MOT - Emissions advice please

Keith

I'm not sure on the ins and outs of the oil change but was advised that it was a good idea before my MOT as my car does very few miles. 10 in 3 months!

Depending on the ignition system, it may be easy for the car to be made to pass and then altered back by altering the fueling via the mixture controls.

It depends what it failed on exactly what were the levels?

AliceBanned

Thank you all for so much advice.

I have arranged for a second opinion and a service at a different garage, then i will take it back for a retest. The emissions: CO2 was 0.55% on fast idle test, 0.50% on second fast idle test and 0.33% on natural idle test. How bad is this? Nothing else found during the MOT.

Thanks for any advice on this. Now i've got the awkward job of explaining to the first garage that I'm cancelling the service with them at the last minute and going elsewhere.

anewman

AliceBanned wrote: »

I have arranged for a second opinion and a service at a different garage, then i will take it back for a retest. The emissions: CO2 was 0.55% on fast idle test, 0.50% on second fast idle test and 0.33% on natural idle test. How bad is this? Nothing else found during the MOT..

If the limits are the same as mine (0.2 on fast idle, and 0.3 on natural idle) the CO2 values are rather high.

I'm not an expert, but wonder if the high CO2 could be due to over fuelling (due to a failed temperature sensor for example) rather than the converter failing - although the converter failing is still a possibility.

AliceBanned

anewman wrote: »

If the limits are the same as mine (0.2 on fast idle, and 0.3 on natural idle) the CO2 values are rather high.

I'm not an expert, but wonder if the high CO2 could be due to over fuelling (due to a failed temperature sensor for example) rather than the converter failing - although the converter failing is still a possibility.

OK thanks - perhaps it is the cat after all. I think the fuel values are about the same as the ones you quoted. they also mentioned slight exhaust rattle so who know, it might be both so at least now I'm prepared mentally that this could be fairly expensive. It's great that so many people have given advice, thank you.

AliceBanned

PS Why am I driving this old banger?! I've just driven the courtesy car - Mitsubishi - the garage have lent me and I don't want my ancient Fiesta back! Aagh, not a very moneysaving conclusion, but I'm now so tempted to look for a much newer car over the next few months! What a difference driving something from this decade.

Hintza

I know when I have taken older cars in for MOT the garage has tuned it to run a bit lean for the MOT and then reset it back again. Older cars do start to struggle a bit as more wear and tear will have an impact on the reading.

anewman

Hintza wrote: »

I know when I have taken older cars in for MOT the garage has tuned it to run a bit lean for the MOT and then reset it back again. Older cars do start to struggle a bit as more wear and tear will have an impact on the reading.

I guess my 14 year old 1.3 OHV Skoda with around 120k miles isn't doing bad then with no bodging to get it to pass. Not sure how it will fair at next MOT though.

Fast idle
CO: 0.12 (0.20 limit)
HC: 7ppm (200ppm limit)
Lambda: 1.002 (0.970-1.030)

Natural idle
CO: 0.12 (0.30 limit)

tomstickland

I'm sure some people take the car for a good thrash before the emissions test. Loads of short journeys probably don't help. I tend to make my engines sing for their supper, change the oil regularly and have had no problems with emissions.

AliceBanned

The saga continues - I have had the serviced one (yesterday) including emissons test which passed (0.35%) at the garage which did the service. To not waste the original £50 I took it back for a retest at the place which originally said I would need a new cat converter. Not a pleasant experience, lots of questions about why I didn't get them to do the work before re-test as originally planned; and I made excuses about time availability as I didn't want to annoy them, but the truth was I wanted a second opinion.

They did the re-test this afternoon, asked me to go for a walk and come back in 45 mins, not the most hospitable of requests on a freezing cold day, but I dutifully disappeared. When I returned they said still failed on emissions, still needs new cat, the other garage is wrong blah blah. I went off in a slight huff and once down the road noticed that the promised paperwork was not in the car as they had said. I phoned them, they avoided the point for a while still going on about it needing a new cat. I said "look, all I need is a print out so that I have the two garages' differing opinions in writing, and can take it from there". Surely i should have had the print out to prove the re-test, but they had not given it to me. i had to go back, and wait another half an hour in the cold whilst they put it through the test. In the meantime I showed them the printout from the garage which said in their emissions test if passed. They took it over to the phone and without discussing with me first, phoned the garage which said it passed, and had it out between them. their opinions still differ, they did a re-test, gave me a printout and said we still fail it. I phoned the other garage who did the service who now say bring it in tomorrow, we will pass it based on those values. both say they are right. This is stupid!! It is something to do with the testing machines and age of the car (1995, but surely the result cannot be this arbitrary?!! I feel like I'm on a wild goose chase. i wouldn't have serviced the car if major work was needed. Now I have to wait until tomorrow and shell out another £50, and it may fail! thanks for any support, I'm at my wit's end, broke and with no car.

Keith

What is the name of the first garage?