7 replies to this topic

[widg]

Ok my 1275 mini failed it's MOT today on exhaust emissions hydrocarbon content excessive, any suggestions on how to solve it ??

[patricksouth]

How excessive,is it injection or carb

[widg]

Carb max is 1200 mine failed 1570 is that a lot ??

[FlyingScot]

Moved to non fuel injection section, for better answers

FS

[Stiggytoo]

Check valve clearances, lean off carb, do a quick service if this is due. Maybe ask to go in during the mot as I don't think the tester is allowed to do anything to your car. They will probably be happy to let you tweak the mixture further if the hydrocarbons are still over 1200.

[pickuptruck1994]

If the co is fine it has got hasnt got anything to do with the carb hc are un burnt fuel so look at plugs dissy and leads. I have this, changed plugs dissy cap and arm and came down to about 200 hc

[KernowCooper]

HC readings on the high side can be caused by incorrect ignition timing, poor ignition components like plugs and a engine thats weak on compression. You can also have a High HC reading due to a very weak mixture or a air leak where incomplete combustion takes place.

[A-Cell]

Increase the tick over(idle speed) to 1800 rpm and re-test.
Better still ask the test station to let you keep increasing the idle speed until it passes i.e. sit in car and use throttle pedal.