Petrol engine catalyst cleaner

[Fastpedaller]

A new one to me..... The EML lit on our Daughter's car. RAC came to the rescue (she lives 100 miles from us) and diagnosed a problem with one of the oxygen sensors. The garage local to her plugged it in today and declared it was the catalyst needed cleaning. A fluid put in the fuel tank and a steady fast drive should clean it out apparently. Anyone else have experience of this?

 

[Drago]

I did it once and it worked.

About 20 years back I got caught out by the Tesco silicone contaminated petrol incident on my beloved Mi16 (a car, not a Russian attack helicopter)

The emissions lights same on so I rammed a double dose of cat cleaner through at it worked for me.

Ultimately you've got nothing to lose beyond the cost of a bottle of cet cleaner, and best case scenario it may work and save your lass £££s.

 

[gbb]

So RAC diagnosed the oxygen sensor...did it get replaced ?
Then garage diagnose the CAT needs cleaning ?
Seems to me you have two different outcomes for the same problem.
I'd want to verify the sensors state, working or not ? replaced or not ? before I moved any further, you might be paying for works that might not need doing

 

[OldShep]

So RAC diagnosed the oxygen sensor...did it get replaced ?
Then garage diagnose the CAT needs cleaning ?
Seems to me you have two different outcomes for the same problem.
I'd want to verify the sensors state, working or not ? replaced or not ? before I moved any further, you might be paying for works that might not need doing

The RAC diagnosed the reason for the EML coming on. Not faulty just doing its job.
The garage diagnosed, from experience no doubt or after a test on the sensor. the reason for the Oxygen sensor to trigger.

 

[CXRAndy]

I have used a cat cleaner. Wasn't totally convinced it cleaned the cat. I had actually thrashed the car to superheat the catalytic converter. It passed the MOT- just. Over the winter I replaced the catalytic converter with a new one and the car sailed through emissions.

If the car has two sensors, one before and one after the catalyst.

A good scanner can display the outputs. The pre 02 sensor, should swing in a sine wave when in closed loop. The post sensor should be almost a flat line in closed loop when the catalyst is fully warm.

To test the sensors are working. Pump the brake pedal rapidly and repeatedly to force a lean condition in fuelling. The sensor up and downstream will reflect the lean condition.

Then force a rich condition by squirting a small amount of brake cleaner into the air inlet. Again the sensors will react to show this.

If the post catalyst sensor is swinging in a sinewave like the pre sensor this indicates the catalyst is worn out.

 

[CXRAndy]

What car is it and year

 

[fossyant]

Worth a try with cat cleaner and a good run I'd say, but start to budget for new sensors and a cat. Not cheap. Happened on my Nissan. Was passing emissions tests but would throw the Engine light every so often with the same code. Garage said just keep resetting it (this is where an ODBII is handy. I asked them to replace the cat and sensors as I kept the car another 10 years.

 

[figbat]

Oxygen sensors fail, it’s quite ‘normal’. The AA diagnosis could be down to a failed cat or could have been a bad sensor, it depends on precisely what error message they found. For the sake of a few quid it’s worth getting your own OBD code reader so you can check this stuff out yourself. Then simply Google the code you get.