Age old problem, cant get on the kit car until the wifes car is fixed. Golf 1.4 16v 1989 took it for an MOT on Saturday and it flew through apart from the emissions, hydro carbons were high and carbon monoxide. I just thought it was overdue an oil and filter change. put new oil in and filter on it and took it for a retest today failed again. Other than plugging it in to a computer can any one give me any clues as it will be Saturday next before I can get to look at it.

fcuked air flow sensor? A problem on certain Golf's having seen the issue's my previous neighbour had with hers

Not sure, I make a 1989 to be a mk2? in which case I think its carb'd, if so its probably a pierburg (2e2?) carb with an autochoke, these go wrong as they have a very sensitive spring steel piece in side and after years/miles of pressure they fail. I would have thought that would make it difficult to start and have a fast idle though.....

As Tom's said - No 1.4 16v's in 1989 so I think you mean 1999, as in MK4?

I'd say if it IS 1999 and a MK4 it would be either a lambda sensor or a CAT.

Again - if it's MK4 you can use VAGCOM to help you trace the fault a little. Any decent garage will have the kit or indeed it can be bought for very little money yourself for a EBay OBD2 reader/resetter.

If it is Mk2 - As Tom's said the carb. Pierburg was dreadful and the auto-choke awful. Most converted to a manual choke.

When were the air filter/s last changed? If they are blocked it could cause high HC and CO levels.

Cheaper than an new cat/lambda.

[Edited on 17/3/10 by DorsetStrider]

yes, it is a 99 model. Airflow sensor makes sense will have to plug it in to be 100% certain just fishing around for a few hints, looked at changing the air filter but it was as new also the breather was not blocked going up to it (which can often be full of sick). Normally when you post on her people know straight away. Thanks for the suggestions.

is the coolant temperature sensor working? This was a common fault on vw/audi's at this time. If it is faulty it's possible that the ECU thinks the engines cold when actually it's hot... because the ecu thinks the engines cold it lengthens the injector pulse to feed more fuel into the engine which in turn would cause a high HC level.

Agree with the coolant temperature sensor