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New problem

Discussion in 'Technical Q&A' started by kendogg41, Apr 15, 2017.

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  1. kendogg41

    kendogg41 Rookie

    Mar 21, 2016
    18
    Auburn, GA
    #1 kendogg41, Apr 15, 2017
    Last edited: Apr 15, 2017
    Thanks for all of the previous help. Still having wiring issues with this '95 355 (US car). Everything is where it belongs, but the DME is not firing the drivers side ignition coil. Passengers side, just fine. It appears to be a short somewhere. Have swapped ignition drivers & DME to both sides and no change. With my high impedance test light, it appears to fire once, then the light just dulls, whereas the passengers side flashes everytime the DME signals the coil to fire.

    The wiring diagrams I have for this car are a 1994 service manual, and from consulting it to test the wiring to the crank sensors, I've determined that the diagram and pinouts are simply incorrect. Can anybody help me with pinouts for the 3-pin connector on the drivers side (5-8) ignition coil, and their corresponding pin#'s on the drivers side DME connector so I can start testing the wiring itself? Thanks a bunch!
     
  2. johnk...

    johnk... F1 World Champ
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    Jun 11, 2004
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    John Kreskovsky
    It could be the TDC sensor for the 1-4 bank. The coil pins are Pin 1 and 3 are connected to the ignition control module which controls the firing of each side of the coil. Pin 2 is common to both sides primary coils. Not 100% sure but typically pin 2 would provide the supply voltage, 12 V, from the DME (ECU). Pins 1 and 3 are connections to ground which the ignition module opens and closes based on signal from the DME (ECU), which the DME (ECU) determines from signal it receives from the TDC sensor. All the parts, TDC sensor, coil and ignition module can be had for a total under $200. The 1-4 TDC sensor is a batch to replace since the AC compressor is in the way.
     
  3. kendogg41

    kendogg41 Rookie

    Mar 21, 2016
    18
    Auburn, GA
    We've swapped the TDC sensor with a new one, as well as the cam sensor. As stated, the ECU is ground switching the passengers side bank just fine, whereas it's not the drivers side bank. We've swapped ignition modules left-right,a nd DME's left-right. It's absolutely a wiring issue. I just need the correct pins, since the wiring diagram I have cannot be trusted.


    Wait....The 1-4 TDC sensor is behind the a/c compressor? I thought that was the 5-8? It doesn't matter I guess, 1-4 have good spark.
     
  4. johnk...

    johnk... F1 World Champ
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    #4 johnk..., Apr 15, 2017
    Last edited: Apr 15, 2017
    I guess I miss read your post. I though you said 1-4 was the problem. But yes, 1-4 TDC is blocked by the Ac compressor. 5-8 is on the bottom of the engine.

    According to what I have, pins for coils are as stated for either side. Looks to me that the control for the ignition module connect to pins 1 and 20 of the DME. These should be blue and blue/black wires. Ground for the ignition module should be a brown wire. Wires from the coil to ignition module should be red (coil pin 3) and red/black (coil pin 1). Wire from coil pin 2 to power should be Orange/black or yellow/black (does not connect to DME but to a power block from the ignition switch (key on/off)). The blue and blue/black wires from the ignition module are the only ones connected to the DME.

    Best I can do.
     
  5. spicedriver

    spicedriver F1 Rookie

    Feb 1, 2011
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  6. yelcab

    yelcab F1 World Champ
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    #6 yelcab, Apr 15, 2017
    Last edited by a moderator: Sep 7, 2017
    Here is the pix

    Pin 2 of the IGN coil, org-black goes to ground outside the picture area.
    The blue wire of the POWER MODULE goes to pin 1 of the ECU unit
    The BLUE BLACK wire of the POWER MODULE goes to pin 20 of the ECU unit
    The BROWN wire of the POWER MODULE goes to ground.
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  7. johnk...

    johnk... F1 World Champ
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    #7 johnk..., Apr 15, 2017
    Last edited by a moderator: Sep 7, 2017
    Orange/black is power.
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  8. yelcab

    yelcab F1 World Champ
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    I stand corrected.
     
