355 - 94 ROW F355 Major Electrical Troubles | FerrariChat
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355 94 ROW F355 Major Electrical Troubles

Discussion in '348/355' started by sfcarguy, Jul 9, 2024.

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  1. sfcarguy

    sfcarguy Formula Junior
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    #1 sfcarguy, Jul 9, 2024
    Last edited: Jul 9, 2024
    So long story short, at some point someone decided to hack up the wiring harness in and around the fuse box in the footwell of my F355 in a poor attempt to remedy a failing fusebox.

    The car is at my local independent and they are trying their best to make sense of what's going on but so far have been unable to sort the wiring harness. The tech's and I both have @Qavion's full set of diagrams for the car plus the lackluster documentation from Maranello.

    Initial symptoms were poor running and misfiring/backfiring and not revving past 4k RPM. Turns out the fuel pump for one of the banks wasn't running and thus it was only running on 4 cyls.

    Any help/diagrams/pictures/info is appreciated.
     
  2. Qavion

    Qavion F1 World Champ
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    #2 Qavion, Jul 9, 2024
    So what's the car doing now? If the fusebox is failing are you now looking for a new one?

    If you have photos of the hacked up wiring, that would help. At least we could see what the wire colours are and what they affect. Is it possible to trace these wires to the rear of the relay panel?

    Here's a random shot of the back of a LHD relay panel, but without a lot of headscratching, I couldn't tell you if it's a 2.7 car.

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    Some wiring may look like it's hacked up on the 2.7, but it actually isn't. It's related to the provisional immobiliser wiring. A plug goes nowhere and there are fuel pump-related jumper wires on it (green/yellow and pink/yellow wires). Hacked up wiring may also be signs of a car fitted with an aftermarket alarm which someone removed.

    I don't think any photos from my car would help as it's a RHD 5.2 spider.
     
  3. sfcarguy

    sfcarguy Formula Junior
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    #3 sfcarguy, Jul 9, 2024
    This is one of the connectors. They pushed the wire through the footwell back into the trunk to get a better look at it. You can see how it was cut and spliced in multiple places with inline fuses added. I will ask for more photos.

    I think the car had an aftermarket alarm on it bc there was a Bosch pamphlet in the manuals, but the consensus is that the wiring mess is more than that.

    They found someone to rebuild the fuse box and in the meantime are working with a usable but also melty matching core to try and sort the wiring. Right now I think the car is non-running as they are digging into the harness.

    I’ll be speaking with the head honcho tomorrow to get a better sense of where they’re at. It’s been almost 8wks and not much progress so far.
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  4. Qavion

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    #4 Qavion, Jul 9, 2024
    Last edited: Jul 9, 2024
    So those plugs are not ABS or HVAC related (wrong wire colours). I don't recognise that fuseholder (red/red/brown fuses?). That black plug doesn't look like it comes from the relay panel.

    Here's what the wiring in the frunk should look like

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    Your wiring:

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    Perhaps you can tell us how many slots (pin positions) there are in the black and white plugs.

    (EDIT: I thought the black plug was the one I was talking about earlier, the provisional immobiliser plug, but I've just found a photo of that and it's white). Thanks to @cedrik911

    Unless the 94 model had a black plug.

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    Wiring diagram for that plug (59302):

    https://www.dropbox.com/t/awk5VOR8y3aVMust


    Why they were pulled through the bulkhead, I don't know.
     
  5. sfcarguy

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    #5 sfcarguy, Jul 9, 2024
    I was told that particular bundle of connectors was in the footwell with the relay panel but was pulled into the bulkhead to better examine. The wires were spliced and fuses added to "remedy" the failing board. It's a total mess.

    I will ask for lots of pics tmrw.
     
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  6. sfcarguy

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    #6 sfcarguy, Jul 10, 2024
    @Qavion Do you have a diagram of the footwell relay/fuse panel specifically? I have your folder of charts for my ROW 2.7 organized by each system, but I don't see anything of just the ins and outs of the relay panel. That would be really helpful if you have that.

    More pics coming soon.
     
  7. Targatime

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    #7 Targatime, Jul 10, 2024
    There are lots of good used wiring harnesses for sale, taken out of wrecked or parted-out 355's, and they're not expensive. OP, I would look at just replacing the bad harnesses rather than spend who knows how much $$$$ paying a shop an hourly rate trying to figure out what's wrong with your current fuse box and harnesses and poring over wiring diagrams and tracing wires. Just R&R with good harnesses and move on with your life.
     
