Technical Does this sound like an O2 sensor problem?

[hutchie]

I think I am having lambda sensor problems based on the symptoms below, I just wondered, before shelling out for replacement sensors, whether I am thinking along the right lines!

Juddering/Complete lack of power: Started at just 3000 revs but developed to randomly to pretty much any time there is no response from the accelerator and the car feels spluttery to the point that it could cut out at any second and then will jerk back into action and will run fine again.

Rough idling: sitting in traffic or at lights it sounds like she is going to cut out/die for a few seconds, then sounds fine then sounds dodgy again (repeat).

Engine Management Light: it’s on and reader is showing emissions problem when the codes were read it indicated a lambda error.

One of the sensors seems to have had the wire cut and re-attached with electricians tape – I have been told this is not the best as the wires are silver and don’t fix back together as well as a copper wire would and this could be causing problems.

Am I right in saying there are two sensors pre and post CAT – do both require replacing at the same time?

I have read that it’s best to get OEM sensors (at a cost of around £45 plus VAT) does this price sound about right. Or does anyone know of anywhere to get them cheaper?

If I don’t get OEM and replace with cheaper ones for half the price they are likely to need replaced more – is this right? How long would I expect to get out of OEM ones?

Thanks in advance

Hutchie

 

[rallycinq]

Might not be O2 sensor problems.

Code reader will bring up Lambda as a 'fault' but that sometimes means that the combustion process is incomplete therfore the Lambda is seeing unburnt fuel.

Get someone with Examiner clone and check the coils are firing correctly.

There is a known issue with coil drivers in early MPi ECUs, which would give the same faults as you are experiencing.

Cheers

SPD

 

[fingers99]

There are two sensors, as you say. If I understand it correctly, the pre cat sensor does the "real" work, the post car sensor monitors that the first sensor and cat are working properly.

You might try -- if the pre CAT one has been messed about with -- replacing it with the post cat one. If the sensor was the issue I'd expect the engine to run fine, but to put on the ECU warning light.

Otherwise, as RallyCinq.

 

[hutchie]

I can’t believe it’s 11 months since I posted this – I guess it is true that time flies when you’ve got children! Thanks for the suggestions above...

Anyway I finally brushed off the cobwebs, and got some new sensors to fit but when it came to fitting them the guy that was going to fit them for me says that the sensors that are fitted were cut and re-wrapped in order to extend them to allow the wrong CAT to be fitted to the car.

What am I looking at in terms of replacing the CAT with the right one – would I be able to fit a second hand one from another Seicento? And if so any ideas of the cost?

If not and it’s a new one how much am I looking at for that? I’ve had a quick look online for price but to be honest I am not that sure what I am looking for! I mean there are prices from £50 - £250! And there seems to be diagrams or photo’s of different ones.

Thanks