19 replies to this topic

[bedfordbeagle]

Last thing I expected! 93 spi cooper failed mot on emissions.

Can anyone offer advice as to where to start looking.

Have read through many of the posts on spi emissions but can find nothing similar to this:

The car drives faultlessly - revs settling to between 850 & 950 once warm, spark plugs correct colour, averaging 36mpg, starts first time every time, no smoke, no exhaust leaks identified. Temperature stays bang on centre once warm regardless of load. ( we have also fitted a vacuum gauge - pointless I know - but it is very responsive to any throttle activity and 'dies' if we unplug any of the vacuum pipes so I assume no leaks.)

Mot emission Readings as follows:

CATYLIST EQUIPED VEHICLE WITH CLOSED LOOP CONTROL
Fast idle test (2450-3050rpm)
CO: limit =< 0.3%, actual 2.47% fail
HC: limit =< 200ppm, actual 134ppm pass
Lambda: limit =< 0.95-1.09, actual 1.037 pass

Second Fast idle test (2450-3050rpm)
CO: limit =< 0.3%, actual 2.33% fail
HC: limit =< 200ppm, actual 169ppm pass
Lambda: limit =< 0.95-1.09, actual 1.037 pass

Natural idle test (725-1025rom)
CO: limit =< 0.75%, actual 1.60% fail

Last years mot emission results from previous owner:

(2013) NON-CATYLIST EQUIPED VEHICLE
CO: limit 3.5% actual 0.044 pass
HC: limit 1200 actual 1200 pass

We acquired the mini two days after this mot date. It had a cat and no evidence or recent removal (bolts undisturbed). We did notice that the air filter wasn't bolted and the vacuum pipe from air filter to fuel trap was unpluggged. There was an advisory of rear silencer leak and have replaced with sportex 2" rear box checked and no leaks. All vacuum pipes and elbows have been renewed.

Suggestions include: lambda sensor failed, cat failed, coolant temperature sensor failed, locked in limp home mode etc.

Is there anything obvious from the readings that can narrow down my search for a solution??

Edited by bedfordbeagle, 30 September 2014 - 10:22 PM.

[jamesquintin]

My MPI failed on emissions once or twice. Mechanic suggested it was the Lambda sensor. I bought one but never got around to fitting it, took car back for MOT and it passed... Been fine ever since

Finally fitted the lambda sensor 4 years later when I replaced the LCB...

Q


 

[Guess-Works.com]

You cat's probably fubar...

 

With the HC and Lambda in range then the engine is running fine, just the cat's not doing it's job of cleaning up the exhaust,

[quicksilver]

i took off the cat on my 92 spi when it fell apart and replaced with a de cat pipe.... has passed emissions every time no problems... maybe the test parameters are different for cars without cat on - maybe remove and re try without it?

[bedfordbeagle]

Thanks guessworks - is there any easy way of checking the cat before committing to purchase?

Quicksilver thanks but I was advised by the mot station that as a 93 rather than 92 apparently cannot decat unless I can prove an older engine fitted - vin number effectively states cat. Or rather I can decat but as a 93 it would be tested under cat criteria rather than just gas flow (ie CO at =< 0.3% rather than TBi CO at =< 3.5% - so would probably fail as emissions likely to be further out than with a cat.

[Guess-Works.com]

Not really, but you'll be surprised how much a new cat will clean up the exhaust, plus will probably make the car perform better as well as cats can get fairly 'guffed up' over the years.

[bedfordbeagle]

Thanks Guess-Works - took the plunge - bought a new (cheap) cat. Took the old one of and what do you know - empty inside!!! Fitted new one emmissions now within correct limits - ta-da - 12 month mot :)

 

Only problem to solve now is the new cat sits at 45 degrees and grounds out on anything larger than a grain of sand (exagerated). Well I've got a year to sort that out onless I tear it off on a bump.

[Guess-Works.com]

have you got it the right way round, as the holes at each end are offset ( or should be )

[bedfordbeagle]

Arrow indicates direction of flow. But the angle just looks wrong!

Before (old empty cat):

Ater (new Klarius cat):

 

[RedRuby]

Difficult to tell and may be a stupid suggestion but would it sit better if you rotated it through 180 degrees?

[Badboytunes]

Maybe that is why it was cheap, as in the flanges have been welded on in the wrong position.

[bedfordbeagle]

Already tried 180 degrees - made no difference.

The parts shop is getting another one in to check and compare with original one.

 

One thing I do need to check - as the original had been "gutted" it may have been fitted back to front (no arrow on it to identify flow) - this may affect the lie of the rear pipe & box.

 

My brain cannot cope with predicting the outcome of rotating and flipping trapeziods so i'm off to make some cardboard models.

[bedfordbeagle]

Models done -

If i flip the cat front to back then it fits - the arrow on the cat will then be facing the wrong way - ie to the front (incorrect according to the basic installation sheet)

 

So - new question to sort the problem:

Does it matter which way round the cat is??

[Guess-Works.com]

As far as I'm aware it'll not make a difference regarding the honeycomb in the cat, but there may be design implications...

[Alpenflitzer]

I am driving an SPI 1993 and to me it looks like this new cat is the wrong one for your car. It is too short and therefore to thick that is why it cannot fit.

 

Have a look in ebay/amazon or Minisport/Minispares.