964 RS Failed MOT on Emissions !

[993 C4]

Could not believe it.....neither could the guy's in the garage. At idle it was within the required level but at the steady throttle requirement, it was .2 over despite me taking her out for some heavy hooning on some of our quiet b roads and returning immediately to the ramp for the insertion of the dreaded 'probe' !
She is still running the cat but wondered if anyone else has had the same problem. Standard LWT other than cup pipe and has only covered 54000 kms.
The only other thing to add is that she has been dry stored since October last year and only briefly taken out for a quick run on dry roads back in Feb......
Any pointers would be great !

 

[Richard Dawson]

Have you checked for air leaks on the inlet side?

Is the lambda probe working?

 

[993 C4]

Thanks Richard, No air leaks and yes, the lambda sensor is working.

 

[Richard Dawson]

Somedays don't cars just annoy!!!

 

[Laurence Gibbs]

what exactly did it fail on ?.2 what ? results should be for an idle CO reading of less than 3.5% and a HC reading of of less than 1200 ppm for the car to pass the test legally, unless they've very recently changed the law? I am assuming a pre 93 car . Most RS with working cat will be a lot less than 1% CO usually read about 0.01 - 0.1 % CO . HC's usually below 100 on our cars.

 

[Melv]

Assume cat working???

 

[993 C4]

Yep Melv....cat working ....and the good news is that she's now passed. I took her to another place and she sailed through without any " motor trade tweeking" required as it were. Received a full refund from yesterday's saga and as they say; all is now well. Must have been incorect calibration the first time. They have asked me if I could run it back to them on Monday so they can re check their gear. Taxing her Saturday and looking forward to some fast fun in the sun.

Cheers chaps,

Nick.

 

[ChrisW]

The only thing is, if the cat is fitted it must be working.

The alternative is to bypass it, and then the non-cat standard can be applied.

 

[993 C4]

Hi Chris, good thought, although as stated earlier the cat is working fine, so will keep as is for the time being.

 

[911addict]

Why on earth would anyone want to run an RS with a cat?!

 

[ChrisW]

ORIGINAL: 993 C4

Hi Chris, good thought, although as stated earlier the cat is working fine, so will keep as is for the time being.

Of course, and it is original.

 

[barrysmith]

I bet you took the car , with a short run and the cat and engine were cold?,

Take it for a blast 10 miles plus with some rev's and get the cat very hot, and then have it tested.

 

[993 C4]

Nope, the car was very hot before the run and still was not enough to get her through. However, as stated earlier and after a lot of head scratching, I took her to an alternative garage where by she passed straight away without any issues. Original set up are now concerned that their equipment may need re callibrating ! There have been a few "surprising" emission failures of late according to two of their employees.....?

Thanks for all your input guys......

 

[RSGulp]

It's always worth building a good, working relationship with an MOT tester. I've taken all of our cars to the same guy for the past ten years. With the RS for example, he is enthusiastic and appreciative of what makes the car so special. He understands older cars and their idiosyncrasies - and, most importantly, he is happy to apply a bit of common sense if it's needed. I always feel confident the car has been tested properly and within the MOT guidelines, but also sympathetically tested given the car's age, rather than testing it as if it was a new car.

 

[Melv]

ORIGINAL: RSGulp

It's always worth building a good, working relationship with an MOT tester. I've taken all of our cars to the same guy for the past ten years. ................. enthusiastic and appreciative................... understands older cars and their idiosyncrasies - ..........................happy to apply a bit of common sense if it's needed.

The one and only time I took the Cup Car for a MOT myself, it was ticking over on the brake test rollers and the guy wanted to get the chassis number from under the bonnet, so he pulled the petrol release cable.....nothing happened.......I knew what would happen next.....he pulled the ignition kill switch and the car died...... Doh! I'm standing six feet away -he could have asked.....(two bonnet pins....[&:])

 

[ChrisW]

When I was having mine re-tested (they will learn !), they did the same thing and I had to walk around 100 yards to prove that my car hadn't been stolen !

Thank goodness the test station was local..