MOT - Hydrocarbons to High

[gw1]

My S3 has just failed it's MOT. The inspector said the Hyrocarbon's were to high ??

Possibly due to the engine miss firing or air getting into the system ??

The engine runs fine and didn't miss a beat all the way to garage.

Has anyone had this problem before or know a good garage near Oxford where I can get it sorted.

[ceejay73]

Hydro-carbons too high usually means unburnt fuel passing through the engine and out of the exhaust. Suggest you check, clean/replace spark plugs. Check, clean/replace distributer cap. Clean up ignition HT leads and check em for leaks, best way to do this is run car in the dark (ie in garage with the lights off but dont gas yourself)with the bonnet up and watch the leads, you are looking for them lighting up as the power for the spark runs away along the outside (if they light up like Blackpool illuminations this is a bad thing and they want replacing). Hope this helps and good luck.
Carl.

>> Edited by ceejay73 on Monday 9th May 18:48

[spitamenes]

hi
if the c.o. level is fine on idle then the tester is alowed to raise the engine revs to around 2000 rpm to see if the hc level will drop