Results 1 to 17 of 17

Thread: Emissions

  1. #1
    Member sx rider's Avatar
    Join Date
    Apr 2008
    Location
    West Sussex
    Posts
    2,970
    Rides
    0

    Emissions

    Hey guys,

    I had my emissions tested today but it didn’t pass, wasn’t a mot though, had a friendly pass in sept 19 but he said the lambda was probably causing an emissions issue. Failed with a new bosch lambda fitted plus oil, oil filter and fuel filter change.

    I’m not clued up on what the numbers from today mean, but I’ll post them up in case anyone can help? Is the lambda reading good?



    Here’s the mot from September



    I suppose if the lambda is working it rules that out, I put in a new sports cat in Aug 19 so it’s not that.

    Will check plugs, which are a couple of years old now so might be them, boost leaks, earth from lambda I’ve read might be a cause, engine temperature sensor/s? I’ll clean the afm too. Maybe the Apexi no clean needs a clean?

    Anything else I’ve missed? Would good to know if anything can be ruled out from above if I’m talking s**t Maybe some are lean symptoms I don’t know.

    Could not using the car since October 19 have anything to do with it? Done about 80 miles before today’s test. Does it need to clear its throat a bit haha?
    Last edited by sx rider; 13-05-2020 at 20:15.

  2. #2
    Guest speedingmofa's Avatar
    Join Date
    Nov 2012
    Location
    the Netherlands
    Posts
    608
    Rides
    0
    Seems your CO is slightly higher than what it's supposed to be. In such a case, having the cat proper hot would help. Notice it did pass in the 2nd fast idle test if you check the numbers

    And a sports cat may just not be 'good enough' to get lower numbers, specially one with a low cell per square inch. Iirc, a 400 or higher cell would pass, while a cheap 200-300 cell would struggle

  3. #3
    Member sx rider's Avatar
    Join Date
    Apr 2008
    Location
    West Sussex
    Posts
    2,970
    Rides
    0
    Ah right ok so it’s not massively overfueling / running rich then?

    The cat is manga flow not sure if anything about 200 cell is considered high flow though is it?

  4. #4
    Guest speedingmofa's Avatar
    Join Date
    Nov 2012
    Location
    the Netherlands
    Posts
    608
    Rides
    0
    Quote Originally Posted by sx rider View Post
    Ah right ok so it’s not massively overfueling / running rich then?

    The cat is manga flow not sure if anything about 200 cell is considered high flow though is it?
    At that point, it's running lean. Lambda over 1 is lean, under is rich. Can't say anything about the car running lean/rich in general, as the MOT test is done without any load. It's much more crucial to run richer when the engine is under load.
    What the CO is saying is that it seems the cat is unable to convert all of the particles into "safe" particles. Any sports cat up to 400, is still considered a high flow unit. OEM is around 700-800 or so?

  5. #5
    Member sx rider's Avatar
    Join Date
    Apr 2008
    Location
    West Sussex
    Posts
    2,970
    Rides
    0
    Ah right ok, damn I didn’t know 200 cell wasn’t so good.

    When it was mot’d it had the standard cat and didn’t pass either

  6. #6
    Guest
    Join Date
    Dec 2003
    Location
    Nottinghamshire
    Posts
    1,128
    Rides
    0
    Quote Originally Posted by sx rider View Post
    Hey guys,

    I had my emissions tested today but it didn’t pass, wasn’t a mot though, had a friendly pass in sept 19 but he said the lambda was probably causing an emissions issue. Failed with a new bosch lambda fitted plus oil, oil filter and fuel filter change.

    I’m not clued up on what the numbers from today mean, but I’ll post them up in case anyone can help? Is the lambda reading good?



    Here’s the mot from September



    I suppose if the lambda is working it rules that out, I put in a new sports cat in Aug 19 so it’s not that.

    Will check plugs, which are a couple of years old now so might be them, boost leaks, earth from lambda I’ve read might be a cause, engine temperature sensor/s? I’ll clean the afm too. Maybe the Apexi no clean needs a clean?

    Anything else I’ve missed? Would good to know if anything can be ruled out from above if I’m talking s**t Maybe some are lean symptoms I don’t know.

    Could not using the car since October 19 have anything to do with it? Done about 80 miles before today’s test. Does it need to clear its throat a bit haha?

    Be cheaper to take it somewhere else, my s14a doesn't have a CAT it has never failed a MOT in the five years I have owned it.

    What sort of bell end fails a twenty year old car on emissions?

  7. #7
    Member sx rider's Avatar
    Join Date
    Apr 2008
    Location
    West Sussex
    Posts
    2,970
    Rides
    0
    Passing the mot isn’t the issue, it’s the cause of the high emissions I wanted to get to the bottom of, just make to sure she’s running sweet

  8. #8
    Guest hooky's Avatar
    Join Date
    Apr 2011
    Location
    melksham
    Posts
    950
    Rides
    0
    Quote Originally Posted by sx rider View Post
    Passing the mot isn’t the issue, it’s the cause of the high emissions I wanted to get to the bottom of, just make to sure she’s running sweet
    The 'HC' is the Hydrocarbon count, which basically means the amount of Raw/unburnt fuel in the exhaust gases, As yours are within limits (as is the lambda) i'd say the engine is running fine, but as others have suggested, the CAT is under-performing so its not scrubbing out the CO (carbon Monoxide).

