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help.. half my 348 motor shuts down

Discussion in '348/355' started by tommygunct, Feb 25, 2020.

  1. tommygunct

    tommygunct Karting

    Dec 26, 2012
    156
    Ct
    Car starts up and runs fine for about 5 minutes then sputters a little and the whole side Bank goes out I have switched MAF sensors from one side to the other same thing I have changed fuel filters spark plugs check Spark installed two new O2 sensors and took apart and clean my throttle bodies but it still keeps happening just on one half of the motor on the half that goes out if I take the MAF plug off the motor stays the same if I go to the other side and take the MAF plug off it dies right out anybody have any suggestions any help would be appreciated
     
  2. MAD828

    MAD828 Formula 3
    Silver Subscribed

    Oct 8, 2011
    1,506
    Sydney
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    Elliott Caras
    Crank sensor?
     
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  3. Wingnut

    Wingnut Karting

    Feb 11, 2005
    70
    Corolla, NC
    See my post on the Mondial forum "Left bank running rich". The Mondial T has the same engine as the 348 I am told.
     
  4. Wade

    Wade Two Time F1 World Champ
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    Mar 31, 2006
    28,756
    East Central, FL
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    Wade O.
  5. Pangea

    Pangea Formula Junior

    Mar 27, 2011
    389
    UK
    Full Name:
    Nick
    Can you identify which bank? Any slow down lights or CELs on the dash? Can you pull any codes? ( maybe no bulbs fitted) If not my first thing would be to disconnect the cat ecus and thermocouples just to take them out of the equation before digging deeper. Few seconds work. Many years ago I had a very similar situation at start up from cold. About 5 mins or so in it dropped a bank. It was a cat ecu. Didn't even get up to full temp. I run decat pipes so I left it disconnected.
     
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  6. tommygunct

    tommygunct Karting

    Dec 26, 2012
    156
    Ct
    the cat and thermos are already disconected have been for a long time
    no lights on the dash i have an 89 so no code lights to pull codes from it has the old motec with 1 throttle position switch
     
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  7. tommygunct

    tommygunct Karting

    Dec 26, 2012
    156
    Ct
    Do you think it might be a crank sensor have you ever changed one in your car are they a pain in the ass what is usually the problems that go on when a crank sensor goes bad
     
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  8. Wade

    Wade Two Time F1 World Champ
    Rossa Subscribed Owner

    Mar 31, 2006
    28,756
    East Central, FL
    Full Name:
    Wade O.
    I had a bit of trouble following your dilemma as described (run-on sentence without punctuation). So I broke it down... did I get it right?

    Car starts up and runs fine for about 5 minutes then sputters a little and the whole side (i.e. one Bank) goes out.

    I have switched MAF sensors from one side to the other and the same thing happens.

    I have changed fuel filters, spark plugs, checked the spark, installed two new O2 sensors and took apart and cleaned the throttle bodies, but it still keeps happening (just on one half of the motor)

    On the half that goes out, if I take the MAF plug off, the motor stays the same.

    If I go to the other side and take the MAF plug off, it dies right out.

    Anybody have any suggestions? Any help would be appreciated.​
     
  9. MAD828

    MAD828 Formula 3
    Silver Subscribed

    Oct 8, 2011
    1,506
    Sydney
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    Elliott Caras
    My car was recently dropping a bank when driven hard. It was the 5-8 side and was the crank sensor for that bank. It was not that bad to change and the 5-8 side is the difficult one.
     
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  10. tommygunct

    tommygunct Karting

    Dec 26, 2012
    156
    Ct
    that's the one I think is bad on mine why was it so hard to change is it that stupid plug that's all the way underneath the car near the alternator
     
  11. MAD828

    MAD828 Formula 3
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    Oct 8, 2011
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    Elliott Caras
    I went from underneath with a small Allen key once the bolt is broken loose it’s easy to change. I didn’t have a lot of leverage to loosen it but it is doable.
     
  12. steved033

    steved033 F1 Rookie
    Silver Subscribed Owner

    Apr 12, 2017
    2,514
    Atlanta, GA
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    Steve D.
    bad ground? dirty connector somewhere?

    sjd
     
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  13. Iltorored

    Iltorored Rookie

    May 17, 2013
    3
    Houston
    Full Name:
    John Murphy
    I had the same issue awhile back and what worked for me was unplugging the tps on the bank that drops and sprayed contact cleaner on both the plug and the socket. Disconnect the battery first.


    Sent from my iPhone using FerrariChat.com mobile app
     
  14. Ferrarium

    Ferrarium Formula 3
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    Jul 28, 2018
    1,806
    Central NJ
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    Eric
    You can get the crank sensor very easily andnin a fraxtionmof the time from the passenger wheel well if you remove the liner with a 1/4" 2 foot extension and a swivel.

    Sent using FerrariChat.com mobile app
     
  15. A348W

    A348W Formula 3

    Jun 28, 2017
    1,099
    North Wiltshire, UK
    If your Cat ECUs are disconnected and from what you have said:
    - its not your MAFs;
    - its not plugs/leads/o2 sensors.....

    next just replace the crank sensors (cheap from Kia; see master sticky).

    If that doesn't cure it you need to start swapping parts etc;
    - clean all electrical connections with cleaner
    - swap relays for ECUs;
    - swap relays for fuel pumps;
    - put a volt meter on your fuel pumps to see if one of those is being temperamental;
    - swap your ECUs over ;
    - check earths.

    If none of that finds an issue, then replace the following (not overly expensive)
    - power modules and coils;

    If none of that works, come back for more help; and hopefully somebody with some deep understanding will step in!!!

    Good luck. I've had similar issues and feel your pain/hassle. For me 1 incident was Cat ECUs, and another was crank case sensors.
     
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  16. johnk...

    johnk... F1 Veteran
    Owner

    Jun 11, 2004
    7,742
    New England/FL
    Check fuel pressure and check to see if injectors are firing.
     
  17. Jeff Pintler

    Jeff Pintler Formula Junior
    Silver Subscribed

    Jul 20, 2005
    518
    Richland
    Full Name:
    Jeff Pintler
    Another place to check are the 6mm screws near the driver cam cover, I can't remember if they were on the top or the bottom but the grounds
    for the motronic 2.5 are tied there. And of course, do you have any way to verify fuel pressure on the dead side?

    Jeff Pintler
    89 348tb, 86tr, 99 360 3pedal, 05 S-160 Bobcat
     
  18. Ferrarium

    Ferrarium Formula 3
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    Jul 28, 2018
    1,806
    Central NJ
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    Eric
    I'd switch maf, coil and ignition module from one back to other and see if problem changes banks. No cost and takes 20 min.

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