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3.2 Can't Hold idle sounds like a cylinder missing

Discussion in 'Mondial' started by moysiuan, Apr 12, 2020.

  1. moysiuan

    moysiuan Formula 3
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  2. Steve Magnusson

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    #102 Steve Magnusson, May 1, 2020
    Last edited: May 1, 2020
    You've got that backwards -- on a KE3-Jet with Lambda system, the two pins in 203 are already disconnected. If you want to operate the system as a KE3-Jet without Lambda, you place a jumper in 203, which connects pin 9 on the KE3-Jet ECU to ground, this "tells" the injection ECU to operate as a without Lambda system. Terminal 31 on 204 is just always ground (203 has nothing to do with the operation of 204). That 203 2-pin socket should physically be somewhere near 204, 205, and 206 (and, if you put a jumper in 203, pin 9 on the KE3-Jet injection ECU will just always measure as ground 0V).
     
  3. moysiuan

    moysiuan Formula 3
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    204, 5 and 6 relays plus the 203 pins are located where? I don't understand which relays these are, the ones in the trunk near the ecu?
     
  4. Steve Magnusson

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    206 is the protection relay with the 10A fuse -- you indicated previously that you know where this is located.
     
  5. yelcab

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    Where do you keep all this knowledge?
     
  6. moysiuan

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    Indeed, I know the location and item, did not know it was referred to as relay 206. Never discovered where the 203 2 pin connector that I would jump is. All I see in the trunk are the ecu, the relays but no 203 2 pin connector (pic of my trunk area attached). Other than the three pin plugged "test port" that has no discernable use (pic 2), what am I missing? There is no 2 pin connector anywhere in there.

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  7. Steve Magnusson

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    #107 Steve Magnusson, May 2, 2020
    Last edited: May 2, 2020
    It could be that Ferrari didn't include 203 in their implementation on your C88 Mondial 3.2 since they only wanted it to always be a KE3-Jet with Lambda system, and 203's presence just got "left behind" in the Bosch-generated documentation as an option that a manufacturer could include. However, since you wrote:

    "Under test 17 on page 70 of the Bosch KE3 manual, the test calls for 5 volts between pins 35 and 9 (and pin 35 and others but my others are blank, so only the 35/9 pins can be checked)."

    This implies there is a wire leaving the KE3-Jet injection ECU connector from the pin 9 position and the only place that wire goes on the schematic is to 203 -- so:

    1. Is there an AR (light blue - red) wire leaving the KE3-Jet injection ECU connector from the pin 9 position?

    2. On your schematic, this AR wire from ECU pin 9 is shown going to position 2 of the large connector serving the 203, 204, 205, and 206 group. Do you have an AR colored wire present in the wires of this connector? If so, you should be able to follow it to 203.
     
  8. Steve Magnusson

    Steve Magnusson F1 World Champ
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    Just serving as more of a translator on this one. I only started looking at this KE3-Jet manual as there was some confusion about each component's function. Bosch does (badly) describe 203 as "Connector for interruption of the lambda probe" which is a description that an English-only speaking Engineer would never write, but it is exactly what someone would get when passing the correct German technical description thru an online translator -- not really technically incorrect, but not the best technical English.
    Also, since the diagnostic tests talk about measuring the voltage on pin 9 vs the voltage on pin 35 (which is a ground) for KE3-Jet with Lambda (and 203 is shown open on this KE3-Jet with Lambda schematic) and, if 203 is closed, pin 9 would also just be ground (so a pin 9 to pin 35 measurement would be meaningless) -- I think it's pretty safe to say 203 would only be jumped closed for without Lambda operation.
     
  9. moysiuan

    moysiuan Formula 3
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    Yes, there is a light blue-red wire in the 9 pin position, and it traces to the fuse protection on the 204 relay. Is the fuse effectively the 203 on my car?

    So if pin 9 goes to the air injection electrovalve, how does a no voltage condition on pin 35/9 indicate a fault in the control unit as per the test 17 descriptor?

    (Also, as an aside the Bosch KE3 manual indicates for adjusting the CO you block the lambda probe by inserting a fuse in a fuse holder near the KE3 control unit. I have no such fuse holder. The build date for my Mondial was Sept. 1987, so was probably among the last batch made, maybe that explains some slight variations in the wiring setup).
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  10. Steve Magnusson

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    #110 Steve Magnusson, May 2, 2020
    Last edited: May 2, 2020
    That assembly with the AR wire is not really part of that relay nor electrically connected to it -- just the plastic is molded with the relay socket plastic.

    What is the yellow "fuse"? Is it actually a fuse, a zero Ohm jumper, or an open jumper just filling the hole?

    "...the Bosch KE3 manual indicates for adjusting the CO you block the lambda probe by inserting a fuse in a fuse holder near the KE3 control unit. I have no such fuse holder." -- that is the fuse holder where you would place either a fuse or a zero Ohm jumper to disable the Lambda system (in order to make the mixture adjustment). If your yellow "fuse" is an intact fuse or zero Ohm jumper = your Lambda system was not working.
     