  8. Qavion

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    #8 Qavion, Jul 10, 2024
    Last edited: Jul 10, 2024
    In theory, you could attach an aftermarket immobiliser to the provisional immobiliser connector (at least to disable the fuel pumps). Maybe that's what the PO tried to do.

    I don't have any theories on the white plug yet. I can't find anything which fits it at the moment. Maybe some closeups/wire colours will help. Maybe it is aftermarket?

    Nope. Perhaps Guido @theunissenguido has one? He maps the internals of Ferrari boards e.g.

    https://www.ferrarichat.com/forum/posts/147753723/

    If he has, that would confirm your board is faulty. Unfortunately, they don't show what the ins/outs do.

    All you can do is make a chart from all the individual diagrams. I tried to do a 2.7 Vs 5.2 chart (using my car), but the wire colours on the back of my panel were too hard to see.

    https://www.dropbox.com/t/BDQbjnuCXc1psOX4


    Anyway, I would start with the power hungry circuits, fans and fuel pumps, found on the cooling and ignition diagrams.
     
  9. Qavion

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    #9 Qavion, Jul 10, 2024
  10. Qavion

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    #10 Qavion, Jul 10, 2024
    Disregard that photo in post #2. It's a 5.2.
     
  11. Qavion

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    #11 Qavion, Jul 11, 2024
    How sure are you of this? Could it just be someone adding an aftermarket alarm and then deleting it (when it failed)?

    I put together this pinout for the F355 2.7 Euro relay panel backplugs:

    https://www.dropbox.com/t/6bVHccGWg5cJ4yjw

    Link expires in 6 days.

    Thumbnail (a bit hard to read):

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  12. Qavion

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    #12 Qavion, Jul 11, 2024
    Last edited: Jul 11, 2024
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  13. yelcab

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    #13 yelcab, Jul 11, 2024
    Ian, that is tremendously useful information.
     
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  14. sfcarguy

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    #14 sfcarguy, Jul 11, 2024
    1994 wiring harnesses are slightly different to later 2.7s from what I'm told. And even so, it's not quite so simple to find an actually good harness. Most dismantlers just hack the harness out of the car, and many have either been flooded or on fire at some point.
     
  15. sfcarguy

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    #15 sfcarguy, Jul 11, 2024
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  16. sfcarguy

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    #16 sfcarguy, Jul 11, 2024
    It is far beyond just an alarm. The whole fusebox was torched and every connector has been royally messed with. Endless weird wiring BS and splicing and add-a-fuse galore.
     
  17. Qavion

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    #17 Qavion, Jul 11, 2024
    jeez...

    Unfortunately, not all of these wiring harnesses are broken up into manageable chunks. You'd have to pull the whole car to pieces to install new ones. Each plug on the fuse/relay panel seems to feed 10 different systems. I think I'd be repairing them too, rather than replacing them.
     
  18. sfcarguy

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    #18 sfcarguy, Jul 11, 2024
    I'm told that this is a lock cylinder that spliced into the harness... I mean wtf... Clearly remnants of an alarm immobilizer something install.
     
  19. sfcarguy

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    #19 sfcarguy, Jul 11, 2024
    The right side DME isn’t waking up correctly (hence why it was only running on 4cyl and their was no fuel pressure for that bank). They've been swapped left to right and the issue doesn't follow, so there's clearly an issue with the aftermarket crap that’s hacked into the harness.
     
  20. Qavion

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    #20 Qavion, Jul 11, 2024
    Reminds me of my car before I mostly sorted it... Lots of dodgy repairs and bizarre wiring mods. Fortunately the wiring harnesses were relatively cheap and available at the time and all accessible during my first major.

    Specific issues like this should be easy to diagnose, but you'd need a working relay panel first. A wire tracker sometimes comes in handy for the DIY-er.
     
  21. sfcarguy

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    #21 sfcarguy, Jul 11, 2024
    "Should" being the operative word. Fingers crossed.

    I am not DIY-ing this. Major electrical problems like this are well beyond my comfort level (and patience). The techs who I've entrusted the car with were struggling with the lack of available info, but I've sent them your fuse panel diagram and hopefully they can get a better sense of what's what now.

    They have a working (albeit also melty) core to get the harness sorted while the actual panel is out being rebuilt.
     

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