-15-2015, 12:13 PM
To the cylinder head. The top side gasket of the injector housing is normally referred to as the plenum gasket.
A26B
12-15-2015, 12:29 PM
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.
RussMcB
12-15-2015, 12:49 PM
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.
A26B
12-15-2015, 12:59 PM
Probably silly thought: I wonder if someone could analyze that soot and tell its source (coolant/water, fuel
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.
XfireZ51
12-15-2015, 01:34 PM
The plugs could also look steam cleaned.
Paul Workman
12-15-2015, 02:44 PM
The plugs could also look steam cleaned.

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
Billy Mild
12-15-2015, 03:04 PM
http://i856.photobucket.com/albums/ab123/billymild/zr1/IMG_20151215_084458_zpsourmedsu.jpg

Another pic.

http://i856.photobucket.com/albums/ab123/billymild/zr1/IMG_20151215_084501_zpsjxbvtltt.jpg

http://i856.photobucket.com/albums/ab123/billymild/zr1/IMG_20151215_084504_zps3p1tq8kn.jpg
WARP TEN
12-16-2015, 01:13 PM
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

http://i856.photobucket.com/albums/ab123/billymild/zr1/IMG_20151215_084458_zpsourmedsu.jpg

Another pic.

http://i856.photobucket.com/albums/ab123/billymild/zr1/IMG_20151215_084501_zpsjxbvtltt.jpg

http://i856.photobucket.com/albums/ab123/billymild/zr1/IMG_20151215_084504_zps3p1tq8kn.jpg
Billy Mild
12-16-2015, 01:35 PM
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.