  11. moysiuan

    moysiuan Formula 3
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    Still looking for the 203 equivalent on my car.

    On your second set of resistance tests on the control unit itself, I am getting about 3,200 ohms on the pin 9 to 35 on the control unit.

    5,200 ohm on pin 2, 8,300 ohms on pin 20 and 4,500 ohms pin 22.
     
  12. moysiuan

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    It is a 20 amp fuse. It is the only blue red stripe AR wire I can trace in the trunk location.
     
  13. Steve Magnusson

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    That "fuseholder" portion is the 203. If that 20 amp fuse is intact = your Lambda system was/is disabled. Have you measured the resistance of that "fuse"?
     
  14. moysiuan

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    Really?? That has not been touched in the 15 years I owned the car. It was previously a one owner car serviced by the Swiss Ferrari dealer, and it had to pass my Province's emmission testing every two years, which it always did with virtually no emissions at idle and 2,500 rpm which the test called for. Hard to believe the car ran so well with the Lambda disconnected? The fuse is a fuse, it has about 3 ohm resistance. This is astounding, but would explain the "missing" 203 connection.

    Since I had the fuse in (jumped equivalent) and the lambda apparently blocked while doing the Jeka described tests, and did not get the 5 volts on the pin 9 to 35, I guess this reconfirms some fault in the control unit. Will re-check after lunch with the lambda connected for greater certainty.

    I am still reeling from the idea I have had the O2 sensor non functional...hard to imagine a dealer leaving the fuse in, but anything is possible.

    Thank you for helping me understand this system.
     
  15. Steve Magnusson

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    No, having that fuse in place ensures that you would only get 0V when measuring between pin 9 and pin 35 (whether the ECU is good or bad) -- please do redo the pin 9 to pin 35 measurement without the fuse in place.

    Doesn't surprise me that you could pass an emissions test without the Lambda system working. A properly adjust mixture and a working cat = very low tailpipe emissions even with no Lambda.
     
  16. moysiuan

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    Still no voltage measured. Zero without the fuse, .1 volt with. The electrovalve relay did click when I reinserted the fuse (I thought this fuse was not connected to the relay?).
     
  17. Steve Magnusson

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    It shouldn't be. If that relay actuates when you insert the fuse = sign that terminal 31 on that relay, that should always be connected to ground, isn't connected to ground. With the fuse removed, measure the resistance between terminal 31 of that relay to the GN (yellow-black) wire in the 3-pin diagnostic connector = should be 0 Ohms. Also, measure the resistance from the GN wire in the 3-pin diagnostic connector to the bare engine block or bare cylinder head or good chassis ground = should also be 0 Ohms.
    If either isn't 0 Ohms = must be investigated/fixed.
     
  18. moysiuan

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    #118 moysiuan, May 2, 2020
    Last edited: May 2, 2020
    I presume you mean the diagnostic tap 186? There is a White with red stripe, a black and a White with blue stripe going to that connector - no yellow black. I am getting 1.4 ohms to the black wire, the middle one on the connector, to relay terminal 31. (ignition in off position). No ohms from the other two wires in the connector to the relay 31.

    0.5 ohms from the black wire of the diagnostic connector to chassis ground.

    Failed relay? Not sure how to explain the black diagnostic wire connector showing some resistance where zero is expected. Unless the black is not the same as the yellow/black you refer to, I can see no yellow black in any of the wiring/connectors.
     
  19. Jeka

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  20. moysiuan

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    So my car has had lambda blocked for 15 years! No matter what other cause I can find, resolving this going forward regardless would be a useful thing.

    Is it possible my car has run so rich over the years I have clogged up a cat converter, and that is causing backpressure that might look like an overfueling condition? The fabspeed cat was new about 10,000km ago. The cause to confirm remains the control unit itself and the lack of the 5 volts, but this lambda fiasco now has me thinking of other causes as well that might relate to the car not running optimal mixture for extended time.
     
  21. moysiuan

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    (all measured with the control unit connector on, and ignition off)
     
  22. Jeka

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    When performing the step 17 measurements with the fuse removed and the ignition key in the "drive" position there is still no 5V at pin 2, 9, 20 and 22?
    Relay 204 is controlled by pin 10 (not 9), it should not click when removing the 203 fuse. My mistake yesterday was that I thought there was a direct connection between 203 and 204. But there isn't, it's only a simple way to provide earth to 203.
     
  23. Jeka

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    Do you have a high idle at cold start? The idle is controlled by the control unit. If so then the control unit is at least oke for that part.
     
  24. Steve Magnusson

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    In the KE3-Jet schematic and the Mondial 3.2 C88 wiring diagram, the center wire of 186 is labeled as GN, but yours being N is A-OK. Here are my comments:

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  25. moysiuan

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    Yes, the car would stumble when started, but would then rise to the high idle, and taper off as he car warmed.
     

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