Failed MOT on Emissions
Discussion
Guys need some advice on how to sort out the emissions. My 98 4.2 failed the MOT today on emissions, sailed through on everything else, it even passed the CO2 emissions, but it failed on HC's and Lamda. What could be causing this? A bit of history might assist in coming to a conclusion. The car has not been driven since August 2010, when I had a few health issues, and was incapable of driving her. Mot ran out in Oct, I have run her up to operating temp in the garage, just to keep the oil flowing, but it has not been on the road. As the law has now changed or is about to, ragarding insurance and road tax, thought it best to get her MOT'd ASAP. Could it be that exhaust system is a bit clogged up or the Lamda sensors are dirty? I drove it about 40 miles today to the MOT station, but did not give it any wellie. Any advice gratefully recieved.
When my 4.5 Cerb had its MOT end of January at fast idle 2000rpm it was failing the emissions test, this was with new lambda sensors new cats and no air leaks in the exhaust system. The MOT test chap has a bit of discression with what is fast idle, so we ran the emissions test at 1800rpm and it passed with all readings being well under the pass mark.
My 4.5 was a nightmare to get through emissions. I took the laptop with me and tweaked fuelling a little but the greatest effect was advancing ignition. That brought 3 of the 4 red/green indicators to green but it still wouldn't pass.
In the end the garage advise I go and get the cats *properly* hot, so I took their junior mechanic for a spin around Redditch (all dual carriageways) before returning back to the garage for a another test. This time I still had to tweek ignition but nowhere near as far, and although the car wouldn't idle with those settings for long, it was long enough for the guy to print out the results. Technically he was supposed to hold the car at those settings while his testing machine telephoned the DVLA's own system, but my Cerb couldn't be made to hold-on for that long so he took an exec decision and passed me based on the printout.
If I was doing it again, I'd want access to a friendly TVR specialist. I have no complaints about the local garage that undertook this MoT for me because they went right outside the box to resolve the little issues it had here and there, and still only charged me for a standard MoT (I contributed a little towards their Christmas fund). But the only real guarantee would be sending it to a TVR specialist.
Unless you stick an LS in I suppose.
In the end the garage advise I go and get the cats *properly* hot, so I took their junior mechanic for a spin around Redditch (all dual carriageways) before returning back to the garage for a another test. This time I still had to tweek ignition but nowhere near as far, and although the car wouldn't idle with those settings for long, it was long enough for the guy to print out the results. Technically he was supposed to hold the car at those settings while his testing machine telephoned the DVLA's own system, but my Cerb couldn't be made to hold-on for that long so he took an exec decision and passed me based on the printout.
If I was doing it again, I'd want access to a friendly TVR specialist. I have no complaints about the local garage that undertook this MoT for me because they went right outside the box to resolve the little issues it had here and there, and still only charged me for a standard MoT (I contributed a little towards their Christmas fund). But the only real guarantee would be sending it to a TVR specialist.
Unless you stick an LS in I suppose.
Many thanks for the replies guys, there are a few ideas there that I can pursue. So far as the figures go, I'm afraid I can't remember exactly, all I can remember is that CO2 was well in, HC's were 219 but supposed to be 200ppm and as far as lambda is concerned I simply can't remember. I run the car with the CATs on so they should not be loose, but it is not beyond the bounds of possibility that they have worked loose. So checking them would not hurt. Either way readings were not way off the mark, but far enough for the tester to fail it. This particular garage has got it through for me in the past so I expect them to suggest a solution, it's just annoying when she sailed through on everything else.
Mine was MOT'd a couple of weeks ago, it failed on the first fast idle test but passed on the 2nd:
1st
CO 0.02
HC 602
Lambda 1.12
2nd
CO 0.04
HC 64
Lambda 1.12
It was taken to the MOT station by Fernies and I was told the tester was messing about, the chap from Fernies was getting stressed with them letting the car get too hot etc.
Thats a huge difference and the HC is way higher than Mr Tanks, whats all that about?
1st
CO 0.02
HC 602
Lambda 1.12
2nd
CO 0.04
HC 64
Lambda 1.12
It was taken to the MOT station by Fernies and I was told the tester was messing about, the chap from Fernies was getting stressed with them letting the car get too hot etc.
Thats a huge difference and the HC is way higher than Mr Tanks, whats all that about?
Gassing Station | Cerbera | Top of Page | What's New | My Stuff