MOT Emissions Failure

Mr_Stroudley

Hi, Our 2003 Honda Civic 1590cc failed the Fast Idle Lambda Tests (1.039 and 1.035). I took the car away, despite thus losing the opportunity of a free retest there and having a £50 diagnosis offered, as I felt uneasy by what I was being presented with. All CO and HC readings on the printout were "0". Now over the years I have usually had some % or ppm noted, though always within limits, and certainly not all reading "0". I suspected that the test was flawed in some way, but would appreciate an informed opinion as to whether I am right or not. Is there anything in the meantime that I should check or do? Thanks...

Hammyman

I agree with you. HC ALWAYS shows something, even on a brand new car. I have had 0 on the CO but on a car with a faulty carburettor that was running so weak I was surprised it ran at all.

Mr_Stroudley

Thanks for the confirmation Hammyman. I would like to know just how this printout was arrived at then. I know they stick a probe into the exhaust, but even if it was not pushed fully in it would still show some HC ppm emission surely? Seriously starting to wonder if the probe went anywhere near my car, but again would greatly appreciate informed input.

fivetide

Where are you based? Some councils offer free emission checks. Might be worth checking if they have anything going...

Mr_Stroudley

I'm in Crawley, West Sussex, and the only thing I've come across is their "Green Guide" that encourages me to go by bus! The nearest Local Authority MOT Testing Station is in Horsham I think, would they do a free emissions test? I thought they only do MOT's.

fivetide

Not sure but you could call and ask.

If that is all it failed on then perhaps it could be worth a go with them? You'll need to pay for another test anyway. Not sure if you can then make a complaint about the initial test and get some money back. Sure someone else will know!

5t.

Lum

Could just be that once it failed the lambda test they didn't bother with the others?
Have you asked the MOT place to explain the numbers yet?

Mr_Stroudley

Not yet, I just reasoned that the tests would note all the readings as they were done, ie the two Fast Idle and the Natural Idle Tests. You maybe right though, again it needs someone experienced in how these tests are conducted. As to asking at the time, I didn't as I needed time to collect my thoughts and get some independent advice, like from MSE! :money: I was getting a lot of pressure to OK a diagnosis, and was told that I could be in for a new sensor and/or Cat. I might well be of course but prefer to come to that conclusion when I am better and independently informed.

Lum

Lambda sensor is probably an easy enough job to do yourself, it's basically like changing a spark plug only you need a special socket (costs a tenner) to do it. Just check where it actually is on your car though as some are in a really awkward place.

Mr_Stroudley

Yes, I changed one previously on a Carina, but that was indicated by a fault code with an Engine Management Warning. This time it could be anything or nothing, and if the latter of course I just need a retest (after a good 20 minute thrash?) to get it renewed. I need feedback on the "0" CO/HC readings first though. If informed opinion is that it was a bad test I could go back to the MOT station and confront them with it and perhaps get a free retest. Without that though I'll get more of the same blarney and invited to empty my wallet.

fivetide

I'd have expected a failed lambda to chuck up some sort of fault either the engine light or an exhaust one (if your car has it. Certianly on a 2003 Civic I'd expect the ecu to be checking things like that.

A good vote for the 'italian tune up' did you watch them do the test? was the car really hot when they did it? Things like that make a huge difference of course.

I'd be tempted to see if someone can check the emissions for you without actually doin the MOT test. If it proves to be good, then as you say, you can confront them with it and see what they say. If there are no faults showing up on the car, I'm not sure what difference plugging it into a laptop would do either, presumably it will not report a fault to them so the diagnostic seems a bit silly.

If the cat was blocked the car would not be running right I'm sure. The two times I've seen that it has been blockign the exhaust and stalling the car, bit like the old 'banana in the tailpipe' from Bevverly Hills Cop.

No harm in a second opinion really.

5t.