New catalytic converter break in warm up procedure

digi · Jul 17, 2015

What's the proper or correct method of breaking in or warming up a new catalytic converter.

I've been and got a new cat so want to make sure i install it correctly as this will be my last attempt at getting it to pass the emissions test or i'm going have to get another car for the daily drive to work.

Longbolt · Jul 17, 2015

First thing i would do is install it making sure there is no exhaust putty around the entrance to the cat.

Then, before going through the test again, i would take it for a good high speed run up a motorway if possible and get the cat up to a high working temperature.

Cats are more efficient running extremely hot.

Good luck on the re test.

B34R · Jul 17, 2015

If it's an aftermarket (cheap) one they generally are packed with expanding substrate, to activate it/expand it you're supposed to:

Fit cat
Start car, allow to idle for 5-10 minutes
Hold car at 2500rpm for 2-3 minutes

Shut down, allow to cool completely.

digi · Jul 17, 2015

Yes it's an after market cat as i cannot justify spending £849 for one from land rover as it's more than the cars worth.

I will follow your warm up procedure as it makes sense, i'll fit it tomorrow then take it for the retest on Monday nice and hot, fingers crossed.

digi · Jul 18, 2015

I fitted the new cat today then did the warm up procedure, let cool down until it was cold.

The exhaust fumes are nice and clear but i think i may have another problem with 2nd lambda sensor, after returning from a short drive to get the car up to operating temperature i plugged my scanner in on live data, sensor 2 post cat is giving 0 volts most of the time on idle then moves slightly around upto 0.1v, when i run the engine at 2500rpm it drops back to 0v.

Does this look to be a faulty sensor, what voltage reading should i be getting on the post cat lambda sensor.

Sorry for all the questions i'm starting to even annoy myself thinking i should have thrown the towel in but don't really want to part with her.

Nodge68 · Jul 18, 2015

digi said:
I fitted the new cat today then did the warm up procedure, let cool down until it was cold.

The exhaust fumes are nice and clear but i think i may have another problem with 2nd lambda sensor, after returning from a short drive to get the car up to operating temperature i plugged my scanner in on live data, sensor 2 post cat is giving 0 volts most of the time on idle then moves slightly around upto 0.1v, when i run the engine at 2500rpm it drops back to 0v.

Does this look to be a faulty sensor, what voltage reading should i be getting on the post cat lambda sensor.

Sorry for all the questions i'm starting to even annoy myself thinking i should have thrown the towel in but don't really want to part with her.

Quite normal for the post cat O2 sensor voltage to be up and down. If the MIL is off, it's of no concern. The post cat O2 sensor is an emission requirement, nothing more. The engine ECU takes mixture information from O2 sensor before the cat

B34R · Jul 19, 2015

I think that's actually a good sign, means that the cat is doing its job regulating the output down the exhaust.

Best thing to do is get the emissions tested by the garage and see what's happening!

digi · Jul 21, 2015

I put a new bosch lambda sensor on just in case but it still failed the emissions test, the CO was 1.17, lambda was 1.046, i don't know what else it could be, it's running nice and clean know but still will not pass emissions is there anything else i can check.

B34R · Jul 21, 2015

This is bizzare...
Do you have a code/data reader?

Check the coolant temperature sensor, exhaust leaks and it's entirely possible that oil has killed the pre-cat Lambda sensor.

digi · Jul 21, 2015

I have code/date reader, i don't get any fault codes, on live data lambda sensor 1 switches up and down between 0.1volt to 0.8volt, sensor 2 switches between 0.6volts to 0.8 volts sometimes dips lower.

The coolant temperate sensor works as i get a reading i can see it rise as the engine gets warmer.

When i fitted the new cat, i used new gaskets, the post cat gasket i used with exhaust paste, the gasket between the maniverter and cat i only used the gasket no exhaust paste, as it said don't use exhaust paste in front of cat, should i use exhaust paste on the gasket before the cat, i'm clutching at straws now, if air was getting in here would i get an high CO & lambda reading.

teddywood1 · Jul 22, 2015

when we take the wife freelander for the test they do the test then reset the machine and do it again they said those old rover engine's are terrible for passing the emissions test,

New catalytic converter break in warm up procedure

digi

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Longbolt

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B34R

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digi

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digi

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Nodge68

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B34R

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digi

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B34R

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digi

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teddywood1

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