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Strange Exhaust Emissions

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Hi,
My 951 emits strange black dots of something, worst when just started up. Could this be bits of the inside of the Cat? The exhaust is intact but presumably quite old as the car only gets limited summer use. The car doesn't use oil (I have recently rebuilt the entire engine) but does smell badly of petrol, especially when used a little "enthusiastically". May not be connected but any info would be appreciated.
Thanks.
 
Speaking from my experience on a non turbo, non cat car I would say this is quite normal. Mine will make a mess of anything parked within a few feet of the tailpipe when it's cold. I guess it's condensation mixed with soot. Great for getting revenge on numpties who park too close :ROFLMAO:

If its getting worse then it's worth having it checked, but if not I'd say don't worry.
 
sounds ike its running rich to me ? hows your petrol consumption ? might pay to check your plugs for colour
 
Yea, I wondered about running rich. I am using Promax level 1 chips and adjustable boost controller etc, but the plug colour seems fine. The little adjuster on the DME (or maybe it's the KLR) is set at lean, so I don't know. I think I will get it to the rolling road and have it checked. Fuel consumption seems to be about 22 - 24mpg regardless of road type. I think this is OK for town but seems a bit poor for motorway driving.
 
I've been using my car every day for the past few weeks and she is despirately in need of a wash and her rear end is peppered with the black spots you mention. I got them before I fitted my Promax chips so it is not something that is aftermarket chip specific. It will simply be black soot deposits - I don't think there were many lean burn engines around in the '80's.

I did notice a drop in fuel economy with my Promax chips to the tune of around 25 miles per tank so they definately do run richer than stock.
 
Also useful comments, thanks.
I suspect I'm so used to modern engines that something like this seems a bit alarming at first glance. I have no problems with the rebuilt engine other than this, and to be honest the old engine could have been the same without me realising. It's strange how you notice every detail when you've built your first engine and are just waiting for something to go wrong, but I guess I should have more faith!! Its done nearly 5000 miles now including a trip to Berlin so if it was going to break it probably would have by now.
Again, thanks everyone.
 
Engines get more sooty when used for shorter runs.

When did it last get a good hot run on a motorway? (Going to Berlin sounds ideal for this! How long ago was the trip?)


Oli.
 
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