Drfixit Posted January 21, 2009 Report Share Posted January 21, 2009 Obviously my battery is not charging, my first clue was when I turned on the headlights and the engine died! Measured voltage and got 10 volts whether it was running or not. So I know its not charging how do i tell if its the alternator or voltage regulator besides swapping them out? I am assuming I have a stock externally regulated alternator. If I need to I can post some pics of my setup. For now I just charge the battery every couple days and try to get home from work before dark LOL. Quote Link to comment
datzenmike Posted January 21, 2009 Report Share Posted January 21, 2009 Make sure the regulator is firmly screwed down so it is well grounded. Also make sure you have a ground strap from the negative terminal to the body sheet metal. When you turn the key to on does the RED charge light, light up? Does it go out when you start the motor? Quote Link to comment
Drfixit Posted January 21, 2009 Author Report Share Posted January 21, 2009 The red charge light never lights up at all. Strap from negative terminal of........Battery?Voltage regulator? I had this great idea to check out my fantastic Haynes manual and they have entire section dedicated to alternator troubleshooting. It says due to the specialized nature take it to someone who is qualified to repair it. WOW glad I bought that book!! LOL Quote Link to comment
datzenmike Posted January 21, 2009 Report Share Posted January 21, 2009 (edited) The bulb must be blown. It should light in the on position so you know the bulb is OK. Hmmm see if the two wire plastic plug is firmly pushed into the back of the alternator. Yeah, there should be a thick black wire running from the negative terminal to the sheet metal body... could even be connected to one of the screws holding the voltage regulator to the fender. And yeah again! How can they charge money for a manual with a chapter on automatics that shows how to check the fluid... but anything else it says: "Due to the complexity of the automatic transmission unit, any internal adjustment or servicing should be left to a Datsun agent or automatic transmission specialist".... right like I'm going to Mr. Transmission. Those guys have found a legal way to print money. Edited January 21, 2009 by datzenmike Quote Link to comment
ggzilla Posted January 21, 2009 Report Share Posted January 21, 2009 Measured voltage and got 10 volts whether it was running or not.Yep, voltmeter is the best way to test this. Test Regulator: 1. Clean batteries cable terminal. Scrape both cable ends and battery tops clean. 2. With engine running, jump the F wire on the alternator to battery +, for a few seconds: * If the voltmeter still reads 10 volts, the alternator is bad * If the voltmeter goes up to 13.5-15.0 volts, the alternator is OK. Check out the regulator wiring (replace regulator if the wiring looks OK) Bad alternator is often just the brushes, about $5 for new ones. Quote Link to comment
hang_510 Posted January 21, 2009 Report Share Posted January 21, 2009 autozone load tests them for free :D the VR is usually all or nothing, so if your see low volt, the ALT would be my 1st suspect. Quote Link to comment
banzai510(hainz) Posted January 21, 2009 Report Share Posted January 21, 2009 I think you can disconnect the VR and if the voltage goes above 15-17 volts(it will be unregulated,jumpeing around ) that mean the alternator is good and the volt reg is Bad But as above if low its usually the alternator. Be honest if I was new into Datsun I would do the Saturn alternator on a 510. I dont know who rebuilds for Napa, But i guess we will find out how good they are. But I have to many Nissan units to still use up. Quote Link to comment
racerx Posted January 21, 2009 Report Share Posted January 21, 2009 Before you buy a new alternator, have Kragens or autozone or whereever you are buying it. Installed one in my Datsun and it still did not work, changed the voltage regulator and still did not work. Brought the alternator to another auto store and it was bad. Got a new one from Kragens and fired right up. Quote Link to comment
Drfixit Posted January 22, 2009 Author Report Share Posted January 22, 2009 Thanks for all the advice. Ill tear into it this weekend. I have heard about a one wire alternator? What the hell is that? Just one wire to hookup? Quote Link to comment
a.d._510_n_ok Posted January 22, 2009 Report Share Posted January 22, 2009 On older alternator systems if you start the vehicle, disconnect the battery cables and the car keeps on running it's (usually) not your alternator. Quote Link to comment
510er Posted January 22, 2009 Report Share Posted January 22, 2009 Thanks for all the advice. Ill tear into it this weekend. I have heard about a one wire alternator? What the hell is that? Just one wire to hookup? yes er um yea sort of... Search Saturn, or saturn alternator on this site and you will find lots of alt infor... shit did it for you http://forum.ratsun.net/showthread.php?t=9093&highlight=saturn there you go pretty easy, i did mine for less than 50 bucks:eek: Quote Link to comment
Drfixit Posted January 23, 2009 Author Report Share Posted January 23, 2009 Ive read a bunch on the saturn alternator switch. If it is my alternator, well hell really almost no matter what it is I am going to upgrade the charging system. The saturn route seems pretty foolproof. And hey thanks for the link........... Quote Link to comment
gpcdatsun Posted January 23, 2009 Report Share Posted January 23, 2009 I know a kool place in Downtown LA Ca. that takes the old one and rebuilds it at what ever amp you need. If you need I can get info, but your probably too far. Quote Link to comment
