We are often asked to look at vehicles which have been elsewhere for diagnostics often unresolved but nearly always with many new parts fitted.
This VW Polo was no exception it had been to at least one other garage and came to us with a misfire on number three cylinder.
This particular Polo is the 1.2 petrol variant so a misfire leaves it severely under powered.
Initial consultation revealed new coil and plugs fitted with no improvement.
We carried out our normal diagnostic investigation which confirmed good ignition and engine compression so our attention was taken to the injectors.
Removal of the injectors and testing in our Asnu testing equipment soon revealed the cause of the misfire.
Number three injector was over fueling and had a leaky dribbling spray pattern. A new injector restored correct running with no misfire.
VW Polo 1.2 three cylinder engine..
Injector over fueling causing misfire
Poor dribbling spray pattern on number three injector causing misfire on test in our Asnu injector bench..