Air(smog) pump relay clicking | FerrariChat

Air(smog) pump relay clicking

Discussion in '348/355' started by F129b, Dec 5, 2020.

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  1. F129b

    F129b Formula Junior

    Feb 6, 2004
    523
    oc, calif.
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    Robert
    Ive been hearing it clicking and gen spazzing out...the air pump seems to be running nearly all the time. Pulled the relay from the main panel and replaced it with one of same spec. Still clicks (probably a bit less)and pump runs more or less nonstop still.
    What to do/try next? .
     
  2. Qavion

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    Sounds like the relay coil is getting an unwanted earth from somewhere. Is the pump running with just the ignition in RUN (engine off)?
     
  3. Qavion

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    #3 Qavion, Dec 5, 2020
    Last edited: Dec 5, 2020
    If the pump is running with the engine off, try disconnecting the 14 pin plug near the Motronics ECU (behind the leather panel behind the passenger seat on LHD cars).
     
  4. Qavion

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  5. F129b

    F129b Formula Junior

    Feb 6, 2004
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    Pump does not run(and no relay clicking) with key on only.

    So, I should disconnect said 14 pin with car running just to see what happens and then report back?

    Thank you for helping!
     
  6. Qavion

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    oh, that's a bad sign. Your Motronics ECU may be faulty. The ECU turns on the pump (and opens the air valve) by generating a earth for the relay coil. Does the pump run if you turn on the ignition and disable the immobiliser?

    I don't think the car would run if you disconnected that plug. Too many important wires running to the ECU through that plug.
     
  7. Qavion

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    If the pump does stop running after the car has warmed up, but the relay still chatters, there could be a problem with the relay base. Sometimes the relay contacts get dirty or the relay sockets lose their grip.

    Have you tried cleaning the relay socket? The problem seemed to improve when you inserted the new relay. Try inserting it a few more dozen times :D Or use DeOxit or similar product.
     
  8. Qavion

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    Have you confirmed that you have the right type of relay fitted to this position?

    i.e. BOSCH "0 332 015 013"? Not "0 332 015 103"?
     
  9. F129b

    F129b Formula Junior

    Feb 6, 2004
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    Yes I did confirm relay is correct.

    DeOxit DN5 appears to be the one. Any particular tips on application?


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  10. Qavion

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    can't say I've found anything particularly useful for getting into the sockets. I guess dabbing the relay blades in deoxit and inserting and removing it a few times. Clean and repeat.

    I wish there was something like a chamois stick, but much thinner (They were lint free and used for cleaning video tape heads).

    If you're waiting for parts to arrive, what you could do is disconnect that white plug near the ECU and insert a wire into socket 14 (yellow-blue wire)... i.e. not in the plug half shown in the photo... and short the wire to earth. If the relay activates, but doesn't chatter (with the ignition on), you know it's not a relay or relay socket problem, but an ECU problem. Pick your earth point carefully. Sometimes metal bits on the car aren't always good earths.
     
  11. Qavion

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  12. F129b

    F129b Formula Junior

    Feb 6, 2004
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    I’m going to throw $25 at this problem with a new relay and using the deoxit. Will report back when stuff arrives.
    Thank you again


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  13. F129b

    F129b Formula Junior

    Feb 6, 2004
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    Update:
    I have tried deoxit, a new relay and inserting & removing the new relay repeatedly while applying deoxit.
    The relay still clicking on and off absent for a minute or two then it spontaneously starts clacking away.

    What to check/do other than pull the relay..disabling air pump?

    Perhaps a sensor plug or Ecu that governs the air pump needs deoxit


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  14. Qavion

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    #14 Qavion, Dec 19, 2020
    Last edited: Dec 19, 2020
    Activate the pump by earthing pin 14 on plug 41052 as previously instructed (ignition on). Wait a few minutes. Don't flatten your battery. Speaking of which, are you trickle charging the battery to keep it topped up?

