mazda failed nct emissions

Jordan5372

Hi

Got a Mazda 323F here that failed emissions by 0.2 %

drove it hard to the test centre and cat was hot. I was told i need a new CAT for it to pass.

however, would it make any differene if i were to add STP to the tank before the retest?

ION08

Jordan5372 wrote: »

Hi

Got a Mazda 323F here that failed emissions by 0.2 %

drove it hard to the test centre and cat was hot. I was told i need a new CAT for it to pass.

however, would it make any differene if i were to add STP to the tank before the retest?

How do you mean it failed emissions? Can you be more specific? .... Low Idle / High Idle? What were the values?

Jordan5372

I am not sure of the specifics as it wasn't me who took it, all i know is it failed by 0.2% on high idle.

ION08

Jordan5372 wrote: »

I am not sure of the specifics as it wasn't me who took it, all i know is it failed by 0.2% on high idle.

If it only failed on High Idle it could be down to a dirty, clogged up air filter restricting airflow into the engine.

Id recommend changing Air filter, Oil and Oil Filter, Spark Plugs and use "Dipetane" in the tank as opposed to STP.

I've researched this myself recently as my girlfriends car went in for the NCT and also failed emissions on high idle.

I took it to a garage with emission testing equipment. Once the dirty air filter was out, the CO% levels improved significantly.

Following that, I gave it a full service as above (Air Filter, Oil Change, Oil Filter, New Sprak Plugs and added Dipetane to the tank)

It is going in for the retest tomorrow so I'm hoping it'll pass.

biko

Try a full bottle of Dipetane and take it out tonight and drive it hard, then again really hard before test (keep it above 3500rpm).
It's not a sure-fire way but may work.

ION08

biko wrote: »

Try a full bottle of Dipetane and take it out tonight and drive it hard, then again really hard before test (keep it above 3500rpm).
It's not a sure-fire way but may work.

Would a full bottle of dipetane not be bad for the engine??

Im taking the gf's car in for its retest tomorrow morning, im wondering should i throw in the remainder of the bottle of dipetane?

Theres close to 40 litres in the tank and 1/4 of a bottle of dipetane....

Jordan5372

just bought a bottle of STP petrol treatment, it says on the back to add to a full tank of fuel, is a full tank really nessecary?

ION08

Jordan5372 wrote: »

just bought a bottle of STP petrol treatment, it says on the back to add to a full tank of fuel, is a full tank really nessecary?

If we were to say yes, you probably still wouldnt listen... considering two people recommended Dipetane yet you still bought STP

Jordan5372

yes but the nearest garage that sells dipatane from me is 30 miles away..... STP was in my local petrol garage, it only need to drop emissions by 0.2 %

ION08

Jordan5372 wrote: »

yes but the nearest garage that sells dipatane from me is 30 miles away..... STP was in my local petrol garage, it only need to drop emissions by 0.2 %

Fair enough, but just so you know 0.2% is quite a lot. 0.2% is the absolute limit for high idle emissions so if you failed by an additional 0.2% it means your car is putting out twice as much CO% as the absolute maximum allowed ... Just to put it into perspective for you!

Jordan5372

was in a garage today and the guy doing the emission test said it wasn't out by that much and a bottle of that treatment might just work as it has with many others.

biko

ION08 wrote: »

Would a full bottle of dipetane not be bad for the engine??

"There is no danger from putting in too much Dipetane."
http://www.dipetane.ie/Motorists.aspx

Jordan5372

The car has been sitting up since last august, went for emission test today in mechanic garage with old stale fuel in it. Would a tank of fresh fuel, a bottle of the additive and a good blast down the motorway on high revs to heat up her, she might be ok?

biko

She might yeah. If I was you I'd put a whole bottle Dipetane in and drive it like stolen.
Then take it to emissions test again immediately after.

If it passes I'd make a NCT appointment.
If it still is not working then look at getting a new cat (or a working cat from a breakers) before going to NCT.
At the end of the day it's up to you if the car is worth it.

Jordan5372

was thinking on booking an NCT and putting in the additive with a tank of fuel and driving it very hard to NCT along motorway, taking test and hoping for the best. If it fails i have 30 days to order a CAT and get it installed. The Car is a Mazda 323F 1.6 2001 model, seen this online that i think would fit. Need a second opinion.

http://www.cats2u.co.uk/product_info.php?products_id=30033

biko

£146.60 seems reasonable.
Ask local exhaust centres, they may do a good deal and include fitting.

ION08

Jordan5372 wrote: »

The car has been sitting up since last august, went for emission test today in mechanic garage with old stale fuel in it. Would a tank of fresh fuel, a bottle of the additive and a good blast down the motorway on high revs to heat up her, she might be ok?

Well i hope it works for you but in your first post you said that it failed BY 0.2%
If 0.20% is the limit and you failed BY 0.20% im assuming your fail result was 0.40% which is TWICE the maximum limit.

Youd be doind well to HALF your emissions using just Diptane, let alone STP.

Jordan5372

can someone help me understand this please "10/00-02/01"

http://www.cats2u.co.uk/product_info.php?products_id=30033

ION08

Jordan5372 wrote: »

can someone help me understand this please "10/00-02/01"

http://www.cats2u.co.uk/product_info.php?products_id=30033

Manufacture dates of the car in question

October 2000 - February 2001

It may not even be an issue with that cat, but tis your money!

ION08

Just read back over the thread...

On one hand you're saying things like:

Jordan5372 wrote: »

the guy doing the emission test said it wasn't out by that much and a bottle of that treatment might just work as it has with many others.

Yet on the other hand you are jumping to conclusions and looking at replacing major parts like the Catalytic converter, which once you consider the fact that it costs £175GBP, factor in currecny conversion, shipping costs and fitting costs once it arrives, you'd be looking around the €250-€300 mark

The's fairly expensive so you'd want to be sure that's whats actually causing the problem, which is hard to determine considering you dont even know your full NCT emissions results (like your Lambda reading, your exact CO% and your HC ppm , all which appear on your NCT fail sheet and will give you a better indication as to the possible cause of the problem)

Do you not think it might make more sense to start looking at the simpler and cheaper things that may be causing your high emissions?? Like, as I already mentioned; Air Filter (less than €10) Oil Filter (less than €10), Fresh Oil Change(€30) .... espcially since you say the car has been laying up since last August!!!

Then once all of those small but common issues have been ruled out and if your emisssions thereafter still above the limit should you start looking at things like CAT's and other major causes of high emissions. Otherwise you could end up spending €250-€300 replacing a perfectly good CAT yet your emissions could still be off due to something silly like a clogged air filter or oil filter

Anyway, first step is to actually KNOW exactly what your NCT emission results are to begin with before you begin troubleshooting.

Have a read of this link to give yourself a better idea/understanding:

http://www.auto-repair-help.com/auto_diagnostics/diagnose_emission_test_failure.php