Mot

[lawser]

Ok, Just back from MOT with four failure points, 3, i can fix no probs...The 4th, exhaust emission fast idle test failure not too sure about.
On the 1st test CO: value actual was 0.490 % instead of 0.300 % - FAILED
LAMBDA: value actual was 1.029, has to be within 0.970 - 1.030, so just inside the acceptable tolerances - PASSED

On the 2nd test CO: value actual was 0.359 %, came down a little but still FAILED
LAMBDA: value actual was 1.073, so FAILED this time

Plugged in VCDS Lite & came up with no fault codes whatsoever.......:1zhelp:

I don't think there can be much wrong, any ideas folks ?

[fourringsrus]

A cat failing?

[zollaf]

what engine are we on about, and what year ?

[scotty33]

You can test the lambda sensors with a digital multimeter:

http://www.12v.org/maintenance/repairs/o2sens.php

May be worth checking the coolant temp sender for the ECU?:

http://www.12v.org/maintenance/repairs/ect.php

Both items can be out of spec but not 'failed' so would not show a fault code

[lawser]

Thanks guys, previous owner put new exhaust system on in Jan 2009, @ £520 i would hope the cat hadn't failed already :mad:
I will test the sensors tonight....Thanks.
Going back to the emissions would it be worth adding some sort of fuel additive before puting through the test again ?
It's an 1995, ABC 2.6, V6 auto, engine,

cheers,

[fourringsrus]

Are you sure the £520 included a new cat though, I was quoted £500 for a system without a cat last summer, also '95 abc v6
As it turned out I only needed a cat and found a nearly new one on a wreck,£40 lovely' and though my car is not running at it's best, it passed the mot clear just 2 weeks ago

Stuart

[zollaf]

i would give it a dose of forte petrol treatment, then drive it like you stole it for at least 10 miles, then get it retested while it is still nice and hot. if that doesnt do the trick, and there are no fault codes logged, and the airfilter, plugs and oil are all new, then it may well be the cat. as stuart has said, the exhaust may not have included a new cat, or it might be a sports cat that doesnt work very well.

[lawser]

Point taken....Just assumed that it would have been a complete exhaust system for that price :biglaugh:
I've gone down the route of treating the petrol & giving her a thrash before the MOT, recommended by a few folk....:beerchug:

[lawser]

Thanks folks....Passed the MOT no problem now :D

[fourringsrus]

Well done, it's a weight off your mind when they clear these hurdles

[lawser]

Ok MOT time again, after almost a year of troublefree motoring i have an MOT failure on emissions once again......Tried the fuel additives but still the CO reading is 0.50 on fast idle & on second fast idle it reads 0.52, every other test is a pass.
Cat or oxygen sensors ?

[fourringsrus]

Lawser, hi there buddy, I have just had almost exactly the same c/o reading and fail on my latest '95 abc coupe.
If you look for my thread a couple of weeks ago, or thereabouts you can compare details, I think the thread in the coupe section was titled something like ABC Cat.
First test was on a trailor to the test station and was advised to thrash the car on the return for retest, still failed but slightly cleaner.
Went home and swapped coolant sensor and sender from my other abc which had passed just two days before and I also swapped all 6 plugs, still no good.
Sought more advice from the forum gang and decided the cat may well be the culpret.
Collected the new cat from Eurocarparts the following morning and fitted ,returned to mot station, presto, zero reading apparently.
New cat cost just under £100 but I had to get a weld repaired before it could be fitted, had amoan and got £30 refund.
Make sure that when you order the cat that you stress that you will need the fitting kit of gaskets/bolts etc at around £5.
I was hesitant to order a cat at first because of the cost but it turned out to be the issue after all.
I'll have a look at my previous thread to confirm my readings
Good luck

Stuart

[fourringsrus]

Lawser take a peek at my thread " ABC V6 Cat please help " dated 30/4/11. Audi Coupe section
There are about 4 pages of what I went through but as you'll see we got there in the end
Your c/o figures are almost exactly the same as mine but have a read and hopefully you'll agree that it looks like you cat on its' last legs

Stuart

[lawser]

Thanks Stuart, yeah i think i remember the tester last year mentioning the CAT....what you have gone through kind of reinforces that fact. Might as well start with the CAT, thanks for the heads up with Eurocarparts,

cheers,

Paul

[fourringsrus]

In relation to Europarts, the cat did not turn up on the day they said it would, it did not come with fitting kit and to cap it all the weld around the neck into the cat where the pipe enters the actual cat had about 1" of weld missing, so it would have leaked the second it was fitted.
Fortunately my local garage, and good friend of mine , spotted the missing weld when I popped in to see if he could supply me with any gaskets/clamps, he welded the pipe and off I went.
I called the supplier and had a moan and they refunded me about £30.
Good luck matey.


PS; You may fancy checking out Automotive on line for your cat, they quoted a similar figure for a cat when I was ordering a pair of new downpipes for the same car

Stuart

[lawser]

Success, another year out of the old girl yet :0)...Stuart many thanks for the cat tip, replaced the cat & she passed no bother !

[fourringsrus]

Success, another year out of the old girl yet :0)...Stuart many thanks for the cat tip, replaced the cat & she passed no bother !

Paul, that's great news,funnily enough I was about to pm you just to see how you were getting on.
Well done fella
Stuart