Another "Check Eng 5-8" and "Slow Down 5-8" Thread | FerrariChat
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Another "Check Eng 5-8" and "Slow Down 5-8" Thread

Discussion in '348/355' started by DavidLMcAfee, Dec 14, 2015.

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  1. DavidLMcAfee

    DavidLMcAfee Formula Junior

    Nov 22, 2015
    355
    East TN
    Full Name:
    David McAfee
    #1 DavidLMcAfee, Dec 14, 2015
    Last edited: Dec 14, 2015
    I know there are a ton of these in FChat, and I searched them, but I didn't find what I needed, so here is another.

    I bought my 348 Saturday based on the PPI and the service records that came with it. When I drove it away from the shop that did the PPI (Foreign Cars Italia in Greensboro, NC), everything was fine and dandy.

    Yesterday I drove the car home to Knoxville. It was a 4 1/2 hour drive, and I never got above 80. I spent most of the drive at 70mph in 5th gear running just a tick over 3K rpm.

    After about 20 minutes of no issues, the Check Eng 5-8 light came on. The car was still running fine, though. A few minutes later it went off. Then it came on again, then off again, etc. All the while the car was running fine. Then it lost power. I'm assuming the 5-8 bank shut down. (Though I didn't know that the time.) A minute or so later the Slow Down 5-8 light came on. I slowed the car down to 60 and watched the light, ready to pull over if needed. The light went off, then came back on, then went off again. About two minutes after it went off, the engine began running normally again. From start to finish, the issue lasted about five minutes. The Check Eng 5-8 light continued to come on intermittently, but I didn't have any further issues with power or the Slow Down light.

    Then I stopped for lunch. Again, about 20 minutes after I got back in the car and down the highway, the car repeated the whole cycle. Again, once power returned, the car ran fine with intermittent Check Eng 5-8 light activity.

    Stopped for gas an hour later and sure enough, about 20 minutes after I got going, the whole thing happened again.

    Got the car home without further incident. A little later I took it to the store for milk (any excuse to get back in the car) and the Check Eng 5-8 light stayed on the entire time. No Slow Down lights or loss of power, though. When I got home I opened up the rear decklid and looked at the cats, they weren't glowing or anything, but I don't have the means at the moment to check their temp, so I don't know how hot they were.

    So, any ideas on what the issue might be? ECU? Thermocouple? Something else? I've been filtering through the current crop of Check Eng 5-8 and Slow Down 5-8 threads, but most of them seem to be about one or the other, not both.

    Thanks for any help. I'd like to try and tackle this myself, if possible. But I'm not above calling my local shop if need be.
     
  2. bayferrari

    bayferrari Karting
    Silver Subscribed

    Mar 10, 2011
    95
    Bay Area
    Full Name:
    William
    #2 bayferrari, Dec 14, 2015
    I'm having similar symptoms with my 91 348. I get the slow down light 1-4. I've swapped exhaust ECU's, replaced both catalytic converter sensors, and thermal couple for the 1-4 bank. Also replaced cam timing sensor. Mine will also run fine till I get the 1-4 sdl and then the bank shuts off. I pull over to the side of the road, shut the car off and restart, problem goes away but still get the sdl 1-4, usually goes out after a few minutes. The codes I am getting are the exhaust overtemp, I think they are 4121, 412?. Car had a major 6 or so months ago. I'm starting to think cats are bad. Another interesting thing is I will get the sdl before I even start the car and a couple of times the bank wont even fire on cold start up. Once again, turning the car off and restarting will make it go away. Don't want to hijack the thread but it's getting frustrating.
     
  3. ClydeM

    ClydeM F1 World Champ
    Owner Rossa Subscribed

    Nov 4, 2003
    11,763
    Wayne, NJ
    Full Name:
    Clyde E. McMurdy
    #3 ClydeM, Dec 14, 2015
    My348.com for pulling the codes from the ecu
     
  4. RaginBull

    RaginBull Formula Junior

    Oct 24, 2006
    996
    Bay Area, CA
    Full Name:
    Darryl
    #4 RaginBull, Dec 14, 2015
    First off, DONT PANIC!! Im sure you are probably going through buyers remorse LOL but welcome to the world of 348 ownership.

    1. These cars need to BREATH!! Give it an old Italian Tune Up. What that means is take it out on the freeway and rev the living crap out of it. Our cars behave better when they are driven hard. If you continue to get the check engine lights, proceed to number 2

    2. Follow the steps to check the Engine Codes on My348.com. The access panel is right behind the driver seat. Once you get the codes, disconnect the battery for 10 minutes reconnect. Make sure all electronics are turned off (no ac/heater, lights, etc.) Start the car and and go through the ECU relearn. You will notice an immediate improvement, and the codes will clear. If you truly had a problem then the lights will come back

    3. Post the codes you obtained in this thread. By the way, next time you feel power loss, shut the car off while you are driving then back on to regain power. Again, drive it HARD!!
     
