Vauxhall Zafira b 1.6 - Minor Co emissions failure | Technical matters | Back Room Forum

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Tue 22 Oct 2019 05:10

Vauxhall Zafira b 1.6 - Minor Co emissions failure - Dantimp

Hi.

I after a little advise, has anyone had any dealings with Co emissions failure??

Mine failed last week

A few people have told me just to service it, take it for a thrash and get it retested making sure then engine is hot. It only failed on Co slightly high. Passed at idle and had 0.39 and 0.44 at 1st and 2nd fast idle. What do you think?

I can't find any vac leaks. My Long Term Fuel Trim reaches up to 7% which from what I have researched isn't excessive.

I can't feel any exhaust or manifold leaks either.

Do you think the service and taking it to the test station hot will pass it?

Cheers

Dan

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Tue 22 Oct 2019 09:11

Vauxhall Zafira b 1.6 - Minor Co emissions failure - elekie&a/c doctor

An mot fail with a slightly high Co reading ,is usually an indication of a problem with the catalyst. May be some of that magic juice in the tank followed by a fast run to get the cat to max temp will help it along. If the car has one of those cheap as chips cats fitted, these can take a long time to work efficiently.

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Tue 22 Oct 2019 09:36

Vauxhall Zafira b 1.6 - Minor Co emissions failure - edlithgow

The OP, like me, may not know what this "magic juice" is, of which you speak.

I've heard of people putting some ethanol in the tank before a test, to lean it off a bit and maybe raise the octane level a bit,.

I'm not sure if that is appropriate with an exhaust catalyst, since I've never had one.

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Tue 22 Oct 2019 18:26

Vauxhall Zafira b 1.6 - Minor Co emissions failure - Dantimp

So I have just had it retested after the service and a blast and has still failed.

My personal thoughts are the cat due to the lambda 2 readings when hot are up and down. Should they be fairly steady.

However just on the way back the spanner light has just come on with P1113-01 Port deactivation position sensor circuit high voltage.

I've seen some threads with a work around for this. Could this be a relating factor?

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Tue 22 Oct 2019 22:41

Vauxhall Zafira b 1.6 - Minor Co emissions failure - Dantimp

my heads going round in circles wondering what is causing it therefore here is a summary. What are your thoughts?

Issue
Emissions failure on Co only.
Get p0420 code for Cat Efficiency.
No codes for lambdas.

Symptoms
Car does smell fumey. - has done for a while.
No running issues
No real idling issues -the odd time at lights I think it will rev a little up and down but so does my astra.

Things I have done so far:—
Full service, plugs air filter, oil and filter.
Can't hear see or feel any exhaust leaks at various rpms
Can't hear see or feel any vacuum leaks.

Diagnostic findings.
o2 sensor 1 - heater always seems to be active and voltage fluctuates as I think it should.

o2 sensor 2 - heaternot always active, when inactive voltage is around 4.7mv. When active it moves around a lot and seems to mirror sensor 1 closely.

LTFT & STFT appear not far off. Ltft maybe a little high but at 7 from what I have researched is not too bad and only really an issue above 10.

My Thoughts
o2 sensors appear to be working with no error codes. However should the heater always be active?

My next steps
I'm thinkinh to change the CAT due to the sensor 2 mirroring sensor 1. Therefore showing the Cat isn't doing what it should.

Things I haven't really yet considered though.

EGR valve. From my data the EGR always seems to be inactive, EGR Feedback always seems to be incorrect. EGR Commanded position always 0% and position feedback always 0.98%. Is this normal? I don't get any error codes for EGR valve.
I haven't don't any research into the EGR yet, will do that tonight.

Interestingly though the other code I mentioned earlier P1113 for the port deactivation, this has come up for the second time today. Both times have been after the 2nd start up from the initial MOT and today after the emissions test. Could this just be somthing to do with the testing. It seems to clear itself.

Once again I really appreciate your time.