  9. #9
    Member sx rider's Avatar
    Join Date
    Apr 2008
    Location
    West Sussex
    Posts
    2,970
    Rides
    0
    Quote Originally Posted by hooky View Post
    The 'HC' is the Hydrocarbon count, which basically means the amount of Raw/unburnt fuel in the exhaust gases, As yours are within limits (as is the lambda) i'd say the engine is running fine, but as others have suggested, the CAT is under-performing so its not scrubbing out the CO (carbon Monoxide).
    Ok cool, this is good news! Thanks for the info, most appreciated. Next time
    I’ll ensure the cat is hot and see how it goes, I didn’t know 400 cell would be classed as high
    flow so I might swap out the 200 cell if not

  10. #10
    Guest
    Join Date
    Mar 2011
    Location
    Longfield, Kent
    Posts
    1,419
    Rides
    0
    Quote Originally Posted by sx rider View Post
    Ok cool, this is good news! Thanks for the info, most appreciated. Next time
    I’ll ensure the cat is hot and see how it goes, I didn’t know 400 cell would be classed as high
    flow so I might swap out the 200 cell if not
    I've passed with a strict MoT tester on my 1994 Stage 1a S14 Silvia without a problem and it has a Magnaflow 200 cell sports cat. Judging by the difference between the first and second fast idle tests, I'd say that the cat wasn't up to temperature on the first run.
    I had a similar thing with my old saab daily where the pre cat was failing/partially melted, could be worth checking to make sure that all is well there.

  11. #11
    Member sx rider's Avatar
    Join Date
    Apr 2008
    Location
    West Sussex
    Posts
    2,970
    Rides
    0
    Quote Originally Posted by Mike41288 View Post
    I've passed with a strict MoT tester on my 1994 Stage 1a S14 Silvia without a problem and it has a Magnaflow 200 cell sports cat. Judging by the difference between the first and second fast idle tests, I'd say that the cat wasn't up to temperature on the first run.
    I had a similar thing with my old saab daily where the pre cat was failing/partially melted, could be worth checking to make sure that all is well there.
    Ah cool, thanks for letting me know, good to hear you pass with the same cat My precat has been deleted so being up to temp sounds like the way forward

  12. #12
    Guest R3K1355's Avatar
    Join Date
    Nov 2006
    Location
    Yorkshire
    Posts
    12,175
    Rides
    0
    Might also be worth looking at the coolant temp sensor, if they misbehave the engine can run richer than it's supposed to. Won't hurt to replace it if it's the 20+ year old original.

  13. #13
    Member sx rider's Avatar
    Join Date
    Apr 2008
    Location
    West Sussex
    Posts
    2,970
    Rides
    0
    Ok cool I look into that then, thanks

    Edit - is the the same as an ETS = Engine Temp Sensor ?
    Last edited by sx rider; 19-05-2020 at 10:13.

  14. #14
    Member sx rider's Avatar
    Join Date
    Apr 2008
    Location
    West Sussex
    Posts
    2,970
    Rides
    0
    According to the RAC website this car falls under Euro 2 emissions standards (petrol)

    CO: 2.2g/km
    HC + NOx: 0.5g/km

    The printouts above don’t correlate to these numbers though, unless I’m being dumb?

  15. #15
    Member sx rider's Avatar
    Join Date
    Apr 2008
    Location
    West Sussex
    Posts
    2,970
    Rides
    0
    I’ve check the manuals and want to just confirm that the coolant temperature sensor is the same thing as the engine temperature sensor?

    Edit - I’m a bit confused by photos on websites of the sensor and not sure if this did right or not? https://m.autodoc.co.uk/hella/937895...k/hella/937895
    Last edited by sx rider; 26-05-2020 at 10:15.

  16. #16
    Member alanjuggler's Avatar
    Join Date
    Feb 2004
    Location
    manchester
    Posts
    9,970
    Rides
    0
    I'd agree with the CAT not seeming to be performing properly - I had something similar.

    I had a magnaflow cat on the RB 180 (180 has similar limits to the S14 as it's past 95, so can't get away with the S13 non-emissions test) - passed the first year test but had problems the second year. turns out the entire cat core had shifted in the bloody pipe, wasn't impressed with magnaflow stuff and wouldn't buy it again.

    if the engine were running rich due to a bad engine temp sensor (and yeah, it is the coolant) then it'd run like it's cold all the time - your HC number suggests it isn't.
    white '94 s13 200sx scrapped - mapped to 1.45bar. OS giken box, garrett GT2876R, 950cc injectors, ORC twin plate, nistune. 349bhp/325lbft @ 1.3bar CA18DET
    white '96 s13 180sx - type g with more kouki bits - RB25DET, GTR steel twin turbo conversion, RB26 crank & rods. 2.6L VVT twin turbo, SR20 OSG box, OSG STR twin plate clutch, Z32 ECU w/ nistune.

    current status: 180 a bit broken but to be repaired.

  17. #17
    Member sx rider's Avatar
    Join Date
    Apr 2008
    Location
    West Sussex
    Posts
    2,970
    Rides
    0
    Ok cool. Thanks for letting me know about the sensor, don’t think I’ll bother changing it based on what you’ve interpreted from the print out. The cat is brand new so next time I’ll make sure it’s really hot and see how it goes!

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •