Correct exhaust gas #s on an 83 308QV | FerrariChat

Correct exhaust gas #s on an 83 308QV

Discussion in '308/328' started by dwhite, May 2, 2019.

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  1. dwhite

    dwhite F1 Rookie

    May 30, 2003
    3,499
    Bklyn, NY/Vero Beach
    #1 dwhite, May 2, 2019
    Have rebuilt my entire injection system due to a poor/erratic running condition and of course I now need to dial it in perfectly. The car ran beautifully for all 18 years of my ownership and I would like to get back to perfect.

    What was done: injectors cleaned replaced rubber seals, WUR rebuilt and calibrated, FD rebuilt and callibrated, new fuel filter.

    The car runs but the A/F adjustment is not correct it's been touched and it's close. Have read the probst book and have looked at the mondial QV section of workshop manual, but really looking for 1983 308 QV US spec car.

    Last piece of the equation the air pump was removed by the original owner back in '83. If it would make a difference in set up #s.

    Have a person willing to coming by my storage place with a 5 gas analyzer to get it dialed in. Any numbers would be helpful. Thank you.
     
  2. Steve Magnusson

    Steve Magnusson Two Time F1 World Champ
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    Jan 11, 2001
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    Steve Magnusson
    #2 Steve Magnusson, May 2, 2019
    See page 15 in your 260/83 US 308B/S OM:

    "With warm engine, probing from the eight CO analysis pipes connected together" (meaning with no air injection and upstream of the cats)
    CO = 1% +/- 0.2%
    HC max = 100 ppm

    But those are very tight limits, and I wouldn't slit my wrists if the adjustment was something like CO = 1.5% and HC = 150 ppm - JMO.

    You indicate that the air pump is already gone, so, if you don't have cats, you could make the exhaust gas measurement at the tailpipes. If you do have cats, you'll have to sample somewhere upstream from them.
     
  3. thorn

    thorn F1 Rookie
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    Aug 7, 2012
    3,322
    Tallahassee, FL
    #3 thorn, May 2, 2019
    I adjusted the A/F on my 85 QV Euro (no cats, no emissions equipment) last week. Here are the numbers I currently have:

    CO: 2.5%
    HC: 466p
    CO2: 12.1%
    O2: 2%
    NOx: 34p
    AFR: 14.7

    Values were taken on a warmed-up engine, at 1100 rpm idle, directly from the tailpipe. I'd like for CO to be a bit lower by at least another -1%, but for now I'm leaving it as-is. I believe CO and HC might drop if i got leaner (the higher-than-spec HC is bothering me), but 14.7 is already a bit more lean than I'd like.
     
  4. dwhite

    dwhite F1 Rookie

    May 30, 2003
    3,499
    Bklyn, NY/Vero Beach
    #4 dwhite, May 3, 2019
    Thanks Steve and Thorn. I'll look at my OM and see what is says, Ferrari does give more info than any american owners manual I have ever seen and I always forget, but I forget a bunch anyway ;-).

    Hopefully it will be resolved this weekend and I will post an update.Trying to get it done before I leave next week for 3 weeks in FL.
     
  5. miketuason

    miketuason F1 World Champ
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    Feb 24, 2006
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    #5 miketuason, May 3, 2019
    Are you driving your car to FL?
     
  6. Rifledriver

    Rifledriver Three Time F1 World Champ

    Apr 29, 2004
    34,103
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    #6 Rifledriver, May 3, 2019
    HC is high and CO2 is low suggesting poor combustion efficiency. O2 doesn't really make me think being rich is the problem.
     
  7. Rifledriver

    Rifledriver Three Time F1 World Champ

    Apr 29, 2004
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    #7 Rifledriver, May 3, 2019
    Can easily be done with a dwell meter on the frequency valve. Pick a range on the dwell meter and set the frequency valve at 50% of the scale. You do not have the diagnostic capabilities of a 4 gas analyzer but it is in the estimation of many to be the best way to set mixture.
     
  8. thorn

    thorn F1 Rookie
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    Aug 7, 2012
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    #8 thorn, May 3, 2019
    That's the feeling I'm having as well; i'd hope to get HC in the 250-ish range and CO2 closer to 15%. As I was initially dialing it in, a leaner 12.2 mix wasn't that great either... gas values were mostly all worse. So it's better than it was, but still not where I wish it was.

    Plugs are new & properly gapped, timing ignition advance/numbers are right at about factory spec, good injectors, solid vacuum with no leaks, and a steady idle. I haven't done a compression or leakdown test yet, but starting to feel like those are my only next-best options to figure out what's up.

    Off to the garage now with Fluke in hand... going to check the spark cables and make sure the resistance values are happy.
     
  9. dwhite

    dwhite F1 Rookie

    May 30, 2003
    3,499
    Bklyn, NY/Vero Beach
    #9 dwhite, May 3, 2019
    My 83 does not have lambda on it so no dwell meter capabilities, but that sounded easy.

    Reminded me of checking the points in my old TVRs ignition.
     
  10. dwhite

    dwhite F1 Rookie

    May 30, 2003
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    Bklyn, NY/Vero Beach
    #10 dwhite, May 3, 2019
    No, flying down. It would be a nice drive if I were to stay off I95.
     
    miketuason likes this.
  11. miketuason

    miketuason F1 World Champ
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    #11 miketuason, May 3, 2019
    Oh yes, that would be a nice drive. I love long driving in my QV.
     

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