Cupra 300 over fueling

[Beef46]

Bit of an update. Car went back to the dealer and it looks like they may have found something. They checked the oxygen sensors and I think they said they pre-cat sensor was asking for 5% fuel and the post cat sensor was always asking for 100% fuel!

It's going back in a couple of weeks to have the sensors replaced. Fingers crossed that cures it.
I will update again once this has been done.

 

[RUM4MO]

That sounds strange as the pre cat probe is part of the fuelling control system and the post cat probe is just a monitor probe so it should not have any influence on the fuelling level - only warning for emissions being out of allowed levels.

Edit:- hopefully you have just picked them up wrong and it is the pre car probe that is forcing this over fuelling.

 

[Beef46]

That sounds strange as the pre cat probe is part of the fuelling control system and the post cat probe is just a monitor probe so it should not have any influence on the fuelling level - only warning for emissions being out of allowed levels.

Edit:- hopefully you have just picked them up wrong and it is the pre car probe that is forcing this over fuelling.

Yeah fingers crossed. I cant remember exactly which sensor they said was doing what, just that one was asking for 5% and one for 100%.

 

[mty12345]

Yeah fingers crossed. I cant remember exactly which sensor they said was doing what, just that one was asking for 5% and one for 100%.

Sounds like nonsense, only one sensor has anything to do with fuelling, as said, the second one just monitors the efficiency of the cat.

 

[Beef46]

Sounds like nonsense, only one sensor has anything to do with fuelling, as said, the second one just monitors the efficiency of the cat.

Well if it is then we'll find out soon enough and they'll have to scratch their heads some more.

 

[mty12345]

Well if it is then we'll find out soon enough and they'll have to scratch their heads some more.

In my experience a lot of dealers/garages don't have a clue when it comes to diagnostics. If it doesn't give them a fault code or it isn't covered by one of their flow charts, they'll just start throwing random parts at it and hoping it fixes it. Sounds like that's what is gonna happen here, but if they're paying then fair enough. If you were paying it'd say take it somewhere else.
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