Question about 1998 Audi A4

1 Answer

Hi, Few days ago my Audi A4 1998, 128K done, failed MOT on high CO emissions. Somebody suggested to put Injector cleaner in fuel, and smoke free in Engine, did that, went for a spin night before and then took it for retest in the afternoon, it failed again, However the readings were slightly lower. Fail readings were: first idle test: 2558 rpm CO--limit (0.30%) reading 0.48% Second idle test:2527 rpm CO--limit (0.30%) reading 0.53% Day 2. first idle test:2720 rpm CO--limit (0.30%) reading 0.51% Second idle test:2549 rpm CO--limit (0.30%) reading 0.46% Spoke to a local garage guy, he checked that Oxygen sensor is working and needs to replace the CAT. I am not convinced, as the car runs absolutely ok, no lights fron ECU etc.. Please advice?? thanks

Posted by on

Ad

1 Answer

  • Level 2:

    An expert who has achieved level 2 by getting 100 points

    All-Star:

    An expert that got 10 achievements.

    MVP:

    An expert that got 5 achievements.

    Vice President:

    An expert whose answer got voted for 100 times.

  • Expert
  • 274 Answers

Replace cat. The mechanic was correct.

Posted on May 16, 2011

Ad

1 Suggested Answer

6ya6ya
  • 2 Answers

SOURCE:

Hi there,
Save hours of searching online or wasting money on unnecessary repairs by talking to a 6YA Expert who can help you resolve this issue over the phone in a minute or two.

Best thing about this new service is that you are never placed on hold and get to talk to real repairmen in the US.

Here's a link to this great service

Good luck!

Posted on Jan 02, 2017

Ad

Add Your Answer

Uploading: 0%

my-video-file.mp4

Complete. Click "Add" to insert your video. Add

×

Loading...
Loading...

Related Questions:

1 Answer

After warm up engine runs ruff and loss of power


Injectors need cleaning if it is a diesel
There is a buold up of contaminants in your fuel system that needs to be cleaned out

If it is a petrol engine I would be very surprised

Just add a couple of treatments of injector cleaner to a full tank of fuel and go out for a high rev blast for an horor twom that should hopefully clean it.

My old renault laguna failed emissions so I PUT 2 bottles of forte injection cleaner and went out for a 70 mile blast, it was a diesel car. I returned to the testing station within 2 hours and the black smoke had ccleard and I got the pass certificate.

Jul 09, 2015 | Cars & Trucks

1 Answer

High CO emissions. MOT failure. No codes. Runs like a dream. Fuel consumption high


check that the cat converter is not failing and blocking up the exhaust system. or not doing it,s job. replace both HO2S and O2 sensors

Apr 15, 2014 | 1999 Land Rover Range Rover

1 Answer

Hi Audi A4 1.8 T sport, X reg failed mot on high emissions Front Lambda replaced, and readings still high (running rich) any ideas please


hi this could be a few things but more than likely it is either the MAF sensor or MAP sensor, these things do roughly the same thing, but the MAP also adjusts the timing through the ECM , either one would cause this to "over fuel" and not burn correctly, the starting place would be try the MAF first as this is the common one, make sure spark plugs have been changed as this also will help, if you still get a fail, then try the MAP sensor...hope this helps good luck..

Sep 17, 2010 | 2000 Audi A4

1 Answer

99 audi a4 1.9 td red i starts perfect but has a misfire when cold and wont rev over 3000 revs and puts out a bluish white smoke but if i bring it for small drive turn it off for few mins and start it...


first check your glow plugs that they are not faulty,if faulty replace them,then get a bottle of injector cleaner and put it in your fuel take and replace your diesel filter,and also change your oil and oil filter,maybe your hydralic lifters are not preasurising when cold

Nov 19, 2009 | 1997 Audi A4

2 Answers

Hi, 2000 Landrover Freelander 1.8 petrol, failed MOT on CO emissi


check both lambda sensors for breaks in wires and for open circuit on heater side of lambda sensor on the one under the car on the second cat,failed heater element will not heat gas engough for sensor to read causing false readings , also check for slow i.a.c valve on inlet manifold.

Sep 26, 2009 | 2002 Land Rover Freelander

2 Answers

Improper fuel combustion; need to pass emissions test


Sounds like you need to replace your oxygen sensors.  If you have a four cylinder I think you only have one oxygen sensor and the six cylinder I know has 2.  You can check that out at your local parts store.  Anyway, the oxygen sensor helps the computers in your car make sure that you are getting the correct amount of fuel and air during combustion thus controlling your emissions.  I would think that if you haven't replace these in a while that is what is probably keeping you from passing your test.  Change the oxygen sensors and put a bottle of good fuel injector cleaner in a full tank of gas and you should be good to go.  I would suggest Greased Lightening fuel injector cleaner that can be purchased at Napa and O'Reilley Auto Parts.  Let me know if you have any other questions.  Thanks for an honest rating and for using FixYa!

May 24, 2009 | 1995 Ford Contour

2 Answers

Ford failed MOT on High CO emission


High CO usualy means the O2 sensors are not reading properly. Take it to a parts store that can read codes, I know Auto Zone does in my area. If it is the O2 sensor it is an easy fix but the sensors run about $50.00 each.

Apr 18, 2009 | 1995 Ford Escort

2 Answers

Volvo 850 failed MOT on emissions


It sounds like the catalytic converter is bad.

Dec 16, 2008 | 1996 Volvo 850

1 Answer

VW POLO EMISSIONS FAILED


YOU COULD TRY SOME FUEL SYSTEM CLEANER TO CLEAN ALL THE CARBON DEPOSITS OR U MAY NEED TO REPLACE LAMBADA SENSOR OR YOUR CATALYST

Sep 06, 2008 | 1998 Volkswagen Golf

2 Answers

Mot failure on emissions


make sure to smell the oil and see if it is contaminated with fuel
if it is then do an oil change and try to re test

May 27, 2008 | 1996 Toyota RAV4

Not finding what you are looking for?
1998 Audi A4 Logo

Related Topics:

485 people viewed this question

Ask a Question

Usually answered in minutes!

Top Audi Experts

Colin Stickland
Colin Stickland

Level 3 Expert

22484 Answers

Marvin
Marvin

Level 3 Expert

85020 Answers

Jonah Oneal

Level 3 Expert

14092 Answers

Are you an Audi Expert? Answer questions, earn points and help others

Answer questions

Manuals & User Guides

Loading...