what would cause a black sooty discharge from the exhaust and an acrid smell. The car is otherwise driving well and is not showing any problems on the dashboard display. The car is a golf estate.
Country: United KingdomMake: volkswagenModel: golf estate
an annual service with my local garage which found the emissions were higher than they should be
Is the engine light on?
no no warning lights on dashboard
Relist: Other.i have not received any help at all yet. i have paid 20 pounds for nothing so far
I'm am so sorry for the delays there were site issues and internet issues . The most common issues are dirty fuel injectors or a faulty mass air flow sensor were these checked ?
Relist: OtherWe still need help and are being asked for extra info please be very precise as to what info is needed - there really is nothing showing. Engine runs smoothly, however there is an acrid smell when car has been driven which increases in intensity if fans are used in car (obvious I suspect) gas emmissions were high at MOT but were reduced by garage to pass MOT. Smell has returned suggesting emmissions higher again and sooty deposits are left on drive after car is used. No engine management lights showing and we are now using the cleanest unleaded fuel. If you need anymore info please detail.
HelloOk if the engine is running rich to extent of leaving soot marks on the drive then I'd 1st suggest getting the fuel pressure checked as if this is high due to a faulty regulator this can result in over fuellingI'd also check for exhaust leaks before the O2 sensor as if this has been experiencing an exhaust leak then it will have been running very rich as the sensor will see the extra air pulled in as fresh / lean fuelling and be adding fuel to compensate.this can lead to catalyst failure as the extra fuel can re-light inside and melt the catalystThe best way to find an exhaust leak is to run the engine from cold and feel around the exhaust joints with your bare hands - you'll have about 30 seconds before it all gets too hot and you should feel any escaping gas blowing over your fingers Also replace the spark plugs if any of them fail this checklist:http://www.ngksparkplugs.com/tech_support/spark_plugs/faqs/faqread.asp
Mechanical Engineer with 20 years experience in the auto industry, 8 yrs in formula 1 engine testing
thank you for getting back to me. when the car was serviced they found a small crack in the exhaust pipe which they fixed so will check the fuel pressure and the spark plugs and go from there.
Helloif the crack in the exhaust was before the oxygen / lambda sensor then its quite possible that this was the issuelet me know if I can help further