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Catalytic converter is toast ??

Discussion in 'Chevy Trucks' started by ronj, Dec 23, 2005.

  1. ronj

    ronj Junior Member
    from mn
    Messages: 21

    Hey, my '87 Blazer runs fine at low rpm, but worse & worse as I gain speed. The exhaust smells funny (like sulfer, my buddy says) could this be a sign the catalytic converter is junk? 155,000 miles on it, I have replaced the exhaust twice in the last 12 years, but the converter is original. Whatcha think
     
  2. Mick

    Mick PlowSite.com Veteran
    from Maine
    Messages: 5,546

    Does it occasionally lose power going uphill? This is what my wife's Buick is doing and I'm being told it's the converter. Just once in a while so may last a long time.
     
  3. RolyF

    RolyF Junior Member
    Messages: 22

    Hi Ron. IMHO the cat is not the problem although it might get ruined by your problem. Sounds like the system might be running very rich. Is the MIL (check engine) light on? Does the temp. gauge show the engine fully warmed up? The final test to eliminate the cat is to disconnect the exhaust in front of the cat and drive at a high speed to see if the power returns to normal. If it does the problem is the cat, if not look elsewhere. Very few cats fail on their own.
     
  4. ronj

    ronj Junior Member
    from mn
    Messages: 21

    more info

    The temp gauge seems normal, the check engine light comes on occaisionally, the exhaust does smell rich (like fuel) to me. If the system is running rich what's the cure?
     
  5. Caleb55

    Caleb55 Member
    Messages: 44

    If your getting a sulfer smell, it's usually the cat that's going bad. When they become plugged over time, they can hurt vehicle performance and gas milage or your truck may just not run. That happened to a buddy's truck once. You might try replacing your O2 sensor before changing the cat though. My '95 chevy, which should have the same 350 tbi engine as your truck had the sulfer smell. I replaced the O2 sensor and the small went away. Deffinetly would be cheaper to change that then the cat.
     
  6. Detroitdan

    Detroitdan PlowSite.com Addict
    Messages: 1,937

    definitely the cat. Could also affect O2 sensor, EGR system, etcetera if you don't take care of it soon. a quick fix is to pound on it with a hammer while someone revs the engine, this will help clear out a little of the blockage. I've had to do that on a GF's Escort, got by for months like that, it would actually come to a stop and refuse to restart it was so plugged. Bang on it a bit and she'd fire right up! I have seen people take the pipe off and shove a crowbar in there to open it up. Not legal to do, but some states don't check anything that old. Your best bet is too replace it, there are aftermarket free flowing cats available now that are way cheaper than an OE cat.
     
  7. ronj

    ronj Junior Member
    from mn
    Messages: 21

    02 sensor

    yep, replaced the 02 senser already. No improvement. I pulled the converter, that thing weighs about 25 pounds ! Is that normal ? Can't see through it, or show a flashlight through it, but don't really think the passage is straight through... Sounds like sand inside when ya tip it back & forth. Wrecked my last saws-all blade trying to cut it open, that bastards tuff. Gonna wait till my neighbors sound asleep and see how it runs.
     
  8. RolyF

    RolyF Junior Member
    Messages: 22

    You really need to find out what is turning on the check engine light. Just tossing a cat on may only be a temporary fix because you need to find out what killed the cat in the first place. There are three main causes of cat failure. The first and biggest is due to melt down from a rich mixture. The second is breaking up and subsequent plugging, and the last we don't see much anymore-lead contamination. Other things such as silicone will damage a cat but not usually so it plugs.
    And don't forget, we have no hard evidence yet that it is the cat which is causing the problem.
    Diagnose first, or you may end up spending far more than you have to. And don't leave the cat off. It's there for a reason, and most states will fail you for lack of emissions equipment.
     
  9. ronj

    ronj Junior Member
    from mn
    Messages: 21

    whats a rich mixture & what's the remedy ?

    The only trouble code (with engine not running) when this started was "45"
    There was no code with the engine running, the light flashed quick continuously... after replacing the 02 sensor the trouble code stayed the same, I kind of bought the cat theory, thinking it was semi-clogged at best (with the funky smell & poor performance) causing the 02 sensor to keep throwing that code. I'm not familiar with the "rich mixture" stuff can ya educate me on settings/trouble shooting etc ? Thanks.
     
  10. Caleb55

    Caleb55 Member
    Messages: 44

    The cat will be real heavy. And it will also sound like there is sand in there.
     
  11. derekbroerse

    derekbroerse 2000 Club Member
    Messages: 2,377

    The sulphur smell is proof that the cat is WORKING, it is just being overloaded with way too much fuel. Definately need to fix the problem quickly before it fouls the new cat too.... which BTW if it works it will smell like sulphur as well. Most aftermarket cats are not as effective as OEM's... but are typically much lighter and smaller, and often flow better (due to less internal matter).

    Yes, it should be heavy. There are two types--pellet and catacomb style. The pellets are the ones that rattle like sand. The catacomb style will not. These things are full of precious metals (platinum amongst them) and that is why they are so expensive. You can sell the scrap ones at the local metal dealer usually. I think the bodies are usually stainless steel (under the heat shields).

    I don't have a code book handy at the moment, but someone on here should be able to tell you what it means.
     
  12. ronj

    ronj Junior Member
    from mn
    Messages: 21

    Dead end ??

    Nobody has a clue how to deal with a "rich mixture" ??
     
  13. Robhollar

    Robhollar Senior Member
    Messages: 766

    CODE 45 O2 - Rich Exhaust Check the evaporative charcoal canister and it's components for the presence of fuel. Replace the O2 Sensor.


    Do you have a post cat o2 sensor or just a pre cat????

    If I was you id be lookin real hard at the egr and related parts. You may also have some sort of vac leak also causing the motor to over compensate and rich up the mixture. The easyest way to find a leak is to spray the lines using a can of carb cleaner....Rob
     
    Last edited: Dec 26, 2005
  14. ronj

    ronj Junior Member
    from mn
    Messages: 21

    Thanks Robhollar

    02 is pre-cat
     
  15. hudie3

    hudie3 Junior Member
    Messages: 19

    my 94 k1500 was doing the same thing, running rich and toasting the cat. took it to a garage and they put a scan tool on it and the scan tool would not even register anything with the truck. turns out i had a bad computer, i took a chance and replaced it and havent had any problems since.

    just a thought :drinkup:
     
  16. ronj

    ronj Junior Member
    from mn
    Messages: 21

    Yikes !!

    Where's the computer located & what's the goin rate at the junk yard ?? payup
     
  17. PlowingHD

    PlowingHD Junior Member
    Messages: 26

    you need to get someone with a scanner to see what the O2 data is. when the engine is warmed up, it should oscillate from 0 to 1 volt 0 meaning lean, lots of oxyegn content, 1 volt meaning rich, no oxyegn content. If it is stuck around 900 mv to 1 volt, you need to see why and how the engine is getting additional fuel. my diagnosis by computer would be that the coolant temp sensor is out of range, telling the ECM to add fuel. see lots of problems with the harness end going into the CTS. By the way, it is next to the thermostat housing.
     
  18. ronj

    ronj Junior Member
    from mn
    Messages: 21

    Coolant temp sensor

    I replaced the coolant temp sensor, when it started acting funny. Along with a new 02 sensor,coil & control module
     
  19. Robhollar

    Robhollar Senior Member
    Messages: 766

    Can you put the old coolant temp sensor back in???
     
  20. ronj

    ronj Junior Member
    from mn
    Messages: 21

    Old coolant sensor

    I threw it out.