Wot can cause this

[TechtroT25]

Theres a camper up for sale near me that has failed the mot on the following "Exhaust emsissions hydrocarbon content excessive" now the seller reckons its a valve problem but any ideas if owt else can cause it and how can i tell if it is a valve oh and its a 1.9 petrol cheers Stef

[jamesc76]

This from a Yank site but explains a lot mate :

http://www.autoshop101.com/forms/h56.pdf

[VWCamperfan]

A compression test would reveal more about whats happening inside the engine and give you a few clues.
Most emission failures are related to fueling issues however and are usualy caused by a poorly maintained/adjusted carb or airleaks between carb and engine.

[TechtroT25]

Cheers for that Jim is their any tell tale signs ie smoke ,smells rattles etc

[jamesc76]

You thinking of buying it ???? Service it give it a good thrash to MoT and dont put air filter in till after usually works!

[dugcati]

also wind the mixture screw back a bit too

[TechtroT25]

You thinking of buying it ???? Service it give it a good thrash to MoT and dont put air filter in till after usually works!

Yeh thinkin of it just gotta see how much he wants for as its on ebay £750 starting and he has a reserve on it seems a bit rich for summit that may need a new engine/rebuild but we shall see looks like a straight van though heres the listing number have a shuffty 120466207073

[Aidan]

check the vacuum take off pipe for the servo these go porous over time so that side runs lean, you turn up the mix to get correct co but hc now high cos other side running rich, use carb cleaner to check for inlet leaks