240zprace Posted December 5, 2003 Share Posted December 5, 2003 my ride is a 72 240zt.i bought a 280zx alternator(internal voltage regulator). the new alternator is installed in my car already. now i know the plug that plugs into the external regulator gets stripped and reconnected to one another. but i don't know which wire to whicw wire.please help me on my wiring to whom has done this upgrade on the early z. thanks... Quote Link to comment Share on other sites More sharing options...
Guest bastaad525 Posted December 5, 2003 Share Posted December 5, 2003 I just did this same swap a few weeks ago... luckily there were a few guys on this forum that pointed me where I need to go for the directions You need to bridge two pairs of the wires from the voltage regulator connector together for this swap to work. One of them is just bridged and the other one needs a diode in line with it. You dont even really need to cut or strip anything if you dont want to. There is a much easier and faster way to do it. For one of the pairs, just make your own jumper wire... take a short piece of wire, like 2-3", and crimp male spade connectors on both ends (okay I lied... there IS some cutting and stripping involved here... DOH!). The male spades will fit perfectly into the openings on the end of the connector that used to go to the voltage regulator, and they are spaced widely enough apart that you really dont need to worry about them touching each other or anything. The diode you need is part #1N5402 (manufacturers part #), or if you want to get it from radio shack, their catalog part # is 276-1143. It costs like $2 for a pack of two. The diode has really long metal 'wires' coming out of each end, like this -----------[ ]----------- I just crimped male spade connectors directly onto the ends of the diode and bent them how I needed, getting rid of the need to soder anything. If you dont use the diode, the car wont stop running when you turn the key to the off position!! Now I'm assuming that you're car is like mine, and has the rectangular connector end with slotted holes... some Z's (later 280's I think) had a round connector with round holes, not that that would keep you from doing it this way, just substitute the round male pin style connectors for the spade connectors. Now here's the lowdown: Looking at the connector that used to go to the regulator, there should be five or possibly six wires going into it. You only need to worry about four of these. First, you need to bridge the plain white wire, to the plain yellow wire (though on my car the wires were so aged that they both looked yellow !!!) using the jumper wire. Then you're going to use your diode to bridge the black w/white stripe wire, to the white w/black stripe wire. Now, the diode has a greyish stripe on one end of it, you want that end with the stripe to go into the white w/black stripe wire. Dont worry if you get this wrong it wont hurt anything. The diode acts like a check valve, allowing current to only flow one way... what happens without it is the alternator will keep back-feeding current to the ignition system causing the car to keep running after being turned off. The one or two wires left on the connector you dont need to do anything with. After I bridged bridged the wires, I wrapped electrical tape around the the two pair seperately to cover up any exposed metal and then wrapped tape tightly around the whole thing... it doesn't look bad at all, it only took me about 10 mins, and since I didn't cut anything it'd be very easy to go back to stock if I ever wanted to (I know... why??). Another method would be to cut the connector end off of your voltage regulator (find a spare at the junkyard if you want to do this) with a couple inches of wire still on it and splice the two pair together using that... just seems more of a PITA to me. Anyways, as for the rest, I'm sure you already know that all the wires on the back of the alternator hook up exactly the same... just fire it up and enjoy the extra amps! Quote Link to comment Share on other sites More sharing options...
240zprace Posted December 5, 2003 Author Share Posted December 5, 2003 bastaad 525 thanks for the info, greatly appriciated i,ll try it today and let you know how it turned out. ----------------------------------------------------------- 72 240 zt,stock l28et motor,t3/t4 hair dryer,intercooled 6 puck w/sprung hub,bushing kit,all suspension redone 15psi-daily driven demon 18-20psi-when called upon Quote Link to comment Share on other sites More sharing options...
orklc Posted May 26, 2005 Share Posted May 26, 2005 First my apologies for resurrecting such and old topic. But I need to understand what is happening on my son's car. I just spend a few hours doing the maxima 90-amp upgrade on a 71 - 240z and it appears to be working as anticipated. I am reading 14.4 volts at the battery on idle and I am able to turn the key off and the engine shuts off. I have eliminated the external regulator in the 240z and bridged the yellow and white wires as indicated in the explanations as well as installed the diode across the white/w black stripe and the black /w white stripe wires. The gray band on the diode is on the white w/ black stripe end as required to eliminate the feedback to the ignition circuit. The other connections are also done as specified. White/red to B, black wire to E (ground), White/black to L and Yellow to S. The car feels find, until I decided to re-check the mounting bolts, and I noticed that the pulley is magnetized and my tools are being attracted to the pulley even with the engine being off and not running. Is this Normal? If the alternator is energized while the car is sitting it will probably run down the battery, correct? Any ideas as to what is going on and what I need to do about it. I disconnected the battery and the alternator releases as I expected. Any suggestions? Ken C. Quote Link to comment Share on other sites More sharing options...
Guest bigbadzcar99 Posted June 8, 2005 Share Posted June 8, 2005 I tried the 100 amp GM one wire alternator upgrade about a year ago because i was sick of the lights dimming at night when the engine was at idle. I removed the external voltage regulator using the directions on the sight and spliced the wires, and low and behold...fried all the wiring from the alternator to the battery to the starter and half the fuse box. It took me about a month of tinkering and lots of swearing before i got the wiring all sorted out. I lerned form this that if Mr.K wanted a higher amp alternator on an early Z, he would have put it there himself. Now i run the stock alternator, and with all the new wiring and better connectors, the charging system works just fine. Quote Link to comment Share on other sites More sharing options...
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