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P0420

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    MAKE:suzukt
    MODEL:forenza
    YEAR:2006
    MILES:130K
    ENGINE:2.0
    DESCRIBE ISSUE.... Car throws this code cat efficency low Replaced cat and O2 Drove 2 days and code came back Any ideas or suggestions? No scanner to monitor O2 activiy
     
  2. Hey dave -
    Without knowing what the pre and post cat o2 readings the PCM is seeing I can only 'guess' a likely scenario.

    I would guess that the cat is getting some mixture it cannot clean up.
    There is a wiring problem. Maybe a defective o2 sensor. Exhaust leak. coolant or oil entering cat. Engine ECT. Really cheap replacement cat.
    Any active codes or known issues ?
    My tag line is it stock, no modifications.
    Maybe a fuel inj leaking.

    Sorry just possibilities guessing what the PCM is dealing with is a guess.
     
  3. You should be able to monitor those O2 sensor readings with a couple of simple voltmeters and long leads. Not nearly as easy as live-data, of course, but entirely "doable".

    Did you do a "smoke test" for exhaust leaks after the cat was replaced?
     
  4. Ex is clean and clear car runs like a top good fuel economy about 30 in the city. Ordered a new scanner to read O2 readings will be here friday I hope
     
  5. some info
     
  6. I think the key here is knowing if the o2 readiness monitolrs and appropriate drive cycles were done after repair of the cat and o2 sensor.
     
  7. Checking monitors will require a SCANNER -
    unfortunately a scanner is a must have these days.
    My point file and dwell tools not so much.
     
  8. OK now have scanner to monitor O2 Replaced downstream O2 as well to know all is new. Have put over 200 miles on car and code still sets. As I monitor both up and down while running they bounce up and below 500 In the old days we looked at O2 crosscounts and they seem to be functioning perfectly. But if I clear the code do a cold start and drive both stop and go and highway within 25 to 30 miles the code sets again. OK where to go from here?
     
  9. How about the leak test on the exhaust, was that ever done, using smoke or soap-solution all over?

    What frequencies are the O2 sensors "bouncing at"? A graph would be nice, but just an estimate is better than nothing.

    Have we asked where fuel trims are sitting?

    How long does it take to go into closed-loop?

    Does anybody have an FSM for this vehicle? We need to know the specific sets of conditions that can set the code.
     
  10. Dabunk, we have known each other for a while, can you plz show short and long trims.
     
  11. In principle, this should be an easy fix with live data.

     
  12. The only thing here is to understand balance of the fuel trims, the algorithm of the pcm is already set up.
     
  13. OK got time this week to get back to this. Remember I am diesel tech car tech poor. Drove car 20 miles pulled in and chr=ecked at idle short term fuel trims reading betwen 0/1/2 long term fuel trims reading a steady 2 and code p0420 had reset during the drive. Next step?? Thanks
     
  14. Hey Dave ;
    I am confused -those fuel trim readings 0/1/2 ? could you translate to what I am used to - something like STFT +2 , LTFT +2....
    Don't forget to give us ECT, IAT, B1S1 o2 voltage, then post B1S2 voltage....
    The manual I will try to get, right now pretty generic.
    "and the PCM detected the HO2S-12 and HO2S-11 signals were too similar." I know useless give me some time to get manual

    GTG
     
  15. There are some conditions in the TSB I posted above post #5 -
    still looking
     
  16. Wow, I am way late responding to this thread, completely forgot about it. Sorry.

    @dabunk, this is more and more looking like a cat problem. You say up and down stream o2s are new, still coding, right?

    When fuel trims are as you say, they are not ok, the only thing left, is either a exhaust leak or a bad cat. If your secondary o2 is not switching like it should and its new, yup, bad cat.

    Hope that helps.

    Here is a PDF anyway for you the help you along if you doubt the catalyst.
     
  17. The TSB Kev2 gave is very precise, and if you follow the above PDF, there can only be one conclusion, bad cat.

    Do you have a laser temp probe? That would help diagnose a bad cat.

    If you don't have one, they are cheap and a very essential tool for your tool box.

    Watch this video.

     
  18. OK you installed new o2 sensors ( they are not AF sensors?) and a new cat?

    the scan details are missing but I am agreeing that the cat is not getting hot enough* - how is ECT - FT's , front o2 sensor should swing (.3-.7) but rear should be fixed @.5-.7
    The cold start comment setting code has me thinking temp - ECT , overly rich, at start

    *Did I read something in TSB about cat temp...
     
  19. I'm having the same problem with a 01 acura integra 1.8, 163,000 miles. This car is running great but I have a rattle in the exhaust that sounds like marbles banging around in there. Does this mean the cat converter is shot?
     
  20. Brand new cat and O2 sensors and getting same as before the change. I am looking at monitoring engine coolant temp it seems to go cool aftr it sits for a few minutes. I followed the TSB posted and it still not pass but I am thinking it is getting to cold to pass.
     
  21. That is a very reasonable assumption. I would certainly check that out. I think you are the right track now.

    ;)
     
  22. can y0u tell us some findings ECT, FT's , the pre and post cat voltages - graphs- but that is a lot to ask.

