What are the symptoms of a blocked cat?

Thread in 'Technical Questions' started by dynamodav, Nov 25, 2007.

  1. dynamodav

    dynamodav Member

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    Im having a bit of trouble with my s14a, lumpy idle, lost power, surging while driving (literally shunting the car, holding the revs, then taking off with power, while driving it can sometimes shake the car quite severely).

    Im thinking its the cat, because it smelt like a fart after giving the car some, usually indicates a cat on the way out. What would you expect the symptoms to be with a blocked cat?
     
  2. THICK SOUP

    THICK SOUP Active Member

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    If the cats totaly collapsed & blocked the exhaust then the engine would'nt rev (it might not even run, but I've not seen one that bad) Sounds more like a ignition fault, or possible fueling problem. Try taking the exhaust off, from the down pipe back so inculding the cat, see if that makes a differance.
     
  3. jon1200

    jon1200 Active Member

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    why not take the cat out and see if its any better?
    Plus you get mooooooooooore power :)
     
  4. initial_j

    initial_j Made guy

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    take it to the vet?
     
  5. dynamodav

    dynamodav Member

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    I was going to try taking off the exhaust to see if thats any better, ive not got access to a diagnostics computer for the jap plug, only euro obd. It could be anything from the mass airflow meter, a collapsed vacuum pipe, fuelling problem, blocked cat as mentioned earlier, boost leak?? Or a combination of?? Just trying to get ideas, will look at it on the weekend coming now, just didnt want to start splashing cash without knowing what was at fault.

    Another fault is with the idle control, idles at 1000rpm, tried adjusting the idle control valve, got it lower from 1250 to 1000rpm but wouldnt go any lower. It sometimes keeps the revs higher when stopping at lights, quite irratic.

    Another question, will the car pass the MOT without a cat, whats the general consensus on the forum?? Im new here.

    Cheers
     
  6. steve_mr2turbo

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    IF your cat is blocked the downpipe and anything before it will glow red, even on tickover because the hot gasses cant escape! seen this happen before, pretty awsome sight! blockages usualy caused by exessive tow starting and not firing thus pouring fuel into the cat.
     
  7. Harlen

    Harlen Sum Yung Gai

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    Thats exactly what I thought, when I saw the thread title I thought it was a micky take :wack:

    You're best off just removing the cat and putting in a de cat pipe :) MORE PAWAZ.
     
  8. flatout

    flatout Member

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    cat went on my s14,it ran fine just no power no boost at all,cut the cat open and ripped the guts out off it:wack:,job done flying again, sounds like your AFM
     

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