348 Failed Smog Results - Diagnosis???? | FerrariChat
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348 Failed Smog Results - Diagnosis????

Discussion in 'Technical Q&A' started by Kevallino, Jul 6, 2004.

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  1. Kevallino

    Kevallino Formula 3

    Feb 10, 2004
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    Kevin
    #1 Kevallino, Jul 6, 2004
    Last edited by a moderator: Sep 7, 2017
    1994 348 Spider, stock exhaust. I have made no changes to the car but I've only just got it a few weeks ago and haven't driven much yet.

    Here's the results - I haven't had the car long so have no prior "running right" comparisons to add input. I can say the exhaust smell is pretty strong which I guess is consistent with the results?

    Any additional information please feel free to ask although I might not have it!!

    Cheers
    Kevin
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  2. mikeg

    mikeg Rookie

    Nov 3, 2003
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    #2 mikeg, Jul 6, 2004
    Are you adding any octane suppliments? what kind of gas are you burning?

    I have a mondi qv and put some higher octane gas in right before testing. The result was a failure. When I burned it off, and retested with 93 oct. it passed.

    Watch out for injector cleaner as well I have been told..

    Mike
     
  3. Steve Magnusson

    Steve Magnusson Two Time F1 World Champ
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    Jan 11, 2001
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    #3 Steve Magnusson, Jul 6, 2004
    Those are tough HC/CO limits that would require very healthy, working cats (and a properly working injection system).

    ~1% CO and a couple of hundred HC PPM are typical values for the upstream (entrance) side of the cat for a good-running, injected, Lambda-controlled engine so the possibilities might be:

    1. a previous owner "cleaned" out the cat(s), or

    2. the cat is still intact, but it's catalytic surfaces are fouled.

    If you do an internal visual inspection of the cat(s) and everything looks OK/intact then you'd need to have a shop measure the CO/HC at the cat entrance side to decide what to do next -- JMOs...
     
  4. Miltonian

    Miltonian F1 Veteran

    Dec 11, 2002
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    Jeff B.
    #4 Miltonian, Jul 6, 2004
    First time I went in for the test with my 348, I only drove it about 5 miles to the station, and it failed. On the advice of the tester, I just hopped in and drove it for about an hour, put on about 50 hard miles, then went back to the station and retested it. It passed by a good margin. The lesson: don't do the test unless the engine is THOROUGHLY warmed up.
     
  5. writerguy

    writerguy F1 Veteran

    Sep 30, 2003
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    Otto
    #5 writerguy, Jul 6, 2004
    It is not the engine that needs to come to heat it is the CAT... But running a hot engine will definitely make the difference
     
  6. Kevallino

    Kevallino Formula 3

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    #6 Kevallino, Jul 6, 2004
    Interesting as the smog place I went to isn't that far from me. However, I have gone ahead and ordered HyperFlow cats anyway as I was looking for an excuse to do so!! Tubi is on its way so I want to do both at once.

    But I will give it a good run prior to the check. Both my water and oil temp were at operating temperature before I got there so I assume the cats would be hot as well but maybe not.

    As for the other comment about grade of gasoline, 91 octane is the best we get in California although there are a couple of places with 100 octane unleaded at the pump (nearly $6 a gallon but I use a bit in my Euro Benz) and I don't believe in additive crap so nuthin' but gasoline in the tank.

    As I said the car "smells exhausty" so perhaps the PO had his/her way with the guts of my CCs.

    Thanks for the help but more is welcome....

    Cheers
    Kevin
     
  7. rexrcr

    rexrcr Formula 3
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    #7 rexrcr, Jul 6, 2004
    Not true. Cold engine will run richer, it has to. Yes, the catalyst does the most work, but it's a system, and the combustion chamber efficiency is an important part. Coming up to normal cylinder operating temperature is key. Granted that modern engines spend a bit less time coming up to temperature, and that characteristic is driven by ever more stringent exhaust emissions standards.

    Agreed, never smog test an engine without a minimum 20 minute drive. Same for storage in winter and one desires to take the car for a spin around the block to warm things up. Six minutes later, it's parked in storage again, much the worse for wear. Better off not driving for four months.


    Best regards,

    Rob Schermerhorn
     
  8. fatbillybob

    fatbillybob Two Time F1 World Champ
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    Aug 10, 2002
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    #8 fatbillybob, Jul 6, 2004
    348's run super clean even wo cats. GEtting everything really hot really only helps a marginal car. Your numbers are off the map for a 348. IMO you have something else wrong and it is likely electrical.
     
  9. ferrarilou

    ferrarilou Formula Junior

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    Lou Menditto
    #9 ferrarilou, Jul 7, 2004
    Did the previous owner perchance modify the engine ECUs? If he/she had swapped in a performance chip, for example, that could cause the issue.


    Lou
     
  10. Kevallino

    Kevallino Formula 3

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    #10 Kevallino, Jul 7, 2004
    I will be pulling the codes shortly so perhaps that will give me some guidance as to where to start. I absolutely don't want to just whack some new cats on it only to ruin them due to some upstream problem.

    Will follow up here when my bloody work schedule gives me a few minutes to go pull the codes.

    Cheers
    Kevin
     
  11. Kevallino

    Kevallino Formula 3

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    #11 Kevallino, Jul 7, 2004
    Bank 1-4

    4114 - TDC control unit recognition
    1111 - Hot wire air flow meter
    1211 - Lambda regulation

    Bank 5-8

    1121 - RPM sensor

    Have one opinion to check grounds on valve covers - anyone else??

    Cheers
    Kevin
     
  12. rexrcr

    rexrcr Formula 3
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    #12 rexrcr, Jul 12, 2004
    Bank 1-4

    4114 - TDC control unit recognition
    Not too likely as a true error, though requires confirmation with oscilloscope.
    1111 - Hot wire air flow meter
    Check pin connectors. Checking this circuit with a VOM should show steady voltage at idle, then increase rpm to 3000 for say 30 seconds, then drop to idle, then turn off the engine and watch for the voltage to jump simultaineously to clean the hot wire of debris.
    1211 - Lambda regulation
    Bingo. Dig into this circuit. Search under this topic for diagnostic procedure. Search old archives too.

    Bank 5-8

    1121 - RPM sensor
    Non-issue. This just means you checked the error codes with the engine off.


    Best regards,

    Rob Schermerhorn
     
  13. Kevallino

    Kevallino Formula 3

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    #13 Kevallino, Jul 12, 2004
    Rob

    Thanks - from my prior research I knew about the 1121 code being a non-issue. Will do searches re: lambda circuits. Also I got my shop manual in the mail last week from Martin at Cavallino so have a place to look for things as well. Will get it sorted I am sure.

    Thanks again.

    Cheers
    Kevin
     

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