  9. kendogg41

    kendogg41 Rookie

    Mar 21, 2016
    18
    Auburn, GA
    OK, so it's DME > ignition module > coil. Got it. I'll be testing this wiring today and report back. I suspect I'll find a few pinched or otherwise shorted wires before I'm done. You guys are fantastic, thank you!
     
  10. kendogg41

    kendogg41 Rookie

    Mar 21, 2016
    18
    Auburn, GA
    #10 kendogg41, Apr 17, 2017
    Last edited by a moderator: Sep 7, 2017
    So quick check - the wire colors going to the drivers side (5-8) coil do not match what you guys are saying they should be. Here's what I have.

    Instead of this:

    1 Red
    2 orange-black
    3 red-black

    I have this apparently:
    1 white-green
    2 can't tell
    3 white-blue


    Thoughts?
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  11. yelcab

    yelcab F1 World Champ
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    I know what your problem is. That is the 3 pin connector for the idle valve. The mechanic before swapped the two connectors idle valve for coil and vice versa. It is never going to fire. Swap them back. Good luck.
     
  12. kendogg41

    kendogg41 Rookie

    Mar 21, 2016
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    Auburn, GA
    Holy crap it runs! Thank you guys SO MUCH!!!
     
  13. yelcab

    yelcab F1 World Champ
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    I love happy endings.
     
  14. Patrick Dixon

    Patrick Dixon Formula 3

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    Yes, good skills yelcab.
     
  15. yelcab

    yelcab F1 World Champ
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    It's not skills, I got fed up with the wiring diagrams so I made very large copies of all 348 and 355 schematics with all the wiring colors deciphered and the connector names added right at the connectors. Once he showed me the wire colors, I knew what his problem was.

    It also helps that I have the same car and I recall there are two 3-pin connectors in that area, next to each other.
     
  16. Gerry328

    Gerry328 F1 Rookie
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    This is what makes FChat a great resource.
     
  17. taz355

    taz355 F1 Veteran
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    Nice call Mitchell
     
  18. jjtjr

    jjtjr Formula Junior

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    That is very helpful to have those schematics well detailed. I too think those diagrams in the wsm are prehistoric. And that is unfortunate because the wiring that is actually in the car is detailed well enough from the factory. Great info!
     
  19. yelcab

    yelcab F1 World Champ
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    Each wiring diagram page in the WSM is cut into 4 pieces and sent to the four corners of the globe. I had to resize, enlarge, rotate, combine them into a single sheet, add the english names for each component (idle valve, instead of F11), add wring colors, then take them to Kinko to print out to size 24 x 36 inches.

    Now they are readable,
     
  20. Qavion

    Qavion F1 World Champ
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    +1

    Thanks for posting those pics, guys... I was having problems reading some of the colour codes. They help fill in some of the gaps in the diagram I was redrawing.

    By the way, shouldn't that power wire to coil be Yellow-Black? ("GN"/ Giallo/Nero)?

    Work in progress....

    1994 F355 Ignition System (Cylinders 5~8)

    Thanks,
    Cheers
     
  21. johnk...

    johnk... F1 World Champ
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    Brilliant! Good call, Mitch.
     
  22. johnk...

    johnk... F1 World Champ
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    #22 johnk..., Apr 20, 2017
    Last edited by a moderator: Sep 7, 2017
    By the way, for those struggling to trace wires on the WSM diagrams if you open the WSM with Adobe and click on the page it highlights the background in blue and the wre traces become clearer. See attached.
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  23. kendogg41

    kendogg41 Rookie

    Mar 21, 2016
    18
    Auburn, GA
    #23 kendogg41, Apr 24, 2017
    Last edited by a moderator: Sep 7, 2017
    Thanks for everything everybody.

    I have 1 final question. She's 98% back together and runs great with a fresh motor. However - I have a short ground strap leftover that for the life of me I do not remember removing. Can anybody show me where it goes? It's not the large braided one on the abck of the gearbox, this one is smaller diameter.
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