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battery light again

Discussion in '348/355' started by Saint Bastage, Jul 18, 2009.

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  1. Saint Bastage

    Saint Bastage F1 Rookie

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    #1 Saint Bastage, Jul 18, 2009
    Last edited: Jul 18, 2009
    OK...I just replaced the VR and everything was working fine. Took the car for a long (100 miles) ride to the races. On the way there, I stopped for gas. Upon filling her up, I got back in the car and turned the key, Nothing. Reminicent of a problem I had in the past which was fixed by someone else without telling me what the problem was. After 1/2 hour of cool down, I tried again, she fired right up. Continued the trip and everything was fine.

    On the way home, I accelerated hard and got the Battery light again, this time accompanied by the CEL 1-4 and CEL 5-8. I was still 45 miles out but somehow made it home. Before shutting off the car, i check voltage running, 14.1 volts. Shut the car off and checked voltage, 12.45 volts....WTF. Tried to start the car again with no luck...same Hot start issue.

    Allowed it to cool and tried again, she fired right up. No Battery light, no CEL's. Pulled the CEL codes 1122 both sides, (low battery voltage). assumed it was a transient condition and took it for a very short test drive....Battery light at 2500RPM. WTF, WTF, WTF, WTF....


    I Hate electronics
    Any Idea's
     
  2. Saint Bastage

    Saint Bastage F1 Rookie

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    #2 Saint Bastage, Jul 18, 2009
    Last edited: Jul 18, 2009
    manipulated the throttle in nuetral. Battery light comes on at near 2000 RPM. Checked voltage at 1000 RPM, 13.8, 2000 RPM 14.5, 3000 RPM 15.5 volts. Checked the battery terminal connections...tight and clean. Why does the battery light come on when I'm making proper voltage? Why does the car not start when Hot? These issues must be related but Im lost.

    The issue must be associated with heat and therefore in the engine bay...right?
     
  3. UConn Husky

    UConn Husky F1 Rookie
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    #3 UConn Husky, Jul 18, 2009
    Interesting...now I think my electrical knowledge may be the same level as yours...but 15.5V is sounding too high. I wonder if something went wrong with the alternator rebuild and now at higher rpm's you're making too much voltage which is causing the CEL's?
     
  4. Saint Bastage

    Saint Bastage F1 Rookie

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    #4 Saint Bastage, Jul 18, 2009
    Last edited: Jul 18, 2009
    Just found one possible cause.... The last Buttmuncher to replace the battery put in a "maintenance required" type. Found all of the cells low. Filled with tap water and plugged in charger. We'll see tommorrow. At least that makes some sense. A new "maintenance free" Battery will be in the car regardless of this issue.

    I think 15.5 is OK...top of the scale but with this new battery issue uncovered, quite possible. It's trying like hell to charge it.
     
  5. No Doubt

    No Doubt Seven Time F1 World Champ

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    #5 No Doubt, Jul 18, 2009
    Do you have a $6 "Crickit" tension meter? I'd put it on top of the alternator belt to see if the belt was pretty loose. I was surprised to see that tightening the alternator belt up a bit improved the voltage being output on my 928 recently.

    Easy to tighten up the belt a bit, by the way, but a tensionmeter should keep you out of trouble from getting it too tight (which can burn out the bearings on an alternator).

    I'd also double check the main battery/chassis ground strap connections.
     
  6. ernie

    ernie Two Time F1 World Champ
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    #6 ernie, Jul 18, 2009
    Okay now I get it.

    I'm in agreement with what Shemp said. Get under the car and make sure your alternator belt is nice a snug.
     
  7. Miltonian

    Miltonian F1 Veteran

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    #7 Miltonian, Jul 18, 2009
    15.5 Volts is much too high, I think 13.8 to 14.4 is considered the proper range. I would think that pumping 15.5 volts into the battery would cause it to boil out the water/acid, just like you're seeing. If you put in a new battery, and you're still showing 15.5 volts, you still have a problem.
     
  8. gidge348

    gidge348 Formula Junior

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    #8 gidge348, Jul 18, 2009
    Please tell me if I am wrong, but my understanding of the “alternator light” is that it comes on when there is a “Difference” between what is being generated and what is being used.

    If for some reason you had a large current draw at the same time that the alternator was flat out, you would still have and alternator light.

    By the symptoms of no go when hot, good volts from the alternator (possibly too much) I would be looking at the starter motor as a possible culprit?

    Also boiling the battery is a possibility but this may be a symptom of the problem, not the cause?
     
  9. roadracer311

    roadracer311 Formula 3

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    #9 roadracer311, Jul 18, 2009
    15.5 volts sounds high to me too. I had a similar problem with my first motorcycle. It was overcharging (19V). The battery would heat up and the bike would shut down (stranding me far from home). Drawing more electricity by running the high beams helped me get home in that case. Replacing the regulator rectifier cured it. Sometimes regulator rectifiers can fail right out of the box.

    new guy, so I'll give my credentials: I'm not a 355 expert by any stretch, but I own a motorcycle shop and wrench for a living (and not that it's relevant, but I also have a degree in physics).
     
  10. No Doubt

    No Doubt Seven Time F1 World Champ

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    #10 No Doubt, Jul 19, 2009
    Hey! Great first post! Welcome.
     
  11. GeorgW

    GeorgW Karting

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    #11 GeorgW, Jul 19, 2009
    Last edited: Jul 19, 2009
    Hi,

    the regulator should limit the board voltage to 14.5 V, in case of 15.5 V there is something wrong with it. Please consider that too high voltage can damage the electronic devices (radio, motronic ecu a.s.o.) in your car.

    Also the battery light is driven by the VR, so if the light comes on even if the voltage is right then the VR should be faulty.

    Regards, Georg
     
  12. brian.s

    brian.s F1 Rookie
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    #12 brian.s, Jul 19, 2009
    What make and model VR was used? Many threads on this, the output should be 14.5-14.7v max. The battery likely the result not the reason IMO.
     
  13. Saint Bastage

    Saint Bastage F1 Rookie

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    #13 Saint Bastage, Jul 19, 2009
    New information


    Found an old cigarette lighter adapter in my Junk Drawer. Installed some crimps on the leads. Plugged my Multimeter into the crimps, plugged the adapter into the cig lighter. Now I have a voltage meter I can see from inside the car and manipulate the throttle myself. Fired the car and found 13.5 volts at idle and 14.1 at 4000 RPM. Thats better. At least I can see it now.

    I'm now convinced its the battery (but what the hell do I know)
     

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