    Apply deoxit to that plug and check for pin damage/pushback.

    Do you have an OBD2 reader?
     
  15. Qavion

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    It's unlike a sensor will fail/not fail at the speed of your clicking noise. An OBD2 reader will tell you what the sensor is doing. Otherwise, you will have to do resistance checks on the sensor wiring.

    By earthing that pin, you are breaking up the circuit in half. Then we can focus on the broken half and break that up into sections.
     
  16. Qavion

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    unlikely*
     
  17. F129b

    F129b Formula Junior

    Feb 6, 2004
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    Thank you, No OB2 reader
    I will ground the plug next w ignition off but key ac on.
    Would a good ground be the exposed metal of the vehicle chassis around where the motronic is housed? Or the door pin latch?


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  18. F129b

    F129b Formula Junior

    Feb 6, 2004
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    Yes I do use a trickle charger regularly


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  19. Qavion

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    #19 Qavion, Dec 19, 2020
    Last edited: Dec 19, 2020
    I recall the door pin latch gives a better earth. I think I've had problems with the ECU mount.

    Not sure what you mean, but the key needs to be in the normal "on" position (not accessory). The engine doesn't need to be on for this test. By using this shorting wire, the ECU is taken out of the circuit (so it doesn't matter if the immobiliser is off or on).
     
  20. Qavion

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    I guess that delay of one or two minutes is a clue. Something seems to be heating up and causing the problem.

    I can't see how a pump would cause a clicking relay, but you could always take it out of the equation by disconnecting the pump plug. If the relay still chatters, then it can't be the pump.
     
  21. m.stojanovic

    m.stojanovic F1 Rookie
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    I agree that this seems to be the cause of the problem. If, when the relay is clicking, it does it in fairly regular intervals, it suggest that the issue is in the ECU, i.e. in the relay switching circuitry. It seems that the switching circuit, due to some internal fault, overheats and starts cutting-out. The regular on-off pattern also suggests that this is done by the overheat protection circuit associated with the relay switching component - a switching transistor being part of certain IC inside the ECU. A bad connection in the relay's coil (85, 86) circuit would not cause regular on-offs but cutting out at random.

    With regard to your relay symbol/diagram (top right corner) shown in your post #11, 87B and 87 should not be shown as directly connected. The symbol should be as on this picture:
    Image Unavailable, Please Login

    Robert, what is the Bosch number and the diagram of the relay you are using? Does it have pins 87 and 87b?
     
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  22. Qavion

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    Thanks, Miro. I was trying to find a picture of it. That was the closest. I guess the function is the same (in this particular circuit) ... until something breaks internally.


    Unfortunately, the car only has one ECU, so you can't swap them over as part of faultfinding. At least the earth wire will prove that the problem on the ECU side.
     
  23. m.stojanovic

    m.stojanovic F1 Rookie
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    The important difference between 87b, 87 and 87,87 is that, when the relay is off, 87,87 stay connected to each other and 87b and 87 are separate. There is a reason for the use of 87b, 87 relays as, if the lines going out from these two pins are not separated when "off", there could be some unwanted current or ground path (some back-flow) through whatever is connected to them causing problem. I have not studied your full diagram related to smog pump but, in the case of wrong relay used (like 87, 87), certain back-flow could cause the relay, after being switched off, to be self-energised again, switched off, self-energised again and so on.

    Robert confirmed that he is using a "correct" relay but I have asked for actual details of it, just in case.
     
  24. m.stojanovic

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  25. Qavion

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    I suppose if you wanted to check the wiring all the way to the ECU, you could connect ECU connector contact "57" to earth to activate the relay.

    Image Unavailable, Please Login
    You may need to remove the ECU from its mounts to remove the connector (sometimes removing the connector damages the foam backing on the firewall if you don't do this).
    You will need a fine piece of wire to insert into the connector socket to get a good contact.
     

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