possible blocked cat

  1. Newbie Joined: Nov 2010 Posts: 14
    #1
    i think i may have a blocked cat, after doing some reasearch online, jus wanted to know if anyone cud tell me some syptoms, and also if anyone has had this before and what they experienced.

    also does anyne know of any ways to check the cat without using special gear as i donr have access to anything like that, or money to go to a garage

    cheers guyss
    Jack
  2. Established Member Joined: Feb 2009 ★ West / North Yorkshire ★ Posts: 1653
    #2
    Orite Jack. What makes you think youve got a blocked cat?
  3. Saxperience Addict Joined: Oct 2008 Plymouth, Fiddling - under a two poster ramp Posts: 14064 Audi
    #3
    Thermomiter...it needs to be a solid temp from front to rear, if there is a big jump, and the rear is hotter than the front, youneed a new one.
  4. Saxperience Post Whore Joined: Aug 2009 ilkeston derbyshire Posts: 9823 C2 VTR stripped, 406hdi, clio 172
    #4
    check if there is any less pressure coming out of the tailpipe, roaring noise from inlet, rattling from cat,restricted revs are all symptoms of a duff cat, a lot of cats fail shortly after head gasket failure as water through the exhaust is a sure killer of the internals
  5. Newbie Joined: Nov 2010 Posts: 14
    #5
    well what mad me think i have a blocked cat is tht it smells very rich of petrol out of the backbox, the exhaust is fully standard but is ridiculously loud, the engine will cut out randomly, normaly at idle speed i.e. after stopping at traffic lights, the engine feels slightly restricted, and i feel my mpg is severly bad, not entirly sure what it is supposed to be but 25 quid will get me about 80 miles, and that is with driving very sensibly. cud this be a sign of something else?
  6. Established Member Joined: Feb 2009 ★ West / North Yorkshire ★ Posts: 1653
    #6
    Lambda sensor
  7. Newbie Joined: Nov 2010 Posts: 14
    #7
    cheers outrage, ill give it a check. is there anyway of checking it before replacing? cos there not cheap haha. probably just me but i cant help feel its summat more than just that?
  8. Regular Poster Joined: Oct 2010 bournemouth Posts: 272 ph2 clio 172
    #8
    Get one from the scrappy should be a lot cheaper and if it solves it buy a new one
  9. Established Member Joined: Feb 2009 ★ West / North Yorkshire ★ Posts: 1653
    #9
    Quote:
    Originally Posted by jackgardner View Post
    cheers outrage, ill give it a check. is there anyway of checking it before replacing? cos there not cheap haha. probably just me but i cant help feel its summat more than just that?
    Yeah.. i will try find my last explanation of the test cos it took me ages to write

    It might not be buddy, mine was using £20 to 100 miles and the lambda sensor sorted it. I didn't get a cheap generic one though, they will probably do more harm than good. I managed to find a brand new NTK one for another car on Ebay for a tenner and the guy only lived down the road just soldered the wires onto my saxo connector
  10. Established Member Joined: Feb 2009 ★ West / North Yorkshire ★ Posts: 1653
    #10
    I don't know how good you are with electronics but it's quite easy to test a lambda sensor.

    If you attach a multimeter to the lambda (while it is connected to the car and with it running) then you should see it alternating between 0.2 and 0.8 volts in a wave pattern.

    Connect the red test lead of the meter to Black (or Purple)
    Connect the black test lead of the meter to Grey (or Beige)
    Ignore the two white or brown wires, these are for cold start heaters.

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    ^^
    Thats the kind of thing you should see if it has got a bar readout, otherwise just look for 0.2~ to 0.8~ back to 0.2~
  11. Saxperience Addict Joined: Dec 2009 Posts: 11714 A6 Le Mans tuned/A3 TFSI tuned
    #11
    happened to me recently. The car would run slightly hotter than usual, I felt a slight loss a power right from when it got fitted. Then I had some rattling from inside the cat and ultimately the (bottom)lambda sensor indicated a fault. I also had some random cutouts.


    Got it replaced, no problem since.
  12. Newbie Joined: Nov 2010 Posts: 14
    #12
    ah amazing, ill defo give that a try, my mate has a miltimeter i cud borrow as well. when you say you got a new sensor for another car, you mean summat tottaly not a saxo. id have thought they were vheicle specific
  13. Regular Poster Joined: Oct 2010 bournemouth Posts: 272 ph2 clio 172
    #13
    You can get univeral ones just cut and join hence all lambdas with the same amount of wires will fit
  14. Established Member Joined: Feb 2009 ★ West / North Yorkshire ★ Posts: 1653
    #14
    Quote:
    Originally Posted by jackgardner View Post
    when you say you got a new sensor for another car, you mean summat tottaly not a saxo. id have thought they were vheicle specific
    Yeah, as long as its a 4 wire one, they all do the same thing - I just got the cheapest NTK one I could find (NTK are made by the same company that make NGK spark plugs : NGK Spark Plugs :: Lambda Sensors ) but Bosch are just as good if not better

    Something like : NGK NTK LAMBDA SENSOR OZA448-E49 would do the trick, but you'd need to cut the connector off your old one and solder it to the new

    ... or this * BOSCH * LAMBDA SENSOR [LS07] 4 WIRE UNIVERSAL