    I have to ask - is there still a supply of OEM Suzuki parts?

    Maybe if we cannot correct the issue we will can follow Richard Petty advice " Cheat neat".
     
  23. As for this comment, if you can hear marbles in the cat, that is for sure something wrong there.
     
  24. Shot? yes, like when the guy's tell me to look for buckshot on the birds they kill.
     
  25. Got thermo installed today and now temp stays constnt while idling at 165. Tomorrow will take it out and use the TSB to see if I can get the parameters to set
     
  26. I am guessing "thermo" means ECT?

    Well if this is the case, and everything is staying constant, you got that one fixed Dabunk. I am pretty sure with all the new stuff you put on the car, we can be sure this will be a fixed thread.

    Good on you.;):bat:
     
  27. Well some improvement but not solved. With new thermostat ECT stays at 195 F constantly. So took it for a drive per the TSB. Finally got the Cat readiness test to pass but on driving home the CEL came back on with the P0420 cude again. Tomorrow will have to take it for another drive after I clear the code and monitor all the other parameters in the TSB. More fun
     
  28. Did miss a post - what are the o2 readings looking like
    Pre cat - and hi or rich readings?
    post cat - fixed and at what?
     
  29. pre cat bouncing from -1 to 2 at idle post cat 4 to 5 at idle ect 195
     
  30. The pre cat is showing - negative voltage? or is it fixed @.1 to .2 that would be a problem if that low..

    should be switching @ .3 to .8 volts
     
  31. God damn it, I hate those P0420 codes
     
  32. Something is not working here.

    @dabunk, you have pretty much the best minds working for your solution, and you have stated that everything is new, have a live data capable scanner etc.

    I don't want to be the a hole here. But something is eluding you right now.
     
  33. @ this point, I am suspecting a bad ECU or an exhaust leak or you missed a bad wiring harness. Something like that would be very probable.
     
  34. As I say often here, go sherlock holmes on this car.

    when you have eliminated the impossible, whatever remains, however improbable, must be the truth?
     
  35. I don't know if I posted this or not, but just to be sure, here it is anyway again.
     
  36. Pay specific attention to this copy paste.

    Diagnostic Aids
    The catalyst test may abort due to a change in the engine load. Do not change the engine load (i.e. A/C, coolant fan, heater motor) while a catalyst test is in progress. An intermittent problem may be caused by a poor connection, rubbed-through wire insulation, or a wire that is broken inside the insulation. Any circuitry, that is suspected as causing the intermittent complaint, should be thoroughly checked for the following conditions: - Backed-out terminals - Improper mating - Broken locks - Improperly formed - Damaged terminals - Poor terminal-to-wire connection
     
  37. I once chased an elusive code like that on one of those suzuki's, it ended up being a bad connection to the ECM/ECU.

    Be sure to have a good multi meter with good piggy back leads. That is where the most techs f up. They probe with test lights, fat leads, or fat hands.

    Once I found the problem, the pins were so rounded, I could reasonably say some one probed that before me.

    So @ dabunk, utmost respect, your a wrench, but I guess you have to go back to basics on this car.

    I am very hopeful my advice did not piss you off, on the contrary, us wrenches need to stick together.
     
  38. I will be wheels down in schefferville on the 28th, I will still follow this thread until it's conclusion.;)
     
  39. Thanks nothing p--sses me off most times have found a separate pair of eyes/ears finds the difference. I am trying to learn how to post a live feed of sensors. I bought an Autel scanner which can record and save now need to find out how to get it onto the disk and upload to this site. Please bear with me but keep the comments going!!
     
  40. Hey Dave - I cant believe we are still battling this cat issue - maybe time to regroup.

    A 2006 forenza - this is the beer can looking Catalytic Converter in the exhaust down pipe at engine?
    The emissions are NOT California type?
    - - The size of that cat looks inadequate to start - well that's academic it is what it is.
    I assume the cat and sensors were NOT OEM but were aftermarket?
    There are NO other codes, no exhaust leaks, rest of exhaust is there - resonator and muffler not oversized piping...?
    Engine data -
    The fuel trims are ok? ECT is good, nothing red flag obvious?
    and we are getting the o2 readings together for us to look at - correct?
     
  41. Correct on all counts cat is attached yo ex manifold outlet O2 is in manifold and pipe after cat no leaks rest of system tight and stock. Cat an O2 are all aftermarket but all same results as with stock parts. No California ex single cat system. ECT is good now that I replaced the thermostat. No other codes ever present. Fuel trims look in spec to me but want to record while running and post here for you guys to look at.
     
  42. Is it possible for a slight head gasket leak to cause this code? Just noticed overflow tank low, pressure tested no external leaks so considering if one is causing the other?
     
  43. For the head gasket YES it would be a factor as the coolant would contaminate the sensors.... and then we get bad readings....
     
  44. OK this is going backburner until I can get around to replacing the headgasket. Thanks guys!!
     
  45. Are you going to do a "block test" first, using the dye that is sensitive to combustion products in the coolant?
     
  46. Yes did that first off. Thanks