It wasn't broken, so I just HAD to go and fix it. | FerrariChat

It wasn't broken, so I just HAD to go and fix it.

Discussion in 'Technical Q&A' started by jm3, Sep 27, 2006.

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  1. jm3

    jm3 F1 Rookie

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    #1 jm3, Sep 27, 2006
    I'm the guy trying to find a way to use all the cool new diodes and stuff for the F355 Nippondenso alternators. My alternator was just fine....before I decided to fix it.
    Well the last time I reinstalled it after trying yet another promising regulator lead, I noticed the shock lamp was little dim.
    No big deal says me, it must be the cool new sunglasses. Hmmm...they must be self-darkening lenses, because the light is dimmer now.
    Well, turns out the new (just in case) battery isnt charging. The alternator light is not on, no indication of anything amiss except the voltage is going down like a Hollywood Starlet.

    Has anyone else ever had a charging problem and the light does NOT come on? The stock regulator is in there now. I have one day to fix it.

    Ps the light comes on when i put in the wrong regulator, fyi

    thanks, jay
     
  2. PAP 348

    PAP 348 Nine Time F1 World Champ
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    #2 PAP 348, Sep 27, 2006
    My friend had the same trouble with a Bosch alt the other week. Turned out to be a faulty diode pack in the alternator. :)
     
  3. Steve Magnusson

    Steve Magnusson Two Time F1 World Champ
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    #3 Steve Magnusson, Sep 27, 2006
    The only problem that the alt. warning light system is designed to reliably detect is a broken alt. drive belt. It will often come "on" when some of the electrical bits get frazzled, but it really isn't meant to detect that (bad) condition.
    Keep chewing -- what other option do you have ;)
     
  4. Paul_308

    Paul_308 Formula 3

    Mar 12, 2004
    2,345
    #4 Paul_308, Sep 28, 2006
    Yes, on several different cars. The alternator is a 3 phase machine and when 1 or 2 phases malfunction, the output is curtailed considerably but since it is still charging, if only a bit, the charging light will present a misleading 'OK' condition. Since the alternator's net replentishment output is less than the car's current demand on the battery the net effect is a gradual battery discharge.

    Since most alternator system failures involve not reduced charge but total loss of charge, the common indicator light in lieu of an ammeter is generally adequate.
     
  5. Ricard

    Ricard Formula Junior

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    #5 Ricard, Sep 28, 2006
    I believe that is the most eloquent forum post I have ever read on the internet! ... excellent!
     
  6. PAP 348

    PAP 348 Nine Time F1 World Champ
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    #6 PAP 348, Sep 28, 2006
    Get a room :D
     
  7. Ken

    Ken F1 World Champ

    Oct 19, 2001
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    #7 Ken, Sep 28, 2006
    The industry as a whole has shunned ammeters in favor of volt meters for many years now. I don't understand why except that sending the entire + side load to behind the dash is somewhat of a fire hazard if you're not careful with DIY projects back there (ask me how I know).

    Nevertheless, I like having an ammeter. It has given me warning on two occasions that I was having alternator or battery issues long before I would have been stranded. I also have the red light of course, but by the time it lights up you're already screwed unless you're close to civilization.

    As for your alternator problem, have you tried replcaing the original diodes?

    Ken
     
  8. jm3

    jm3 F1 Rookie

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    #8 jm3, Sep 28, 2006
    The diode pack was replaced with an upgraded one, but the old one is still good.(See title of this thread) I have to take the alternator off and test it. But actually, I am worried this is all a coincidence. I'm getting a funny feeling about the "S" wire, similar to poor old "azferrari". As I check everything, I am not getting any voltage at the plug for S. The Ign works, and L works. I am wondering if there is something funny in the harness. Not a pleasant feeling.

    The 2004 ZinMan from Perry Creek has just been released, and is an excellent accompaniment to troubleshooting.

    Wouldnt it be cool to modify the radio faceplate to display voltage instead of a reduntant clock?

    Jay
     
  9. Paul_308

    Paul_308 Formula 3

    Mar 12, 2004
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    #9 Paul_308, Sep 28, 2006
    FYI - ammeters are actually voltmeters which read the voltage across a known resistance. Properly done, that resistive element is in the engine compartment and the very small voltage goes to the instrument panel. Standalone ammeters have a built in shunt. Ammeters were most appropriate when generators were used, at time before most of the list was a glint in their father's eyes.

    Voltmeters tell a greater story than does a 'charge' light but 'charge' lights have generally replaced meters not only for cost reasons but mostly because few operators are familiar with particulars of lead acid chemistry (for 12 cells) 12.6v at rest...14.4v max charging v. So for the mass populus, voltmeters are marked with green and red areas at those voltages which is tantamount to a charging light.

    Back to the issue at hand, were a voltmeter present instead of a charge light, the indication with 1 working diode likely would be between 12.7 - 13.2 v and not alarm most non-alert operators. The main charge depletion which happened during start would not be replentished in a 10 minute drive.

    I still like a charge light and deal with the 'less than fully charged battery' condition which to me is quite apparent by the sound of the starter when I start the car.
     
  10. Ken

    Ken F1 World Champ

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    #10 Ken, Sep 28, 2006
    1972 technology seems to be different. My ammeter sees a whole lotta amps!

    No doubt voltmeters give some good info; if you see 12 volts while running you know your alternator is starting to quit on you (or some such problem). If you see 15 you know the VR is shorted to ground. But the ammeter will tell you that too, as well as how well the battery is currently holding a charge (by how long it's in the + side upon start up), it will tell you when you have a short circuit, as well as when your alternator is starting to die. And with a practiced eye you can see when your million watt stereo is drawing too many amps. The voltmeter will only tell you how many volts is at the battery. In cars with questionable charging systems and electrics, I'd take an ammeter over a voltmeter any day.

    Ken
     
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  11. jm3

    jm3 F1 Rookie

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    #11 jm3, Sep 29, 2006
    Eureka is the Latin word for "Found It". That’s all the Latin that I know.

    There are a lot of alternator mystery problems on the F355. Do a search for "355 + alternator". Many of these problems repeat themselves, even with new alternators, new batteries, rebuilt alternators etc.

    I believe I have found a (the?) weak point in the system. There is 1 fat and 3 little wires that come out of the alternator. The fat wire goes straight up to the terminal block on the upper left of the engine bay. This is also the jumpstart spot. Three little wires come out of the plug. One goes to the dash light, one is switched on by the key and turns on the alternator, and one is called the "S" wire, and is a small red wire that goes all the way up to the battery.

    This is where I have found a problem. There has been speculation of discontinuity or open circuits in the "S" wire, and it turns out that the wire itself is very well made right up to where the "S" wire joins the battery terminal. Right at the battery clamp, the "S" wire finally rejoins the main power lead to sense (hence the S) the actual battery load.

    This small 1.5mm red wire had corroded and become unattached from the terminal. This fried a diode in the alternator, but any F355 that had a wire starting to fail slowly would exhibit all kinds of weird symptoms.

    So... If you have just finished installing your 5th alternator in 2 years, check the little red wire that is inside the black vinyl tubing, that is around your main battery cable. They are supposed to join together on the battery clamp, just in front of the right front tire.

    JM
     
  12. ernie

    ernie Two Time F1 World Champ
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    #12 ernie, Sep 29, 2006
    Italian wiring strikes again. The wiring in these cars is so bad it is really pathetic. You think we have problems, just wait until the current new cars, with all their electronic this and electronic that, start to get old.
     
  13. flyingboa

    flyingboa Formula 3

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    #13 flyingboa, Sep 29, 2006
    JM, it is not latin, it is ancient greek ... ;) . That brings your latin down to zero. :D
    Ciao
    Eugenio
     
  14. jm3

    jm3 F1 Rookie

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    #14 jm3, Oct 1, 2006
    Well, merde. Whatever language "merde" is from, I'm speaking it now
     
  15. chrisbill

    chrisbill Formula Junior

    Jun 12, 2005
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    #15 chrisbill, Oct 1, 2006
    French... ;)
     

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