  5. RaginBull

    RaginBull Formula Junior

    Oct 24, 2006
    996
    Bay Area, CA
    Full Name:
    Darryl
    #5 RaginBull, Dec 14, 2015
  6. DavidLMcAfee

    DavidLMcAfee Formula Junior

    Nov 22, 2015
    355
    East TN
    Full Name:
    David McAfee
    #6 DavidLMcAfee, Dec 14, 2015
    Last edited by a moderator: Sep 7, 2017
    Okay, I pulled and cleared the codes. They were:

    1211
    1212
    1114
    4122

    4122 was the overheated Cat.
    1114 was the O2 sensor (that was replaced recently.)
    1211 and 1212 both had to do with O2. I called my local place and the guy told me to switch my MAFS from one side to the other to see if that was the issue. When I went to do that, I noticed that these hose clamps (see pic) were so loose that I could turn them all the way around with my finger. Wondering if that could be part of the problem.
    Image Unavailable, Please Login
     
  7. RaginBull

    RaginBull Formula Junior

    Oct 24, 2006
    996
    Bay Area, CA
    Full Name:
    Darryl
    #7 RaginBull, Dec 14, 2015
    That an most commonly, dirty MAF leads. Buy some MAF cleaner and make sure the leads are squeaky clean
     
  8. DavidLMcAfee

    DavidLMcAfee Formula Junior

    Nov 22, 2015
    355
    East TN
    Full Name:
    David McAfee
    #8 DavidLMcAfee, Dec 14, 2015
    And now for my "I'm a big dummy" moment.

    I tightened the hose clamps and then started the car just to see how it would do. (I can't take it for a drive yet because I'm home alone with the baby.) Imaginey shock when BOTH check engine lights stayed on! 1-4 and 5-8. I was sitting there wondering how a tighter hose clamp could screw things up. I shut the car off and walked around to look.

    Then I slapped my forehead so hard I almost drew blood. I forgot to reconnect the MAF cables. I'd disconnected them in anticipation of swapping them over.

    I will contact my Alma Mater later and ask for a refund.
     
  9. DavidLMcAfee

    DavidLMcAfee Formula Junior

    Nov 22, 2015
    355
    East TN
    Full Name:
    David McAfee
    #9 DavidLMcAfee, Dec 14, 2015
    Is there anything specific I should use to clean them?
     
  10. RaginBull

    RaginBull Formula Junior

    Oct 24, 2006
    996
    Bay Area, CA
    Full Name:
    Darryl
    #10 RaginBull, Dec 14, 2015
  11. DavidLMcAfee

    DavidLMcAfee Formula Junior

    Nov 22, 2015
    355
    East TN
    Full Name:
    David McAfee
    #11 DavidLMcAfee, Dec 14, 2015
    UPDATE: I took her out for a 40 minute drive this evening. Hit the interstate and ran at 70-80mph the whole time. No check eng lights. Car ran like a top. :)
     
  12. RaginBull

    RaginBull Formula Junior

    Oct 24, 2006
    996
    Bay Area, CA
    Full Name:
    Darryl
    #12 RaginBull, Dec 14, 2015
    Nothing like giving her an ole Italian Tune Up! :)
     
  13. John Glen

    John Glen Formula Junior

    Dec 30, 2009
    494
    Victoria, B.C, Can.
    Full Name:
    John Glen Wesanko
    #13 John Glen, Dec 14, 2015
    Cat ecu boxes are famously bad on these cars. This is likely giving bad signal to engine ecu causing the "check engine light" and soon to follow "slow down light" which will shut down that cyl bank ie 5-8. My car when purchased had the cat ecu's disconnected and ran fine. As soon as I re-connected the boxes I had the exact same symptons. ps, these units are about $ 400 each.
     
  14. bballto

    bballto Karting

    Mar 10, 2014
    155
    #14 bballto, Dec 15, 2015
    John, if your Cat ecu boxes are disconnected how would you know if your Cat's get dangerously hot.
     
  15. yelcab

    yelcab F1 World Champ
    Consultant

    Nov 29, 2001
    13,476
    San Carlos, CA
    Full Name:
    Mitchell Le
    #15 yelcab, Dec 15, 2015
    You don't.
     
  16. bpu699

    bpu699 F1 World Champ
    Owner Silver Subscribed

    Dec 9, 2003
    17,567
    wisconsin/chicago
    Full Name:
    bo
    #16 bpu699, Dec 15, 2015
    Are your cars anything like the testarossa's? I was getting slow down lights... which I figured were errors as they flashed whether the car was hot or cold...

    Took the cats out and put in bypass pipes... That should obviously keep the thermocouples from showing an overtly hot condition...

    No change. The light just randomly pops up at times out of the blue...

    I suspect most of these are glitches... probably ECU related...

    Taking out the cats prevents the thing you are really worried about - a fire...

    Make sure you check for an overtly rich condition, and get an AFR meter ($200) to make sure the car isn't actually running super rich...
     
  17. emac

    emac Formula Junior
    Silver Subscribed

    Sep 14, 2014
    851
    upstate SC
    Full Name:
    ernest
    #17 emac, Dec 15, 2015
    Glad you are getting it sorted. I had some of those same issues on my 355 when I got it. Replaced an ECU and TC, but still got some cat codes popping up. I went through all the intake and exhaust connectors/clamps and the codes went away.

    I even purchased new cats but I haven't installed them. I believe my cat codes were related to intake/exhaust leaks rather than a bad cat.

    Any new relationship requires extra TLC in the beginning.
     

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