HELP! 1998 A4 Avant emissions problems
10-14-2011, 07:59 AM
#1
Audiworld Junior Member
Thread Starter
Join Date: Sep 2011
Posts: 14
Likes: 0
Received 0 Likes
on
0 Posts
HELP! 1998 A4 Avant emissions problems
Late August, I bought a 1998 A4 Avant 2.8 from a small mechanic's shop speciallizing in VW/Audi. The car had 57,000 miles on it, and seemed solid (except for a mild brake pedal "thump"). Prior to him recieving the car, the cats had been stolen, so he installed new aftermarkets. Here in MA, you need to get your car inspected within a week of purchase. Towards the end of that week, the CEL came on. I had to get it inspected, so I got an "R" sticker for codes P0432 and P0422, Catalyst monitor. Brought it back to the mechanic, who replaced the sensors. After about 60 miles, (no CEL) I brought it back for inspection- the same codes came up, and they suggested I drive it some more. Took it to VT that weekend, and after about 500 miles, the CEL came back on, so I took the car back to the mechanic. This time, he said the mass air flow was dirty, so he cleaned it. CEL came back on the following day (yesterday), went out in the afternoon, and is back on again this morning. My girlfriend went through a similar problem with her 2000 Jetta VR6. Her mechanic blamed the problem on crappy gas and told her to run plus or premium. I've been running plus for the past month. I'm nearing the end of my rejection period- PLEASE HELP
10-14-2011, 10:10 PM
#4
AudiWorld Member
Join Date: Feb 2005
Location: Spokane, WA
Posts: 66
Likes: 0
Received 0 Likes
on
0 Posts
1st off. You have a 30v. Run Premium, not just Plus. You can watch the ignition retard in VAG-COM even with premium. IE..Premium really is barely enought (This on West coast where our premium is 91 Octane, If you have 93, even better). I would not run less than 91 Octane.
2nd. Did he install OBD-2 Cats? IF he installed cheap OBD-1 Cats that could be contributing. OBD-2 Cats have a second stage. Also could be the cats in the Downpipe maybe.
Did the mechanic replace all the sensors? Or just the fronts or backs? Your car has a total of 4. 2 per cyl bank.
2nd. Did he install OBD-2 Cats? IF he installed cheap OBD-1 Cats that could be contributing. OBD-2 Cats have a second stage. Also could be the cats in the Downpipe maybe.
Did the mechanic replace all the sensors? Or just the fronts or backs? Your car has a total of 4. 2 per cyl bank.
10-15-2011, 03:29 AM
#5
No cats in the down pipe in 1998.
While I agree on your comments about fuel grade, grade has nothing to do with cat efficiency. 99 times out of 100, it's bad cats. The 100th time, it's an O2 sensor. Given that this is both sides, I'm sticking with cats as the problem.
While I agree on your comments about fuel grade, grade has nothing to do with cat efficiency. 99 times out of 100, it's bad cats. The 100th time, it's an O2 sensor. Given that this is both sides, I'm sticking with cats as the problem.
Thread
Thread Starter
Forum
Replies
Last Post