Petrol Diagnostics

Post a Response

Audi A3 1.8 T AUM 2001 - Emissions failure #

Posted by Les Smith on July 31, 2010, 4:53 pm

Year of Manufacture *: 2001 wauzzz84421009830
Engine Size and Code *: 1800 TURBO engine code AUM
( Optional ) Scanner Used: solus

Hi All.Your thoughts would be appreciated. Short history. Timing belt broke due to seized camshaft and 2nd hand engine fitted elsewhere. Off road for over a year. Failed mot and brought to me.Tick over lumpy but runs OK on road.Code read.About 10 codes, so erased. None returned. C02=12.3 O2=4.29 HC=15 CO=0.00 Lambda=1.238. Checked vac = 10 In-Hg at tick-over. 20Hg at fast idle. Compressions are all about 125.Will check my tester on good engine on Monday to make sure working ok. There had been a new timing belt fitted.No Vac leaks found.Exhaust gas tight. Checking valve timing next.Although running OK on road, do you think valve timing out could cause this fault?
Regards
Les

Re: AUDI A3 EMMISION FAIL

Posted by Pete Mutlow <iframe src='https://members5.boardhost.com/ukautotalk4/info/user=UKAT1569' width='330' height='300' border=0 style='border:none;'> on July 31, 2010, 7:12 pm, in reply to "AUDI A3 EMMISION FAIL"
Peter Mutlow

Evening Les,

With the compressions a bit low and vacuum low at idle then there is a chance the valve timing could be out. However.....I would like to see the 4 gas readings at idle and would be interested to see if O2 is reading very high indicating an air leak somewhere. This on the assumption that the emission test at idle was ok.

Regards

Pete M

Re: AUDI A3 EMMISION FAIL

Posted by les smith <iframe src='https://members5.boardhost.com/ukautotalk4/info/user=UKAT1209' width='330' height='300' border=0 style='border:none;'> on July 31, 2010, 9:03 pm, in reply to "Re: AUDI A3 EMMISION FAIL"
Leslie Smith

Pete. Would you believe I forgot to take down the readings at idle.(Auld fool)I know that at idle the lambda reading was so far out that it did not show on machine. I will take this reading on Monday. Thanks for your interest.
Les

Re: AUDI A3 EMMISION FAIL

Posted by Pete Mutlow <iframe src='https://members5.boardhost.com/ukautotalk4/info/user=UKAT1569' width='330' height='300' border=0 style='border:none;'> on July 31, 2010, 10:52 pm, in reply to "Re: AUDI A3 EMMISION FAIL"
Peter Mutlow

Hi Les,

If the lambda reading is so high and off the scale, then the O2 will be also be very high which indicates an air leak somewhere or the secondary air pump is running (if it has one). If u can't smoke it then try spraying easy start

around the likely places.

Regards

Pete M

Re: AUDI A3 EMMISION FAIL

Posted by ian slattery <iframe src='https://members5.boardhost.com/ukautotalk4/info/user=UKAT1196' width='330' height='300' border=0 style='border:none;'> on August 1, 2010, 8:22 pm, in reply to "Re: AUDI A3 EMMISION FAIL"
Ian Slattery

Is this the engine that can get a internal air leak in the dump valve in the breather system?

Re: AUDI A3 EMMISION FAIL

Posted by Patrick Heaher on August 1, 2010, 9:19 pm, in reply to "Re: AUDI A3 EMMISION FAIL"
Message modified by board administrator August 3, 2010, 3:01 pm

is the short term fuel trim up or down

Re: AUDI A3 EMMISION FAIL

Posted by les smith <iframe src='https://members5.boardhost.com/ukautotalk4/info/user=UKAT1209' width='330' height='300' border=0 style='border:none;'> on August 2, 2010, 8:30 pm, in reply to "Re: AUDI A3 EMMISION FAIL"

Thanks for you interest. Not got smoke machine but vehicle well sprayed at tickover and no change. readings at tickover are co=0.0 HC=0 02=7.79 and CO2=9.4. O2 regulation is 23.1.O2 sensor 1 closed loop but sensor 2 open. When WOT 1st sensor goes open loop for a few seconds. TCS status= no activity??? With high readings you would think there was an air leak that would be easy found. One other thing to complicate matters. I have found out when the garage fitted the engine, the head was wrong. They managed to get the correct head but to me, that means it is the wrong block. For all I know the pistons could be different.I am not spending a lot of time on this for the next few day's. Customer in no hurry and I have enough on my plate at the moment.Any thoughts? I will keep you posted.
Cheers
Les

Re: AUDI A3 EMMISION FAIL

Posted by Pete Mutlow <iframe src='https://members5.boardhost.com/ukautotalk4/info/user=UKAT1569' width='330' height='300' border=0 style='border:none;'> on August 2, 2010, 9:21 pm, in reply to "AUDI A3 EMMISION FAIL"
Peter Mutlow

Hi Les,

Can you determine if the engine balance is ok on tick-over?

What I find ironic about all this is that this car has essentially failed the MOT Emission Test because it is emitting too much oxygen!

Regards

Pete M

« Back to index

[ Petrol Diagnostics ]