black soot on garage floor behind car

I get the same thing from my (Spica) Alfa. It's set on the rich side. (I couldn't convince my mechanic that it didn't need to be that rich. He felt that a 10.5:1 compression engine _had_ to be rich. And it takes a special tool to adjust mix on a Spica pump.)

In the case of a CIS car (512i), you might be looking at a leaking cold start valve, or an inop aux air valve, or the warm-up regulator pressures may be off.

On the other hand, that carbon may be left over in the exhaust, and may be from a couple of tune-ups ago.

 

My 308 does the same thing. I just think she likes to leave her mark where ever she goes.

 

it's normal.

Carbon builds up in the exhaust. When the car sits, condensation builds up and on warm up, the pressure of the exhaust blows the water out of the exhaust system along with with the water creating the effect you mentioned.

 

This guy is right on the money. Sounds like you guys baby you cars and need to go blow out the carbon. You should only worry if you see some silver flakes or rust colored flakes in it, that usually means your cats or your exhaust is about to gut itself

 

I get the same thing, the cold start cycle runs real rich, once tha car is warm it goes away.

 

My 400i (first photo) and 34 Ford with 425hp small block 351 Ford (second photo) both do the same thing. They both perform great. The Ford has 45K miles since I built it with the same plugs, etc. I can't imagine the 400i could run better than it does.
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I agree, i have noticed the same with my boxer but it only happens if the car has not been started for a few weeks, which with Irish weather is frequent, my Pantera is the same and it has a brand new engine, an easy way to determine f the car is unning too rich is to pull a couple of plugs
steve

 

Errrr.. Should we be concerned at all that you run your car with the garage doors down

 

Pantera, nice ride. I had a 72' edition at one point in my life. I just wish the US would bring them back in, some of the De Tomaso versions were awesome. I wouldn't mind picking up another one to compliment my 308.

 

Thanks m8, must say I love it, still so exciting and the sound is awesome
steve
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You guys with the soot marks must not be married. If I started the Lotus with the door closed, she'd scream about the smell and the noise!

Ken

 

Sweet toy. I am not sure what year yours is, but it definately looks allot newer than mine was. Its a beauty. Just curious, I know mine had a 351 Cleveland in it. What do they put in the newer models?

 

Its a 1987 GT5S, most of this type had 351 windsor but mine had a cleveland when i bought it, last year i sold the 351C and put a new 392 SVO stroker windsor in it, its now 450bhp and 460 lb/ft torque, suits the car well, everything else is original bar the dampers which are leda adjustables,
steve

 

I talked to my guy over at Norwoods in dallas texas area and he said the same thing. Said its soot from the exhaust and checked for leaks and there werent any. Gonna epoxy my garage in the next few weeks to mitigate the soot issues

 

The main products of internal combustion are water and carbon dioxide (for cars and people). On cold start of a car, the water vapor coming out of the cylinders which comes into contact with cold exhaust pipes condenses. The condensed water gets blown down and out the pipes bringing whatever soot it can carry. Once the exhaust pipes are warm the drip-stream and the steam seen disappear as the water vapor no longer condenses inside the exhaust line.

 

The cold start enrichment is also way too high considering how we baby these cars now: who is going to cold start a vintage v12 on a snowy day?

On my car the enrichment would rapidely decrease, but the initial few seconds where horrendous. I've increased the cold start control pressure and reduced the difference between hot and cold control pressure by 2/3. Takes a bit more time (20 seconds?) to "clear" the engine on a cold day, but it's much "cleaner".

Last but not least the cold start valves had to be matched against the thermo time switch and pulsing relay, and I am not sure this was always properly done during repair. My car came without the pulsing relay (that divides the flow by half), but was later serviced with a regular thermo time switch. This resulted in overly rich startups (to the point that my car would not start when hot!)

 

I keep small, rectangular, kitchen sized, plastic trash bins at the corners of the overhead doors to my shop. When it's time for starting after sitting for a week or better, I put the bins on their sides, behind the exhaust tips and then start the car. Saves a lot of clean-up time.

 

Parking the car the otherway round with the exhaust tips facing the door seems a good idea. Opening that door will also help...

I would reluctantly crank my engine in a closed environment.

 

why are you starting your cars with the doors closed
warning CO !!!!!!!!!!!!!!!