Welcome to the world of Saab ! Register
Results 1 to 5 of 5
  1. #1

    Join Date
    04 Jan 2018
    Location
    DFW Texas
    Posts
    3
    Saab(s)
    2005 9-3 2.0t
    Thumbs Up:   0

    New owner catalytic converter problems?

    Hello, all. My first post. I have a 2005 9-3 2.0t 5-speed convertible and it bucks wildly (feels like detonation or fuel cut) when it comes into boost. It revs real slow, no power, and when held at 2k rpms nothing is coming out the tailpipe, which is black and covered in soot. It has the codes p0300 and p0420. So I figured one, or both, of the cats is/are clogged. So I climbed underneath the vehicle and unbolted the exhaust from the precat (or front cat) and proceeded to take it for a test drive. While driving, with just running the front cat it revs a lot faster and doesn't buck at all. But it does misfire badly once really getting on it under a load. Like it's blowing out the spark, but doesn't buck like detonation. So, I believe it needs new plugs and a rear cat, but I just want to make doubly sure from the experts here.

    I own two Chrysler Conquest TSi's that are highly modified, so turbo cars are nothing new to me.

    Any help would be greatly appreciated and I thank y'all in advance.

    0 Not allowed!

  2. #2
    Saab Owner Digger's Avatar
    Join Date
    28 Oct 2016
    Location
    Minneapolis Minnesota
    Posts
    781
    Saab(s)
    2006 9-3 2.0t SportCombi
    Thumbs Up:   124
    Sounds like a bad CAT to me and being an OBD2 system part of your trouble driving with the main cat loose is the O2 sensor readings causing improper fueling. You probably will need plugs, but keep in mind that honeycomb biscuits don't plug up, break up, or melt down on their own, there is always a direct cause that needs to be found and resolved, or you can expect this to happen again. Usually a sensor O2 for most common sensor cause, other common causes are leaky injectors, fuel pressure regulators and bad PCV's. Bad gas can do this too.

    Pull your main cat completely loose and look down the pipe, if you find black / melted chunks bang your fist down the rest of the pipe to the tail spout, it rattles inside plan on pulling the entire pipe and if you can shake out all the chunks do that. If you can't, plan on replacing everything back. Beyond the irritating rattle you will have if you don't, the chunk causing the sound can get sideways in the pipe and you suddenly get as plugged up as if someone stuffed a potato up the snout.

    Pre CAT's seldom plug, but if you have an inspection camera handy, use it to take a look, good honeycomb on the output side almost always means that it's good to the input side.

    0 Not allowed!

  3. #3

    Join Date
    04 Jan 2018
    Location
    DFW Texas
    Posts
    3
    Saab(s)
    2005 9-3 2.0t
    Thumbs Up:   0
    Thanks for the reply, man. The precat seems to flow fairly well, and when tapped with a small hammer, lightly, the sound resonates. When I tap the rear cat it sounds like a dull thud for the first three quarters of it's body. (From front to rear) that's what led me to checking the second cat the way I did. If the car would have acted the same while only running the precat, I would have gutted it and then went for another test drive. The rear cat has been ordered and should be here in a couple of days. After I install it I'll post back up with how it performs then.

    Thanks again.

    0 Not allowed!

  4. #4
    Saab Owner Digger's Avatar
    Join Date
    28 Oct 2016
    Location
    Minneapolis Minnesota
    Posts
    781
    Saab(s)
    2006 9-3 2.0t SportCombi
    Thumbs Up:   124
    Don't throw the old CAT away, whatever is left of the biscuit is worth some bucks, how many depends on how much material is still inside. When you go to the recycler take the box and receipt for the new CAT with to prove what you're bringing in isn't stolen.
    Good time to clean the throttle body while you are waiting on the new CAT, while you have it off for cleaning, stuff a fist sized wad of paper towel into the intake manifold and pull it back out. This won't tell you if your PCV is good because there is always some oily residue inside, but if it comes out dripping of oil you will know it darn sure isn't.
    Always a good idea to replace O2 sensors with the CAT, I know it's an extra expense, but if you can afford the parts today, it's not worth the risk of buying another CAT tomorrow.

    0 Not allowed!

  5. #5

    Join Date
    04 Jan 2018
    Location
    DFW Texas
    Posts
    3
    Saab(s)
    2005 9-3 2.0t
    Thumbs Up:   0
    Yessir. I have an AEM Uego to go in the precat and I'm picking up the second O2 when I grab some NGKs. Thanks again.

    0 Not allowed!

 

 

Similar Threads

  1. Proud First-Time Saab owner... with a few problems.
    By weathersaab in forum Saab 9-3 (2003-2014)
    Replies: 4
    Last Post: 01 May 2015, 00:11
  2. ** New Saab Owner. Few questions/problems. Please help!! **
    By B00ST2nR in forum Saab 9-3 (2003-2014)
    Replies: 2
    Last Post: 03 April 2015, 00:56
  3. New Saab owner with a few problems
    By Enforcer in forum Saab 9-3 (2003-2014)
    Replies: 5
    Last Post: 19 December 2014, 13:05
  4. Catalyctic converter bad?
    By sacady in forum Saab 9-5 (1998-2009)
    Replies: 3
    Last Post: 13 June 2012, 05:15
  5. Bypass Catalytic Converter
    By Altumdreams in forum Saab 900 (1979-1994)
    Replies: 8
    Last Post: 16 January 2012, 21:20

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •  
All times are GMT. The time now is 15:58.
Powered by vBulletin® Version 4.2.5
Copyright © 2018 vBulletin Solutions Inc. All rights reserved.