K Series MOT emissions

[Steve T]

I have almost the same spec engine, DVA 1.8K on TBs, powerspeed, Emerald mapped etc and mine failed the MoT at first with Lambda and HC.......do you have an Emerald ECU?

I was permitted to use my laptop whilst at the test station to adjust the fueling at the idle and fast idle speed/load sites on the map until we got a set of pass readings, then I disconnected it for the actual test and it passed of course. I have saved this MoT setting map into one of the 3 maps for future use. I ended up with 35ppm HC, 0.11% CO and 1.02 Lambda but before I adjusted it my CO was way above th max limit and the Lambda was too rich and would never have passed.

This all depends on you having an Emerald (or other user configurable ECU), a considerate/flexible MoT tester and a laptop and a bit of knowledge what to adjust - if you have an older Emerald with just one map, you can save the adjusted map to your pc to reload before the next test.

I don't see any other way around it unless of course you have a leak etc affecting your reading or a creative examiner which are becoming rarer due to the extra vigilance. My test station had cameras installed last year to record all test activity for random audit/inspection.

Hope this helps.

[HeMan]

It is the CO that is the big problem, HC was fine.  So on the 1st Fast Idle I was 2.78% and λ 0.931 on the 2nd I was 0.94% with λ 3.738 and on the Natural Idle I was 0.90%.

I only have one previous, from 2014, which I find somewhat hard to believe (0.01%!!!) and I have had the 4-2-1 and a re-map done since then.

 

[HeMan]

Steve (sorry, I wrote the post above before I saw yours) I have just spent my morning doing exactly the same thing!

Some time ago I got the soldering iron out and made a cable and downloaded the Emerald software to create a "stealth-mode" map in slot 3 that cuts the fueling above 2000RPM on zero throttle, to try and appease the noise police at track days.  I can now switch between normal (pops and bangs on the overrun) and stealth (dull) mode from under the dash.  So this morning I just took 10 of each of the RPM points for zero load from 750RPM up to 3000RPM and saved this to the stealth-mode map.  It idles a bit rough on this map now, but do you think that will be enough (I'm not sure if you remember how much you adjusted it by?) to do the job?

I will take my laptop just in case, but it would be useful to know if you think I am in the right direction because all I am going by at the moment is "it idles a bit rough now"!

[Steve T]

It really depends on how much out it was first of all, if you go too far you will find the Lambda goes too lean and still fails as it's quite a tight window. If it helps, and it will be a bit later today, I can send you both of my map files (ie normal and MoT) so you can see where I came from and where I adjusted to at the 2 load/speed sites...I guess what I am saying is you may have got it within the required windows but it took me 3 attempts on the tester to get it inside all 3 windows (actually the HC was ok as the CAT does most of that).

The other trick is on the fast idle test, to keep the revs very steady which means keeping your foot on the pedal very still (assuming they allow you to sit in the car) as I found that during the 30 second test, I kept going out of window due to the RPM changing slightly ie by a couple of hundred RPM, it seems when you accelerate slightly the readings are quite sensitive to change for a few seconds and if you are just hanging in the window, it may exceed the spec enough to fail the test.

Let me know where to send the map files.

[HeMan]

It's OK, I got lucky!  I took it back earlier today, with laptop on hand just in case and after a bit of messing around and a few attempts we got it through!

With each of those points dialed back 10, the CO was massively lower (i.e. 0.02%) and although the λ was then high (as you predicted) a bit of messing and a few re-tries got it within the required level.  Maybe I was just lucky, although part of me would like to spend half an hour with one of those machines to get it spot on...

Anywhoo, I have a pass and have learnt a lot about emissions, lambda and ECUs in the last 72 hours

One of those things, which knowing would have saved me £60 so I will mention here for someone elses benefit, is that due to either whoever originally set my Emerald up or the guys that did the re-mapping, the Lambda is effectively a few grams of ballast.  It is wired to the ECU, but it might as well not be as the ECU completely ignores it!  Anyone want a slightly use Lambda sensor

[Richardoh]

Hi there

Just a really quick note to apologise for never responding to this question - I've only just spotted it. In the end the car did make it through but beyond getting it running really hot I don't know what else was done. I'm not the most technically minded person on this forum and was just pleased to be able to drive the car again!

I'm glad you got sorted, and the extra info may be useful in the future - we can't be alone in having this issue!

All the best

Richard

[mudguard]

Just in the remote possibility that this is of any use to anyone, here are the recent results (it passed!) from my EU3 1.8K VVC on 28k miles:

Fast idle 2675 RPM CO 0.07% HC 29 Lambda 1.016

Idle 845 RPM CO 0.04%

The tester added a note to say that the engine was warm during the test!