First MOT today. Car has a turbo back piper exhaust with 200 CEL cat fitted, but failed the MOT on emissions - roughly double the pass mark :(

Anyone been in this situation and can offer any advice?

I'm assuming this is down to the sports cat in the downpipe. I don't have the original exhaust so swapping is out. Phoned Piper for advice, they only open business hours.

Is there anything else that could cause this other than a defective cat? The MOT chap said all other readings looked fine and he gave it a load of revs for a load of minutes beforehand.

First MOT today. Car has a turbo back piper exhaust with 200 CEL cat fitted, but failed the MOT on emissions - roughly double the pass mark :(

Anyone been in this situation and can offer any advice?

I'm assuming this is down to the sports cat in the downpipe. I don't have the original exhaust so swapping is out. Phoned Piper for advice, they only open business hours.

Is there anything else that could cause this other than a defective cat? The MOT chap said all other readings looked fine and he gave it a load of revs for a load of minutes beforehand.

**** the bed you dont need that. i say post it on the mk5 forum. more guys with 200 cell cats, although i have never heard of a 200cell exhaust failing emission. you could possibly have a 100 cell exhaust or mayvbe your cat has broken down. if your car is over fueling could that ruin emmissions

Yeah, I'll post it over there too.

Not sure on the fueling - wonder whether taking it back to stage 1 would make any difference.

Trouble is, I don't want to make any assumptions and stick a new CAT in there, presumably from Piper (or even a new down pipe from Pipe-werx - did that mate up to your Piper cat back with no trouble?) only for the emissions to still be high for some other reason.

Arggggggh!

Beginning to see the down side of this modding lark.

chances are its not the cat it prob down to the map overfueling etc etc as a 200cell should breeze through an mot

poss lamda sensor fault

any fault codes on the car

who did the map??

No fault codes on the car - it's running a Bluefin stage2+ map.

The map itself is the de-cat version of the software.

It's got an uprated fuel pump fitted too if that's relevant.

I'd put the map back to standard, or st1 if you have multi maps on the bluefin, to eliminate any overfueling and make sure the engine is realy hot when getting it retested - I used to have a Civic which only passed when it was fresh from a run and nicely hot.

Yup that's the plan - standard map going on tomorrow, then I'll see if the MOT place wouldn't mind testing just the emissions to see if it's made a difference.

If not, that's where the real fun starts I suppose. Might just book it in with JKM and let them do all the investigation work that I'm bound to struggle with

If I can at least narrow it down to someone specific, even if that turns out to be the CAT, at least I know which direction to follow.

Which part of the emmisions did it fail on?

All of it, on CO.

Fast idle: 0.53% (limit 0.2%)

Second fast idle: 0.5%

Natural idle: 0.59% (limit 0.3%)

Everything else was ok emission wise - Lambda and HC.

Just in case,

Have you replaced / cleaned the air filter and air intake?

No, but it's only been on the car a few months - although I have been up and down the motorway every day this winter so the salt could be building up on the filter - especially as it's in direct line of sight of the air flow - I'll check it later today and see what it looks like.

Would a caked filter lead to these problems though?

I think it might, because the CO is high that means the mixture is too rich.

If the air sensor if gunged up then it might think its getting more air than is actually going through.

Also along these lines a split pipe, joint causing an air leak; can cause problems.

Ta for the advice cbx040.

Car is back to standard now, so I'll see if the garage can take a reading on Tuesday morning - I'll also do a visual inspection of the MAF, but I assume the filter should do its job and block anything nasty getting through.

After that it's JKM time I think. Assuming it's NOT the CAT, the only other thing I can do is rule out the other suspects one by one until the readings drop below an MOT friendly level - don't think the garage will stretch to renting out their emissions equipment for a while so I'll call in the experts!

Wish they were a bit closer

When mine had it's MOT in December the tester (who visits the forum from time to time) actually rang me to comment on how remarkably good my readings were! That's with a stage 2 map (the one that was on my car when we met Tim) with a Milltek downpipe and sports cat.

Well I'm interested to see what effect taking the Bluefin off has on the emissions.

Regarding the data logging, found another post elsewhere that had the same logging trouble as me, only to be told by SC that it's a diagnosis tool for SC and not for the general public to use - interesting given the instructions are included in the Bluefin software. Guess this is a good get out clause based on the fact that logging clearly doesn't work.

Is your new pump and stage 3 going to be putting in an appearance on JKM's rollers in the near future Ben?

It depends when the pump arrives.. I haven't received it yet and haven't heard anything. I don't have a lot of free time this week and so I may not have time to get it on and finish the map... we'll see

dubtek hasnt updated the group buy on the other forum. he said an update was due on friday just gone, but hasnt posted yet. will let you know as soon as he posts up

High CO = faulty CAT

Lambda OK means mixture is OK

If mixture was rich then CAT would run hotter (sometime they even glow red when very rich) but should always reduce CO to near zero.

Edited 14 February, 201016 yr by xman

You, and the MOT garage may well be right xman.

Took the car in today having removed the re-map, CO levels are the same as they were a few days back.

