SoCal Jet Boats

Tech Talk => Engine Mechanical / Electrical => Topic started by: tahiti mike on May 18, 2007, 11:20:41 PM

Title: alt problem
Post by: tahiti mike on May 18, 2007, 11:20:41 PM
here we go.when my alt is plugged in it charges great.only prob engine wont shut off. when not plugged in shuts off just fine.also running a crane fireball .any help would greatly be appreciated . this is making me crazy
Title: Re: alt problem
Post by: hotrod56cars on May 18, 2007, 11:26:25 PM
GM three wire altenator, right?   ;D
Title: Re: alt problem
Post by: tahiti mike on May 18, 2007, 11:27:56 PM
yes it is
Title: Re: alt problem
Post by: hotrod56cars on May 18, 2007, 11:43:15 PM
Is it wired like this picture?
Title: Re: alt problem
Post by: tahiti mike on May 18, 2007, 11:44:29 PM
yes and it wont let the frikin engine shut off
Title: Re: alt problem
Post by: hotrod56cars on May 18, 2007, 11:49:05 PM
 I'll be back....
Title: Re: alt problem
Post by: tahiti mike on May 18, 2007, 11:53:32 PM
it has the red comming from battery to the back of the alt.small red wire going from plug to back of alt. and one white wire from plug towirring junction block
Title: Re: alt problem
Post by: hotrod56cars on May 19, 2007, 12:02:46 AM
There's a larger wire on the altenator's post (red), the smaller ed wire goes to the larger red wire. Those two wires I just wrote about are the furthest apart. The white wire (in between the two red wires) goes through a idiot light and then to the ignition. Does your system have an idiot light? If not, I don't know how else it could work. The light has to be good in order for it to charge.

I have also seen it where a person hooked up the + coil wire to the smaller red wire on the altenator which went to the igniton, his engine wouldn't shut off.
Title: Re: alt problem
Post by: tahiti mike on May 19, 2007, 12:07:19 AM
goes through a gage
Title: Re: alt problem
Post by: hotrod56cars on May 19, 2007, 08:08:15 AM
I was told once that GM made an altenator that looked exactly the same for car's that came with a gauge but I've never been able to wire a GM altenator through agauge and get it work. If you get it to work I'd like to know how it's wired.

But the problem is that the engine won't shut off. When you're turning your key off the coil isn't losing power like it needs to. Other than the diagram I'd have to be there to help you out further. You can temporarily wire in a light and see if the problem goes away. If it does go away then you know you need to get rid of the gauge or wire the gauge up differently. If it doesn't go away the altenator is wired wrong.
Title: Re: alt problem
Post by: tahiti mike on May 19, 2007, 09:06:25 AM
ill give a shot
Title: Re: alt problem
Post by: HDriderTH on May 19, 2007, 11:26:13 AM
You need a diode on one of the small wires on the Alt. cant remember which one right now but could find out at work Monday. MSD actually supplies one w/ there stuff. Anybody have MSD installation instructions? Online maybe?
Title: Re: alt problem
Post by: tahiti mike on May 26, 2007, 02:31:23 PM
well i added a diode that crane said to use and it still wont shut off. need in put
Title: Re: alt problem
Post by: sandaddict on May 26, 2007, 04:52:27 PM
is the diod goin the right way.  they are one way diods designed not to let the alt. backfeed to the coil.just a thought ;D
Title: Re: alt problem
Post by: tahiti mike on May 26, 2007, 06:05:33 PM
sure did shuts off fine on the trailer.put her in the water wont shut off.making me crazy
Title: Re: alt problem
Post by: The Chaz on May 26, 2007, 07:49:19 PM
That is indeed strange.  I can't think of any reason floating in water would be any different electrically than sitting on the trailer.  Water leaked into the bildge and is shorting something out?  I had the 3 wire one and kept getting shorts.  I have a red light mounted in the dash that controled it.  I just switched to a single wire one from jet boat performance.  Problem solved ;D
Title: Re: alt problem
Post by: sandaddict on May 27, 2007, 12:23:04 AM
sure did shuts off fine on the trailer.put her in the water wont shut off.making me crazy

WTF!!! ???
Title: Re: alt problem
Post by: HDriderTH on May 27, 2007, 10:54:37 AM
on a diod there is a stripe, the current goes in the direction where the stripe is closest to the end of the diod, i beleive the current is exiting on that end
Title: Re: alt problem
Post by: tahiti mike on May 27, 2007, 02:37:00 PM
DID THAT INSTALLED THE ONE CRANE CAMS SAID TO USE WITH THERE FIRE BALL INGTION.WENT TO BERRESSA YESTERDAY .WOULDNT SHUT OFF ON THE LAKEUNLESS THE ALT WAS UNPLUGED.PUT ON THE TRAILER SHUTS OFF JUST FINE NOW.MY TAHITI HAS GREMLINS.
Title: Re: alt problem
Post by: hotrod56cars on May 28, 2007, 08:26:37 PM
DID THAT INSTALLED THE ONE CRANE CAMS SAID TO USE WITH THERE FIRE BALL INGTION.WENT TO BERRESSA YESTERDAY .WOULDNT SHUT OFF ON THE LAKEUNLESS THE ALT WAS UNPLUGED.PUT ON THE TRAILER SHUTS OFF JUST FINE NOW.MY TAHITI HAS GREMLINS.

Gremlins indeed! I'd love to get my hands on those Gremlins, err electrical challenges.
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