1.6k Series MOT Failure on emissions

[C7 Owl]

My Caterham just failed the MOT on Lambda part of the emissions test.  The garages think its because of a Cat removal.  Iam not aware that the CAT has been removed before i purchased it.  How can i confirm if it is or not?  As I was driving to the test the car was definitely a bit lumpy as it was warming up.  Which I have never noticed before.  

From reading forum main advice seems to be replace Lambda and make sure it is warm upon arrival for test and tested soon afterwards.  

Is there anything else I can do to try and sort out.  Most of my driving is on the road so dont want to keep it as a track only car.  

Any suggestions welcome.  

Thanks

[revilla]

Can you post some pictures of your exhaust system so we can see what you've got?

[John Vine]

According to DVLA, C7POA was first registered in July 2000.  If that's the car in question, it will definitely need a cat to pass the MOT.

As Andrew says in #2, please post a pic of your exhaust system.  The original for that year would very likely have an integrated cat in the front section of the silencer.  However, not all MOT testers would necessarily be aware of an integrated cat, so might well think it was missing.  Of course, you may have some other problem, or an aftermarket cat, or no cat at all! 

JV

[simon_h]

You say it's only failed on the lambda part of the test? Passed all gasses fine? Just outside the default lambda range? Put your test result up on here 

[Jonathan Kay]

And any previous emission analyses that you can find, please.

Jonathan

[C7 Owl]

I'll just nip to garage to take a picture.  I'll take one of the engine bay too.  Can someone help identify if the engine is EU2 or EU3.  Just in case I do need a Lambda sensor.  Here is the latest Emissions test.  

IMG_20221028_0001.pdf

[John Vine]

If you have a distributor at the rear of the cam cover, it's EU2. If not, it's EU3.

JV

[C7 Owl]

The only other emissions document is the IVA test sheet.  None of the other tests I have, failed it on emissions and did not include the sheet.  

IMG_20221028_0002_0.pdf

[C7 Owl]

So could be CATs been removed at some time in the past and testers have turned taken a view test not required until now, or it could be that Cats still in place and problem with the emissions equipment on car.  

[John Vine]

Re #6:  Here is the latest Emissions test.  

Did you manage to post this? Nothing has appeared yet.

Re #9:  Yes, either of those could apply, although I'd doubt that a tester would ignore a missing cat where one is needed.  We'll know more when we see a pic of your exhaust.

Out of interest, is the car a recent purchase?   If so, is this the first MOT under your ownership?

JV

[Jonathan Kay]

I can see the image in #6. It's probably that PDF viewing problem.

Hang on a minute... now reposted as JPEG. Any better?

Jonathan

[Jonathan Kay]

[simon_h]

I could see it on the phone but not on here. Anyway, its very unlikely your car is so clean its producing nothing that can be measured. A modern real car can be really low but zero's everywhere? Not likely. The lambda reading is so far lean it would be misfiring, as an example a lambda of 1.2 is around 17:1 afr. My rough calc suggests your result is around 21:1 afr.

I would suggest getting it sniffed somewhere else before doing anything as I think their machine is probably faulty or they have a massive air leak in the sample pipe.

[John Vine]

Well played, JK!  Thanks.

I'd say from those results that either there's a severe exhaust leak post-sensor (edited: not "pre"), or the sensor/wiring is at fault  The lambda range of 0.95-1.09 is correct for a 1.6K.  But surely those actual CO+HC results aren't real values?  Did the tester suspend the test when he registered the lambda values? 

First of all, check the Econoseal connector for the sensor (they can get badly corroded).  If that's all ok, replace the sensor.

JV

[Dave Hardcastle]

Of course, someone could have installed software by VW!!  (OP, don't take this seriously)

[John Vine]

#13:  Interesting.  I'd not considered a faulty gas analyzer!  Good suggestion to try another testing station.  If that shows all is ok, presumably the OP could get a refund for the first test?

Nevertheless, the OP did report in #1:

As I was driving to the test the car was definitely a bit lumpy as it was warming up.  Which I have never noticed before.  

Maybe there's a sensor-related problem after all?

JV

[simon_h]

Maybe there is a sensor problem. If its really running that lean you would expect HC's off the scale due to partial burns. CO would be sort of ok though.

If it was a leak pre sensor then the fuel trims would have to richen up to compensate. It could be a leak post sensor diluting things. Have to remember the lambda value isn't from the sensor but the sniffed gasses.

I guess if the car is genuinely ok elsewhere then taking the result to the original test centre could give cause for a refund or you could report them to the authorities to get the machine checked out. 

If the sensor is dead and the result valid I would expect the engine to be running open loop and yes the lambda would be a little outside the limits but no car with a cat fitted is calibrated to be that far away from stoic in the emissions region full stop. Well unless its set up by an amateur who has no clue what they are doing. 

[C7 Owl]

Here are the pictures of the exhaust set up.  How do I tell if the cat has been removed.  Do I have to remove it from the hangers and pull exhaust off?  

[C7 Owl]

I did notice on the way to the test centre the car was spluttering at lower revs which I had never noticed before.  Wasnt exactly a misfire.  

Redline have asked me to identify if engine is using distributor or coil pack.  

From looking at the part this looks like a distributor.  Am I right?  

[revilla]

That looks like the exhaust with the integrated "cat in can". To be sure, have a look from underneath so you can see behind the head shield. If it has the cat, there will be a welded seam around maybe 8" back from the front edge, and probably an obvious difference in the metal in front of and behind the joint. To be honest I think I can just spot the join through one of the holes in your heat shield so I'm fairly sure that will have a cat.

[revilla]

Yes that's an EU2 engine with a distributor.

[John Vine]

You definitely have the standard exhaust for the year, with integrated cat.  The whole set-up looks like this, with the seam between cat and silencer arrowed:

From the discussion so far, it looks very much as though your emissions test was a wash-out, due possibly to faulty test equipment.  An emissions test at another testing station should provide confirmation, so delay fitting a new lambda sensor until then.

Out of interest, did your tester pass everything else on the car? 

JV 

[John Vine]

#17: It could be a leak post sensor diluting things.

As the standard exhaust doesn't have any joins post sensor (edited 30Oct22: Ah, but it does! The sensor sits at the base of the 4-branch, so the join to the silencer pipe is definitely "post") I'm beginning to wonder whether the tester managed to insert the probe far enough into the silencer?  I know my MOT guy (who is very au fait with 7s) sometimes has trouble getting his probe right round the bend (as it were).

JV

[C7 Owl]

Thanks for all the input.  So the consensus seems to be.  There is a cat.  It might be the test station.  The only thing is I have now taken it two stations.  The first was a new one, the second is further a field from my new garage but I have taken to and its passed before.   Kicking myself for trying to save 30mins each way.  Both treated me like I was trying to pull a fast one.  Saying id taken the cat out.  Im a bit hesitant to pay another £55 to get accused of being an emissions villain!  Is the next step replace the lambda sensor?  

[C7 Owl]

I hadnt realised needed to be JPEG.  Looked on the back of first MOT this year and it had the emissions on it.  Missed it this morning.  Here is IVA test 22 years ago also.