Had some rattling from the cat, started on Tuesday. I had noticed that the car seemed pretty 'pokey' when it was cold then kind of felt restrained when it started to warm up - also a tell tale lumping idle (not hunting, just lumping). Thought logical that if the cat had started to break up, it could end of blocking the exhaust and that could lead to the car acting up.
Today the new type approved cat turned up, started pulling the old one off - the front O2 sensor looks almost melted, the metal surrounding the inner ceramic has melted in totality and is welded onto the ceramic however running it under diagnostic, its still functioning in spec 🙂
New cat fitted with new gaskets blah blah - took it for a gentle 10 mile run as advised in the papers that came with it and hell yea, already a nice difference, more responsive and torquey. The rear sensor is in great condition and I will buy a new front sensor tomorrow. On inspection of the cat, the rear still seems intact however the front of the cat is full of 'stuff'.
Questions:
- When running pre change diagnostic, saw that the short term fuel trim was negative indicating running lean - is ECU running lean symptomatic of a blocked exhaust
- Is melted O2 sensor symptomatic of blocked exhaust?
- What would have been the repercussion of running the car with a blocked cat?
Another job sorted - no more please, I'm broke :lol: