ComicArtist Posted April 9, 2012 Share Posted April 9, 2012 (edited) Started having this problem last night. My battery died, so I put another fully charged one in it. It ran fine for about five minutes, then the car died. Checked and the battery was dead again. So I assumed the alternator wasn't putting out voltage, changed the alternator, and jumped the battery to start it. However, after that, if I ran the headlights, the car would sputter and die. This morning, I had to jump it to start, didn't even turn on the headlights and the car drove for a couple of minutes, the voltage gauge started dipping, car lost all power, began backfiring through the intake, and died completely. This is in my '78 by the way. All stock engine wise except for a wire tuck and battery relocation. Any suggestions? This is my dd, I'm stranded on the way to work and I have no clue. Also, the charge light on my voltage gauge is on. From what I've read, it means there's a problem with my charging system somewhere but I haven't had any problems until now. Also, the alternator I switched it out to last night is off an '82 zx L28. I thought they were the same internally regulated as the '78, but I could be wrong. Edited April 9, 2012 by ComicArtist Quote Link to comment Share on other sites More sharing options...
ComicArtist Posted April 9, 2012 Author Share Posted April 9, 2012 Been reading the schematics of an L28 alt for the last hour, my reasoning is that there's a short somewhere between the positive output of the alt and the battery. If this was so, then the car wouldn't be charging the battery, which would mean the car would only be running off the battery. Which would then cause the car to run on low voltage, slowing down the fuel pump and the injector pulse, as well as all the issues caused by lowering the voltage to the ECU. ^ which would cause the intake backfire. Now, to my knowledge, the output wire from the alt goes to the positive terminal on the battery, but my question is how? The only thing I have the battery running to is the starter. None of the fusible links are blown, so that rules out that problem. Just wondering, would there be any negative results to just jumping a wire from the positive output on the alternator straight to the battery, eliminating that circuit? I'm about to try it. Gotta use a heavy gauge wire, probably like a 8 or 10? I think the wire coming off the alt is like a 10 already. Quote Link to comment Share on other sites More sharing options...
Six_Shooter Posted April 9, 2012 Share Posted April 9, 2012 The charge terminal of the alternator is usually connected to the starter's battery terminal. Running a wire from the alternator's charge terminal to the battery's positive terminal is fine. I like to use no less than 8 AWG for this connection. Quote Link to comment Share on other sites More sharing options...
ModernS30 Posted April 9, 2012 Share Posted April 9, 2012 I rewired my entire alternator system. You should have a little white wire that bolts down to the positive terminal on the starter, this connects to the alternator, which means that it connects to the battery. Do the Maxi-Fuse upgrade that is on Atlantic Z Car, one of the best mods I've ever done, besides just the cleaning up my bay it is nice to not have those sketchy fusible links anymore and I feel like I've got a more solid connection. Quote Link to comment Share on other sites More sharing options...
ComicArtist Posted April 9, 2012 Author Share Posted April 9, 2012 I did the maxi fuse conversion about 3 years ago lol, big improvement. But the fuses/relays that were all located on the passenger side engine bay are now relocated to the inside of the firewall on the passenger side. Cleans up the engine bay and is still located in a fairly convenient spot. I didn't have a wire running straight from the alt to the battery, I'm guessing the white/red wire coming off the alt goes to the 80a fuse, which then goes to the battery. Looks like my problem was a bad alternator AND battery, causing no good at all. I'm going to be late to work but hopefully the parts will be in at O'Reillys in an hour or so. Quote Link to comment Share on other sites More sharing options...
MexiChriS Posted April 17, 2012 Share Posted April 17, 2012 I did the maxi fuse conversion about 3 years ago lol, big improvement. But the fuses/relays that were all located on the passenger side engine bay are now relocated to the inside of the firewall on the passenger side. Cleans up the engine bay and is still located in a fairly convenient spot. I didn't have a wire running straight from the alt to the battery, I'm guessing the white/red wire coming off the alt goes to the 80a fuse, which then goes to the battery. Looks like my problem was a bad alternator AND battery, causing no good at all. I'm going to be late to work but hopefully the parts will be in at O'Reillys in an hour or so. Did you finally for sure figure out what was the problem? Been a week, just curious to hear your outcome Quote Link to comment Share on other sites More sharing options...
ComicArtist Posted April 25, 2012 Author Share Posted April 25, 2012 Well, went through the wiring harness, got a new alternator, bypassed my aftermarket fuse block, still had the same problem. But found out yesterday while this riced out Civic was trying to pull on me (I may or may not have responded), that over 5k rpms the alternator kicks on. My voltage was low as usual, around 10-11 volts, and as soon as I hit 5kish, shot up to 16 volts. Had a voltage tester in the car, and since my battery is currently in my passenger side floorboard, I tested it and came out at 14 volts. Tried this a couple other times during the day, and worked as well. Basically, when I turn my car on, my alternator isn't working. As soon as I rev up, it kicks on. Weird huh? Quote Link to comment Share on other sites More sharing options...
Pharaohabq Posted April 25, 2012 Share Posted April 25, 2012 Sounds to me like something's not wired right with the field wire on the Alt. When you swap in the ZX Alt, I think there's supposed to be a diode added. Right off I don't remember if it's to the field wire, or another, but I remember having to put one in on mine. Quote Link to comment Share on other sites More sharing options...
ComicArtist Posted April 25, 2012 Author Share Posted April 25, 2012 It's not running a ZX alt now though, part number is for a '78. Quote Link to comment Share on other sites More sharing options...
Randall Posted August 20, 2012 Share Posted August 20, 2012 not sure if you figured out the problem but i think the lower connector on the plastic "T" fitting tells the alternator to charge at idle and low revs so it may not be getting a good connection. Your sense wire ( top of the "T") may have a bad connection also. As this tells the alternator how much it needs to charge. Dont know for sure but from the research i have gathered to fix my problem that sounds like a good place to start Quote Link to comment Share on other sites More sharing options...
Zmanco Posted August 20, 2012 Share Posted August 20, 2012 Started having this problem last night. My battery died, so I put another fully charged one in it. It ran fine for about five minutes, then the car died. Checked and the battery was dead again. So I assumed the alternator wasn't putting out voltage, changed the alternator, and jumped the battery to start it. Without a dead short (which would be very obvious due to sparks, heat, etc) there is no way a fully charged battery will discharge enough in 5 minutes such that the engine will die. Most modern batteries are rated to run the car with headlights on for more than an hour. The problem is something more than just a failure to properly charge the battery, or your fully charged battery wasn't. Have you verified that the wiring is all in good condition, with no splices or junctions that are frayed, corroded etc? All the symptoms you describe could be explained by that. Start with the wires between the battery and starter, also check everything between the alternator and the fuse block. Look for ground wires connected to the chassis that are corroded. FYI, I had a similar situation where sometimes the alt would not charge after the car was first started for a few minutes and then after reving the engine it would charge properly. Turned out one of the wires to the connecter under the alternator was frayed where it met the crimp to the connector. Replacing that solved my issue. Reving the engine was a red herring - it was a loose connection that had nothing to do with engine revs. Quote Link to comment Share on other sites More sharing options...
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