BillZ260 Posted January 11, 2008 Share Posted January 11, 2008 OK, so I broke down and bought the new Delco ALT. Read throught the Painless book on how to hook up the 3 wire ALT and it said to hook the wires like this. Bat Post on back 12V Battery Post #1 - Run the Exciter wire #2 - Jumper to the Bat Post 12V possitive. All hooked up and ready to roll, car starts up, volt meter shows 14V now instead of 11! I drive around the neighborhood and all makeing sure everything is fine. Pull into the garage, double check all the guages and then turn off the key...... CAR STAY's RUNNING! First I guessed that my ignition switch had completly failed, so I pulled the wires out of the back and nothing, still running. I got the car to stop by turning in the idle screw a couple times, since I didn't feel like getting shocked when I pulled the coil wire. SO, I get on the net and find several areticlas that state I need to hook up the wires as follows (here's one of the articles http://www.rmahc.com/alternator.html) BATT - to Batt Post #1 - Used to hook to the warning light, if the alt fails it acts as a ground. #2 - Used to Excite the Alt, can be hooked to the excite wire OR to a jumper to the Bat Post. This is basically the OPPOSITE from what the Painless Book states. Do you guy's have any input? Quote Link to comment Share on other sites More sharing options...
Six_Shooter Posted January 11, 2008 Share Posted January 11, 2008 What you are experiancing is the alternator feeding back into the ignition. I'm not familar (yet) with the starting and charging system on the S30, but I am very familar with the GM starting and charging systems. The stud on the back of the alternator is the charge stud and must be connected to the battery. In older GMs this stud was attached to the starter batter terminal through a fuseable link, newer GMs it is attached to the underhood fuse box through a fuse to the main battery input terminal. The Red wire is a "sense" wire that the regulator uses to sense the actual charge voltage to adjust the alternator output. The best place to connect this is also to the battery or same connection point as the main charge lead (starter battery terminal on older GMs). The brown wire is what turns the alternator "on", and is usually turned on through a "charge" light, the light in the guage cluster that shows your actualy charging. This needs to be through an ignition switch wire that is NOT the true ignition wire. Partly so that it isn't trying to charge while starting, but mostly so that the car does not run on like you are experiancing. You can as a quick fix insert a 3 amp diode in this wire with the line in the direction of the alternator. This will keep any power from back-feeding into the ignition system and keeping it powered up. I know on some cars this diode is needed, due to the layout of the ignition switch. Quote Link to comment Share on other sites More sharing options...
Thumper Posted January 11, 2008 Share Posted January 11, 2008 I've read this problem before but can't remember exactly. You need to install a diode to make sure voltage doesn't go the bleed through. I believe its on the sensing wire. Try searching alternator and diode it should come up. Good luck. Quote Link to comment Share on other sites More sharing options...
Six_Shooter Posted January 11, 2008 Share Posted January 11, 2008 I've read this problem before but can't remember exactly. You need to install a diode to make sure voltage doesn't go the bleed through. I believe its on the sensing wire. Try searching alternator and diode it should come up. Good luck. Or look at the post above yours. Quote Link to comment Share on other sites More sharing options...
BillZ260 Posted January 11, 2008 Author Share Posted January 11, 2008 I'll grab a diode at lunch. Still confused between the TWO different ways documented on hooking up the #1 and #2 posts. Quote Link to comment Share on other sites More sharing options...
BillZ260 Posted January 11, 2008 Author Share Posted January 11, 2008 WHULP! Was searching the Painless site and their latest version of the install manual has this new note! It's perfect, includes part number and everything. Thanks guys, should have this fixed soon! * Under some circumstances the connection of the alternator will not allow the engine to be shut off. If this occurs a diode will need to be installed inline on wire #914. This will prevent the alternator from back feeding into the ignition system and thus causing the engine to run with the ignition switch turned off. The Radio Shack part number for the diode is 276-1661. It is to be installed with the stripe towards the alternator. I posted a link to the manual in the painless sticky at the top of this sectionl. Quote Link to comment Share on other sites More sharing options...
Thumper Posted January 11, 2008 Share Posted January 11, 2008 Or look at the post above yours. DOH!!! LOL Glad someone has a better memory than me:flamedevi Then again its been 3 yrs since I played with mine. Good luck. Quote Link to comment Share on other sites More sharing options...
BillZ260 Posted January 14, 2008 Author Share Posted January 14, 2008 Just a follow up post. Diode on the Exciter wire to the Alt did the trick. If anyone needs one, I have 3 more 6A diodes from Radio shack. They sell them in packs of 4... Quote Link to comment Share on other sites More sharing options...
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