Hugh Posted September 12, 2004 Share Posted September 12, 2004 I searched, I couldn't find anything on exactly this subject. Sorry if this is a newb question: My alternator is new, the battery is new. Sometimes it charges fine, sometimes (like tonight) it kills the battery. I got in there and shook the alternator hot wire around... give it a jump, and it works! There's some real problem there, and I want to replace the wiring. (it looks to be 30 year old wiring) The ammeter in the dash doesn't work. It's stuck on the center all the time. I could care less about the gauge, as it will be coming out for aftermarket gauges soon. (Apexi EL 60mm) So how can I completely eliminate that gauge? Can I just run a different hotwire to another spot? (I'm thinking a nice 12 gauge or something like that) I read another thread where someone had run the hotwire to the starter? That I'm not too sure about. Quote Link to comment Share on other sites More sharing options...
Mike kZ Posted September 13, 2004 Share Posted September 13, 2004 I also read on another post of yours that your alt is not charging. Someone said to look for the black fuselink boxes. 240Zs do not have those. But a bad ammeter gauge would do the same thing, your alt would not charge. To bypass the ammeter, you need to connect the 2 thick wires that are attached to it, and make sure you insulate it well! Quote Link to comment Share on other sites More sharing options...
Hugh Posted September 13, 2004 Author Share Posted September 13, 2004 AWESOME! Thank you so much. After going over all the signals in the wiring diagram, I had figured out on my own that I could just remove the gauge and tap the wires together there. I was considering running an entire new piece of wire all the way in, just to replace the 30yr old POS wire thats in there. I will remove bypass the gauge after work today and report back with my results. Thank you! Quote Link to comment Share on other sites More sharing options...
Hugh Posted September 14, 2004 Author Share Posted September 14, 2004 Ok, I rewired the amp gauge out of the system. The big wires headed into it are now shorted to eachother and wrapped up in about 8 layers of electrical tape. I put my Optima battery in the car because the other one was pretty much toast at this point. The Optima is reading 12.4v standing alone. I power up the car, Optima reads ~12.36 Start the engine, and it dropped to ~12.34-12.33 There's definitely no charging going on. I read the alternator from its ground to positive terminal, and it shows like .23v across it. I then tried injecting 12v into the small two wire connector on the back of the alternator (after I figured out which was ground, and which was open.) But this did nothing either. I checked power going into the voltage regulator connector, and the 12v ignition switched power at the black/w wire is not there. I injected 12v, and still no charge to the battery. The Chiltons manual shows a 20 amp fuse inline up the way from this wire, but I cannot find it. This has me really, really confused now. What signal does the alternator need to start producing power? Quote Link to comment Share on other sites More sharing options...
Guest MaXbOOst Posted September 14, 2004 Share Posted September 14, 2004 try your relays ......... Quote Link to comment Share on other sites More sharing options...
Mike kZ Posted September 14, 2004 Share Posted September 14, 2004 Did you change your regulator when you bought the new alternator? I assume you are reading the voltage accross the battery with the engine running right? Are your battery cables new, or cleaned very well? Quote Link to comment Share on other sites More sharing options...
Hugh Posted September 14, 2004 Author Share Posted September 14, 2004 The voltage regulator and alt were already in the car when I bought it. They both 'look' new. There's a guy here in oceanside who offered some brand new parts to try out on it, alternator, regulator and stuff. I'm just really concerned about that ignition 12v not coming into the regulator. I will be meeting up with him soon to try some stuff out, though. The battery cables are not so old. I replaced the negative terminal and added a ground from the alternator to the battery. This made no change. Thats when I realized my alternator isn't making any power at all. Quote Link to comment Share on other sites More sharing options...
Guest 305240 Posted September 15, 2004 Share Posted September 15, 2004 Did you by chance happen to remove the ground cable from the battery to engine ground? If so, did you remember to reconnect the body ground that is in the middle of the cable? If you missed doing this, it will play havic with your whole electrical system. Quote Link to comment Share on other sites More sharing options...
Hugh Posted September 15, 2004 Author Share Posted September 15, 2004 You know, I'm not sure about the chassis ground. Thats an excellent point though... even if its not the solution to this problem, I need to take a look at that anyway. Today I had the alternator tested at Kragen and its fine. The battery is fine. I bought a voltage regulator and that didn't fix it either. At this point, I broke down and brought the car to a professional to fix it for me. I need it back on the road before my 240sx sells. (and its gonna go quick) I just want to drive the car... Quote Link to comment Share on other sites More sharing options...
Hugh Posted September 16, 2004 Author Share Posted September 16, 2004 Car came back repaired..... get this: Three wires were bad or disconnected. Three of them. No wonder I couldn't fix the damn thing myself. The mech spent hours this morning trying to figure it out. He's been working on these cars for 20 years... and this one stumped even him. He did fix it, and it didn't set me back too much. Car charges now!! Whoo hooo!! I think I learned a lot about the ignition system on this little adventure. If anyone has problems like this later, I should be able to help out a bit. SO I'm back on the road and enjoying life. Quote Link to comment Share on other sites More sharing options...
Guest 305240 Posted September 16, 2004 Share Posted September 16, 2004 Glad you are on the road again. There are times when even the best of us have to call for help. It's a good thing there are people out there who can help! Quote Link to comment Share on other sites More sharing options...
Hugh Posted September 16, 2004 Author Share Posted September 16, 2004 Thats what I was thinking. I just wanted to drive it... Quote Link to comment Share on other sites More sharing options...
Mike kZ Posted September 16, 2004 Share Posted September 16, 2004 So where did these 3 wires go that were messed up? Quote Link to comment Share on other sites More sharing options...
Hugh Posted September 16, 2004 Author Share Posted September 16, 2004 Alright, one he said was a main 12v feed somewhere under the dash that was disconnected. I have to look over the schematic to figure that one out. He said my fusable link coming off the battery is gone, and replaced with a wire that is far too small of gauge. He confirmed what I already knew that there's no ignition signal at the voltage regulator. He was going to continue into the ignition problem, but I stopped him and left it at that. In the meantime, I pulled the Ign 12V from the fuse box and ran a hot wire out to the voltage regulator. I guess the fuse I couldn't find is actually in the fusebox, but I think the wire thats supposed to run from there to the voltage regulator is actually bad. (black w/white stripe) I'm going to start systematically rewiring all the important power lines and grounds in the car... Like a backup harness or something. There's just too many wires that are old and brittle or were rewired by someone else who was just plain crazy. But its running great. I drove it to work today and checked my voltage a couple times from the fusebox with my multimeter while stuck in traffic. It's running 13.6-13.8 volts now. Quote Link to comment Share on other sites More sharing options...
Hugh Posted September 21, 2004 Author Share Posted September 21, 2004 Just a little update: The car is still charging just fine. I've been daily driving it without any troubles for the past week. I still have a hotwire jumped into the voltage regulator from the fuse box... I need to check the continuity on the original black/w wire and see if its just disconnected somewhere. Quote Link to comment Share on other sites More sharing options...
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