Out of ideas now so am progressing on the assumption that it's a faulty cat.

Not turning out to be a good month, as I've already forked out for 4 new Vredesteins, and earlier on today put a new Pipe Werx downpipe and sports cat on the credit card. Had a few options, including getting a new CAT welded into the Piper downpipe, but this seems the way to go.

Price wise, it was a toss up whether to get a new performance down pipe and CAT or just stick a new OEM exhaust on, which ultimately would probably see me putting it back to standard and selling - not quite there yet.

Sy - memory tells me you have a Pipe werx downpipe mated to a Piper cat back - did it go together ok, only I'm booked in at JKM next tuesday and don't want them to run into trouble fitting the new downpipe....??

You, and the MOT garage may well be right xman.

Took the car in today having removed the re-map, CO levels are the same as they were a few days back.

Out of ideas now so am progressing on the assumption that it's a faulty cat.

Not turning out to be a good month, as I've already forked out for 4 new Vredesteins, and earlier on today put a new Pipe Werx downpipe and sports cat on the credit card. Had a few options, including getting a new CAT welded into the Piper downpipe, but this seems the way to go.

Price wise, it was a toss up whether to get a new performance down pipe and CAT or just stick a new OEM exhaust on, which ultimately would probably see me putting it back to standard and selling - not quite there yet.

Sy - memory tells me you have a Pipe werx downpipe mated to a Piper cat back - did it go together ok, only I'm booked in at JKM next tuesday and don't want them to run into trouble fitting the new downpipe....??

mate thats pump then. must be a ****e cat on the exhaust then i reckon.

garage never nmentioned any issues to me mate, so im gussing ity was fine. he only took 35 minutes to change the cat back to the piper and mate it to the pipewerx DP. be prepared for it to be loud?? my missus

now hates my car lol. whilst your credit card is out you should get rid of that bluefin for some real mappage lol.

i bought my car sept 2007, so will i require my first MOT this september?? ive always traded in before this point

Thanks mate - fingers crossed it will be a straight forward swap over. Not sure if I'll get a different sound or not - irrelevant really as the noise from the Piper back box will drown it out

I was considering getting another map recently - had some money mentally earmarked for a Columbus but not committed to that yet - I even got as far as getting a quote off Ben before having to shell out for all this stuff.

Yep your MOT will be coming up - take my advice and get it in with plenty of time to right any wrongs.

Thanks mate - fingers crossed it will be a straight forward swap over. Not sure if I'll get a different sound or not - irrelevant really as the noise from the Piper back box will drown it out

I was considering getting another map recently - had some money mentally earmarked for a Columbus but not committed to that yet - I even got as far as getting a quote off Ben before having to shell out for all this stuff.

Yep your MOT will be coming up - take my advice and get it in with plenty of time to right any wrongs.

im selling up so look out for sys big sale bonanza.

i was going to k04 it or hybrid maybe, but then id be chcking another 4K @ the cra then maybe a diff etc so realistically anpther 5K. not sure it would be worth it when coming to sell the car at a later date.

Ive got a 4wd rally car itch that needs scratching soi might look into suburu or evo. not in any rush though. I have only been driving 120-150 mile a month anyway Il just cycle to work instead?

dubtek hasnt updated the group buy on the other forum. he said an update was due on friday just gone, but hasnt posted yet. will let you know as soon as he posts up

I believe they were dispatched on Tuesday via FedEx

Sy - memory tells me you have a Pipe werx downpipe mated to a Piper cat back - did it go together ok, only I'm booked in at JKM next tuesday and don't want them to run into trouble fitting the new downpipe....??

Pipewerx is a 3" dp which reduces to 2.5" for the last 4 or 5 inches and allows it to mate with the stock cat-back. I believe (but could be wrong) that the Piper is 2.5" also and it would therefore be a simple straight connection using the existing stock joining sleeve

Good luck and be sure to let us know how you get on!

Ta Mucki - from the looks of the Piper website the cat back is indeed 2.5 inch - I'm sure JKM will sort it out, they've managed to fit every second hand part I've thrown at them so far with not one glitch

Sy - I've had similar thoughts recently, I basically want something around 300bhp which isn't trying too hard to produce that - Scooby or Evo is an obvious choice and you could pick up a decent one for the price of your car there or there abouts. M3 is an outside contender too but less practical.

I'm doing 400 miles a week at the moment though, and I honestly couldn't live with one - I know the interior of the VRS is no palace but it is a far nicer place to spend time than in one of the rally hooligans. I couple of my friends have had STI's and while they were excellent when giving it the beans, when trundling around stuck behind traffic as you do for the majority of the time, they're pretty boring.

I'd love something with a K04 in it, but am already tired of the wheelspin in my VRS - the ideal car for me would be an S3 with a stage 1 map I think.

I'm sure I read on another forum that Stu has chopped in his white S3 for a brand spanking new one - the swine.

Need a better job

Had my new Pipewerx downpipe fitted today, swapped over with my Piper - car then sailed through the MOT, so the CAT was indeed the culprit.

Now £600 lighter

Thanks for the input folks.