Renault Clio RS 182
I've just ordered another O2 sensor... this is the third one that the car's had in under a 1,000 miles of driving 
Something's not right.
The background.
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The car is a 2005 Renault Clio 182 with 78,000 miles.
The car was throwing a P0130 error [upstream O2 sensor] when the previous owner had it, so he replaced the O2 sensor with a Bosch one. It didn't last long. When I bought the car, it had the error. When the ignition on, but engine not running, the sensor was registering 1.275v. It should be registering around 0.4v to 0.5v. I replaced the Bosch sensor with a brand new Genuine Renault one [which is actually manufactured by Bosch !]. The car was running fine for a while, then it started to exhibit a lumpy tickover, was dying around 3000 rpm, and low and behold the P0130 fault code has returned.
I did quite a bit of live data logging. From cold start to running temperature at constant idle, the O2 sensor does appear to move to switching between around 0.1v and 0.8v. However the STFT appears to be oscillating with negative values at various rpm when the engine is under load [i.e. driving]. It should be oscillating around zero. So the O2 sensor is definitely not working properly. The LTFT is constant at 4.69%
The downstream O2 sensor is a Denso sensor and has been working fine.
In other information... the manifold air pressure is 369-393 at idle, so that seems around where I'd expect - i.e. it's not leaking.
I started the car from cold yesterday and had it running for around 3 mins before I took the faulty upstream sensor out. The sensor probe was very sooty - see photo - but this may have been as a result of the car being 'on choke' after starting, so to speak.
I've looked around online to try and figure out what could be killing these O2 sensors :
Fuel contaminants - unlikely as the fuel has been bought from different suppliers at different ends of the country... and I've used my local filling station with other cars and they've been fine.
Silicone in the induction system - I've had the induction system to bits and it's clean. I also fitted new inlet manifold gaskets while I was at it.
Coolant leaks - I recently replaced the coolant. The level hasn't budged a millimeter.
Oil contaminants - the car has had an oil and filter change, also the car isn't burning oil and the MOT emissions [it had one two weeks ago] were perfect.
So to coin a phrase, if I'm about to load the parts cannon for firing [not that it hasn't been liberally fired recently], my first port of call would be to replace the injectors. They sound fine, aren't issuing fault codes, but I know that doesn't tell the whole story. Thing is... I'd be replacing these on nothing more than a hunch as at this point I don't have evidence to prove they're faulty.
Thanks for reading... I'd be deeply appreciative of any suggestions on possible ideas or next steps... or questions in case I've left something out.
Something's not right.The background.
-----------------------
The car is a 2005 Renault Clio 182 with 78,000 miles.
The car was throwing a P0130 error [upstream O2 sensor] when the previous owner had it, so he replaced the O2 sensor with a Bosch one. It didn't last long. When I bought the car, it had the error. When the ignition on, but engine not running, the sensor was registering 1.275v. It should be registering around 0.4v to 0.5v. I replaced the Bosch sensor with a brand new Genuine Renault one [which is actually manufactured by Bosch !]. The car was running fine for a while, then it started to exhibit a lumpy tickover, was dying around 3000 rpm, and low and behold the P0130 fault code has returned.
I did quite a bit of live data logging. From cold start to running temperature at constant idle, the O2 sensor does appear to move to switching between around 0.1v and 0.8v. However the STFT appears to be oscillating with negative values at various rpm when the engine is under load [i.e. driving]. It should be oscillating around zero. So the O2 sensor is definitely not working properly. The LTFT is constant at 4.69%
The downstream O2 sensor is a Denso sensor and has been working fine.
In other information... the manifold air pressure is 369-393 at idle, so that seems around where I'd expect - i.e. it's not leaking.
I started the car from cold yesterday and had it running for around 3 mins before I took the faulty upstream sensor out. The sensor probe was very sooty - see photo - but this may have been as a result of the car being 'on choke' after starting, so to speak.
I've looked around online to try and figure out what could be killing these O2 sensors :
Fuel contaminants - unlikely as the fuel has been bought from different suppliers at different ends of the country... and I've used my local filling station with other cars and they've been fine.
Silicone in the induction system - I've had the induction system to bits and it's clean. I also fitted new inlet manifold gaskets while I was at it.
Coolant leaks - I recently replaced the coolant. The level hasn't budged a millimeter.
Oil contaminants - the car has had an oil and filter change, also the car isn't burning oil and the MOT emissions [it had one two weeks ago] were perfect.
So to coin a phrase, if I'm about to load the parts cannon for firing [not that it hasn't been liberally fired recently], my first port of call would be to replace the injectors. They sound fine, aren't issuing fault codes, but I know that doesn't tell the whole story. Thing is... I'd be replacing these on nothing more than a hunch as at this point I don't have evidence to prove they're faulty.
Thanks for reading... I'd be deeply appreciative of any suggestions on possible ideas or next steps... or questions in case I've left something out.