banzai510(hainz) Posted January 23, 2009 Report Share Posted January 23, 2009 Dude if your not going to run extra electrical stuff just get a stock 35amper. the bigger alternator needs mods 35amper Nissan 23100-U0100R from Nissanparts.cc If still avail?????? and get a solid state volt reg when possible from carquest or maybe auto zone,The solid state ones. the SaturnAlternator is NICE and I will suggest people do those now esp in 510s as there is more room. You can have a local shop rebuild yours but see if nissan still has these. This is not hard just change it out!!!!!!!!But the local parts stores I have had crappy lucj with them not lasting to long Quote Link to comment
Drfixit Posted January 24, 2009 Author Report Share Posted January 24, 2009 I am going to check today to see whats available. Having a local shop rebuild what I have but with more amps sounds like a good plan. Think I'll check that out. Quote Link to comment
Drfixit Posted January 24, 2009 Author Report Share Posted January 24, 2009 Well Im in the poroces of working on it today. VR loks like new almost, not getting 12 volts to either of the coils in the VR although there is 12v present, tried closing the relays by hand and still no jump in Volts, took off the disconnected the battery and it dies immediately but I already kinda knew that. Found a 10 gauge wire, black in color coming out of the wiring harness with the other alternator wires. It has a forked type connector on it and is spread likeit came out from under a nut. Im looking up the wiring diagram to see what it is. I thought it would be a ground but it has 12volts running through it. Quote Link to comment
Drfixit Posted January 24, 2009 Author Report Share Posted January 24, 2009 (edited) Ok the big black wire is for the oil pressure sending unit. The wire colors coming out of the alternator are Red.....Blue......Green........White with black stripe. I dont see any T like I have read in other posts now I am not sure that the alternator ever worked. The wiring bundle had been all taken apart by the alternator like someone was doing something. I am going to get a couple pics and see what you guys think. Maybe this is not a stock setup. Hell they changed to an L18 engine so anything is possible. I could rewire the whole deal if I knew what the wires coming out of the alternator were. The red wire from the alternator matches up with a ground wire in the truck plug and the blue wire matches to the plug that has 12 volts off the ignition key. Wouldnt you think red would be the 12 volts from the key? [/img] This is the alternator that is on the truck [/img] This is the truck side of the plug. I always hear others talking about the stock "T" plug for the alternator. I guess this isnt one? [/img] This is the unit all plugged together. Any ideas how I can determine what the wires that goe into the alternator are supposed to be hooked to? I am thinking maybe they made their own plug or something. The white wire on the lug on the alternator goes straight to the battery side of the starter. There must be a way to find out which wires are what on the alternator.Ideas???????????????? Edited January 25, 2009 by Drfixit add photos Quote Link to comment
datzenmike Posted January 24, 2009 Report Share Posted January 24, 2009 Doesn't even look like a Nissan alternator. Quote Link to comment
Drfixit Posted January 24, 2009 Author Report Share Posted January 24, 2009 (edited) Thats what I was afraid of.There is a metal plate on the alternator but you cant read anything at all on it. Does the plug (Truck side) look correct? If so maybe geting a rebuilt alt made to fit the L521 will work? I just read an article that stated 90% of all car manuf excite the alternator with 12 volts through the idiot light. Mine is burned out so maybe??????????? Well shit, I replaced the bulb and now the Ign light stays on so I guess I am going to have to find an alternator with a wiring diagram so i can hook it up properly. If only I knew what alternator I had or how to check to see what wires are what. Oh well having a blast workin on my Datsun thats what I bought it for anyway. Thanks for the Help Edited January 24, 2009 by Drfixit Quote Link to comment
ggzilla Posted January 26, 2009 Report Share Posted January 26, 2009 Is that an Hitachi symbol on the back of the alternator (same symbol as on the carburetor?). Four wires coming out seems unusual. Quote Link to comment
ppeters914 Posted January 26, 2009 Report Share Posted January 26, 2009 Is that an Hitachi symbol on the back of the alternator (same symbol as on the carburetor?). Four wires coming out seems unusual. Could be a roadster alternator. Sure is fun figuring out what ya got, ain't it? :fu: Quote Link to comment
Drfixit Posted January 27, 2009 Author Report Share Posted January 27, 2009 Dont know. Its dark, cold and snowing so it will have to wait till another day. Quote Link to comment
Drfixit Posted February 24, 2009 Author Report Share Posted February 24, 2009 Finally took the alt and VR to a shop and they tested it. Alt is shot. Having them rewind it so I can just slap it back on and it will be a good alt and more powerful too. Quote Link to comment
dat521gatherer Posted March 3, 2009 Report Share Posted March 3, 2009 is the f wire on the alternator the thick yellow one with the eye hole and not the plug with 2 wires? Quote Link to comment
Drfixit Posted March 4, 2009 Author Report Share Posted March 4, 2009 is the f wire on the alternator the thick yellow one with the eye hole and not the plug with 2 wires? The F wire is a seperate terminal on the alt and it hooks to the starter. Not sure what is what but i got it all back, put it on and it works so it must be hooked up right!! Quote Link to comment
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