1989 328 GTS running rough at all speeds | FerrariChat
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1989 328 GTS running rough at all speeds

Discussion in '308/328' started by jim nicholas, May 4, 2023.

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  1. jim nicholas

    jim nicholas Rookie

    May 1, 2023
    8
    Gloucester, MA
    Full Name:
    james nicholas
    #1 jim nicholas, May 4, 2023
    Our 328 GTS started running last fall when i parked it ..... last week i figured it was time to see what was going on with it ..... drained the fuel tank and added fresh gas .......pulled the plugs and they were pretty fowled up so i decided to change them ... check spark and all looked good...... pulled the air cleaner filter out and noticed when rotating the throttle the air intake remained closed / opened very slightly.... and back firing ...... so when i manually open the air breather some, it runs better .... same as when i open the throttle more and open the breather together that the motor runs fine ...... so it seems the signal is not getting to open the air intake breather ...... i read about the frequency valve mine does not seem to be working ..... also the overprotection relay when i tested it on the bench that wire 87 does not send 12 vdc out ..... could all my issues be coming from the over portection relay? Appreicate the assistance....
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  2. Steve Magnusson

    Steve Magnusson Two Time F1 World Champ
    Lifetime Rossa

    Jan 11, 2001
    26,840
    30°30'40" N 97°35'41" W (Texas)
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    Steve Magnusson
    #2 Steve Magnusson, May 4, 2023
    Yes, you need to get the Protection Relay system working (as when it isn't = frequency valve always closed = increases control pressure = makes system very lean). Terminal 87 of the Protection Relay must be +12V whenever the engine (i.e., fuel pump) is running
     
  3. jim nicholas

    jim nicholas Rookie

    May 1, 2023
    8
    Gloucester, MA
    Full Name:
    james nicholas
    #3 jim nicholas, May 4, 2023
    thanks for the response ..... i will get a new relay installed......
     
  4. Steve Magnusson

    Steve Magnusson Two Time F1 World Champ
    Lifetime Rossa

    Jan 11, 2001
    26,840
    30°30'40" N 97°35'41" W (Texas)
    Full Name:
    Steve Magnusson
    #4 Steve Magnusson, May 4, 2023
    Last edited: May 4, 2023
    I would make some measurements and observations before condemning the Protection Relay itself:

    1. First, check to see if the 10A fuse on the Protection Relay is blown. If it is blown, it's usually a sign that the Alternator voltage output has gone crazy, and the Protection Relay did what it was supposed to do, and (intentionally) blew the 10A fuse to protect the injection ECU from an alternator overvoltage. If the (replacement) 10A fuse keeps blowing, you probably need to measure/sort out the Alternator problem (but could still be an internal problem inside the Protection Relay).

    2. Measure the voltage between the large (might be, P, beige) wire on terminal 30 of the Protection Relay and the wires (might be, N, black) on terminal 31 of the Protection Relay = should always be +12V (even key "off").

    3. Measure the voltage between the small wire (might be, P, beige) on terminal 15 of the Protection Relay and the wires (might be, N, black) on terminal 31 of the Protection Relay when the engine is running (even if badly) or with just the fuel pump running (i.e., unplug the safety switch and turn the key "on" = you should hear the fuel pump run) = should be +12V.

    If #1, #2, and #3 all seem OK, but the voltage between the large wire (might be, PN, beige-black) on terminal 87 of the Protection Relay and the wires (might be, N, black) on terminal 31 of the Protection Relay is not +12V when the engine or fuel pump is running = that justifies buying a new Protection Relay.

    If something is not right with #1, #2, or #3 that has to be fixed before condemning the Protection Relay.

    Good Hunting!
     
  5. jim nicholas

    jim nicholas Rookie

    May 1, 2023
    8
    Gloucester, MA
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    james nicholas
    #5 jim nicholas, May 5, 2023
    Thank you. Fuse did test okay, i have 12v volt across it......point 2 - checks with 12 v, point 3 - checks with 12 v. I do not have 12 v coming out of 87.... I hope to get new relay installed soon and hope to be back with a good running car...... thanks for the troubleshooting tips!
     
  6. pappy.72

    pappy.72 Formula Junior

    Nov 13, 2010
    536
    Elgin, IL
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    Dave
    #6 pappy.72, May 5, 2023
    When my protection relay went bad on my 89 it was doing the same thing as yours. I could take the relay out and shake it to cause it to trigger and work again temporarily so I could confirm it was bad. Not sure if that works in all cases when they go bad though. I replaced it and it has been running great ever since.
     
  7. jim nicholas

    jim nicholas Rookie

    May 1, 2023
    8
    Gloucester, MA
    Full Name:
    james nicholas
    #7 jim nicholas, May 5, 2023
    i tried all sorts of tapping, shacking,.... would not change .......
    Thanks for your response ... i feel i am on the right track for replacement..... next will be a new throttle cable .... mine is starting to let go at the throttle body ... half the strands holding ....
     
  8. theunissenguido

    theunissenguido F1 Rookie
    Owner Silver Subscribed

    Jan 21, 2004
    2,678
    Argent/Brasil
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    Guido
    #8 theunissenguido, May 5, 2023

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