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Thread: Cat or lambda ?

  1. #11
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    Hum, not sure about logging. It's got the hole for the flight recorder function button but no button fitted so would have to run with the PC connected. Will have a look.

    that last bit is odd, I thought the wide and would do all the trimming of fuel and the downstream was just to tell if the cat was working.
    2014 Polo 1.0
    2002 Polo 9N 1.2 AZQ, Petrol

  2. #12
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    Well finally had a few moments to myself to have another fiddle.

    bit confused though. Using standard obd, the long term fuel trim is showing up as -12%. The autocom when set to the Simons 3pe shows block 32 as -12% and 0% at idle. The confusion is, the Rosstech page has block 32 as trim at idle and trim at load, but the explanation of trims states block 32 as additive and multiplier.

    either way, would I be right in suspecting that my trim should be nowhere near -12% and might indicate an injector passing a bit much or a fuel pressure problem ?

    2014 Polo 1.0
    2002 Polo 9N 1.2 AZQ, Petrol

  3. #13
    Administrator Keithuk's Avatar
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    2010 Golf GTD (170) CBBB, 5 Door, Shadow Blue (P6/D5Q), Transmission Code: KXZ, Flat Tyre Indicator, Basic Protection Pack + VCDS.


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  5. #14
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    Thanks, usefull

    so my long term idle fuel trim is -12% which can't be good. Just checked fuel pressure and it's spot on at 3 bar. Obviously it's not an air leak (maybe it needs one !)

    the car does use more fuel than it should, and the exhaust smells rich. So things to check? MAF ?
    2014 Polo 1.0
    2002 Polo 9N 1.2 AZQ, Petrol

  6. #15
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    No MAF on an AZQ, MAP sensor only.
    My car: 2003 Polo 1.4 BBY, Petrol
    Good Lady's: 2005 Mk1 Skoda Fabia 1.2, AZQ

  7. #16
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    Anyone know the max negative value for long term idle trim ?

    if it can go lower than 12 then it's just compensating OK.
    2014 Polo 1.0
    2002 Polo 9N 1.2 AZQ, Petrol

  8. #17
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    Click image for larger version. 

Name:	Fuel trims.png 
Views:	9 
Size:	32.6 KB 
ID:	5865

    This was a log of my journey home yesterday in the missus's AZQ-engine Fabia. Time in seconds on the x-axis. Click to enlarge.
    Blue trace is first field of group 32, red trace is the second. Not sure how much it helps you, but AFAIK her engine is healthy despite 153k on the clock.
    My car: 2003 Polo 1.4 BBY, Petrol
    Good Lady's: 2005 Mk1 Skoda Fabia 1.2, AZQ

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  10. #18
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    Interesting. Doesent seem to trim the mixture back anywhere as far as much. I wonder if I have a passing injector.

    i did the cam chain this year so it's possible I didn't put some thing back together properly, but it's running really well otherwise and the cam timing is spot on.

    only thing I noticed is a rich smelling exhaust, hence investigation.

    dont really want to shell out on a cat for a car only worth <200 but it's been in the family for 10 years and I've always managed to fix every fault so far, so it's become a challenge.
    2014 Polo 1.0
    2002 Polo 9N 1.2 AZQ, Petrol

  11. #19
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    Interesting. Doesent seem to trim the mixture back anyway as far as much. I wonder if I have a passing injector.

    i did the cam chain this year so it's possible I didn't put some thing back together properly, but it's running really well otherwise and the cam timing is spot on.

    only thing I noticed is a rich smelling exhaust, hence investigation.

    dont really want to shell out on a cat for a car only worth <200 but it's been in the family for 10 years and I've always managed to fix every fault so far, so it's become a challenge.
    2014 Polo 1.0
    2002 Polo 9N 1.2 AZQ, Petrol

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