bhermes Posted March 12, 2012 Share Posted March 12, 2012 I am new to this forum and have been using another for this topic. The other forum has and is doing a great job but thought I would try here as well. I have owned my 76 280Z for about 1 year and driving it short distances, 6 miles, daily. About once every 3 weeks the car would stall during driving and after about 30 minutes would restart. I suspected rust in the gas tank and that might still be an issue; however, a new possible issue came to light. I installed a new radio in the car in December and noticed that at rpms around 1500 the radio would shut off. I tested the voltage at the battery and found at idle (1000 rpms) it was about 13.8V. Good. At 1500 rpms about 17V. Not good. About 3 months ago a mechanic had replaced the alternator, I also replaced the alternator about 8 months ago, a new voltage regulator and a new battery were also added about 3 months ago. After about 50 posts on the previous forum we decided to replace the voltage regulator again thinking maybe it was bad. I installed today and no improvement. Additional info; With the external voltage regulator unplugged I got 11.6V at battery regardless of the rpms. I beleive that this means that the alternator was not working. The car ran great around the neighborhood but I am guesing the battery would soon die. Any help would be appreciated. Quote Link to comment Share on other sites More sharing options...
bhermes Posted March 14, 2012 Author Share Posted March 14, 2012 Nobody have anything to add? I see a lot of viewings but no responses. I can not think of anything else that would cause this issue. Quote Link to comment Share on other sites More sharing options...
NewZed Posted March 14, 2012 Share Posted March 14, 2012 With the regulator unplugged, the power to the windings in the alternator is gone. No power means no magnet means no charging. If you got 17 when it was plugged in that means the alternator works. You most likely have a break in the wire that tells the regulator what the voltage of the system is at any point in time (the current voltage, no pun intended). In an internally regulated alternator it would be the S wire. I don't know which wire it is in the external system. The FSM has a good description of how the external regulator works and, I believe, describes which of the wires to the regulator is the one that should be connected to battery voltage. It also has a test procedure for determining if the regulator is working correctly. It porbably has the typical bad/good test and a more involved test and adjustment procedure. You should go through the tests in the FSM and report the results back to the group so there will be something concrete to work with. You will probably find one wire that is dead when it should have battery voltage. Quote Link to comment Share on other sites More sharing options...
bhermes Posted March 14, 2012 Author Share Posted March 14, 2012 Great. I will try. Electrical stuff is not my expertese. I have pulled the FSM and will give it a shot. Thanks. Quote Link to comment Share on other sites More sharing options...
VKLR Posted March 14, 2012 Share Posted March 14, 2012 Let me get the facts straight. While driving the car stalls and wont restart until cooling off for a while? You do not have to jump start to get it to turn over? I'm thinking IF the above is true, there is not a charging issue, look elsewhere. I would look at the ignition system. Possible coil? Quote Link to comment Share on other sites More sharing options...
bhermes Posted March 14, 2012 Author Share Posted March 14, 2012 Thanks. I am not that familiar with the ignition system. A novice at best. Just to clarify a few things. The car is stalling sometimes 1 mile from the house and some times 20 miles after driving. Yes the car will start normally about 20-30 minutes afterwards without a jump. I assume that I have a charging problem due to the fact that my voltage at the battery is getting over 17V at rpms. The radio is shutting off. I thought that this could be shutting down the ignition module. Again a novice at best. Maybe moe than one problem. Quote Link to comment Share on other sites More sharing options...
S30 SPL Posted March 14, 2012 Share Posted March 14, 2012 You should not be up at 17V, this is usually due to a defective voltage regulator. When I had this problem, I decided to switch over to the 280ZX turbo alternator which is internally regulated and has higher output. The work only takes a few minutes. Keep driving around at 17V and you will fry something. Most items are not intended to operate at extended periods over 16V. Modern automotive spec is 18V for an hour and 24V for a minute, I'm not sure what the specs were when this car was designed as I wasn't in the automotive field. Quote Link to comment Share on other sites More sharing options...
bhermes Posted March 14, 2012 Author Share Posted March 14, 2012 I installed a new volotage regulator about 3 months ago and then again about 2 days ago. Neither fixed the problem. I have considered the internally regulated alternator but feel that I have something else going on. Not sure if wiring or grounding would cause over voltage. I also put a new alternator on twice in 1 year and a new battery. The battery was less than a year old. Just not sure of what else would cause the added voltage issue. I am leaning torward wiring but again not a real electical person. Quote Link to comment Share on other sites More sharing options...
DrunkleDick Posted March 15, 2012 Share Posted March 15, 2012 Look for spliced wires or questionable connections between the alternator and voltage regulator. I've had crappy solder connections that worked fine until they heated up, caused an oddball issue, then worked fine when they cooled down. This meant that checking for current was useless unless checked while malfunctioning, something you might want to keep in mind. Quote Link to comment Share on other sites More sharing options...
S30 SPL Posted March 15, 2012 Share Posted March 15, 2012 I don't know where you got your voltage regulators from, but I went through 3 of them from CarQuest back in the day, everyone of them junk. Either high, low or inconsistent. I went through the alternator, all my connections, and when it came down to it, it was always the regulator that was jacked up. Now, with the 280ZXT alternator, the output is stable, makes enough juice at idle to keep the battery charged with accessories and lights on, doesn't kill the battery when driving stop and go on a rainy day with A/C, heater, defroster, lights and wipers on... so much nicer. Quote Link to comment Share on other sites More sharing options...
bhermes Posted March 17, 2012 Author Share Posted March 17, 2012 If I switch to the internally regulated alternator what other changes are required? I saw something fora 240z but does anyone have what needs to be changed for a 76 280Z 2+2? Also, what year 280ZX alternator should I be looking to get? Part? Thanks for all the help. Quote Link to comment Share on other sites More sharing options...
DrunkleDick Posted March 19, 2012 Share Posted March 19, 2012 http://atlanticz.ca/zclub/techtips/alternatorswap/index.html This should cover any questions on the alternator swap. TIP: Use Google to search, this was the first result for "280Z alternator swap". Good Luck. Quote Link to comment Share on other sites More sharing options...
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