Ozzie831 Posted June 14, 2014 Share Posted June 14, 2014 Hello I have just got my 77 280z running a few days ago after its been sitting for about a year and a half (Turbo-ing it). Since it sat so long i had bought a new Altima Import 60 AMP alternator and Super Start battery (700CCA) from Orileys near the end of the build. Towards the end of the build there has been a lot of starting and stopping of the car so i kept it hooked to a charger most of the time. After i got the car tuned a little bit (about a few months ago) my clutch started to slip and I broke a bolt on the water pump....... So i took the entire engine out and redid the timing chain and all that jazz since i was already in there. Got it all back together last week and got the car started a few days ago. I started driving around a bit to break in the clutch and the car started two act a little weird. Yesterday I had driven about 1 mile away from my house to pick up some chinese and i couldnt get it to start, the battery was just too dead. I had to get a jump from a guy that worked there and the car died again while i was driving home (luckily it was downhill so i just coasted home). So today i bought a volt meter and the battery was about 11.32v when the car was off and 12.23 with the car on. So I took the alternator and battery back to Orileys and had them tested. They both passed. So when i got home i tested the battery and it was at 12.6v. I re-installed everything and turned on the car to see if i had hooked everything up correctly and then turned it off. I rechecked the battery and it was at 12.48v, which i though was a little odd. So i checked it with the car running and it went DOWN to 12.32v...... then i rechecked the volts with the car off and it went back to 12.48-50 Im not very knowledgeable when it comes to this kind of stuff but isnt the voltage supposed to go up with the car on? like to the 13-14ish range? If anyone has any input, it would be greatly appreciated. Austin. Quote Link to comment Share on other sites More sharing options...
Lazeum Posted June 14, 2014 Share Posted June 14, 2014 (edited) It seems to me something was off with your alternator. It was a good move to have it checked. If the battery is still able to hold its charge, it should be fine. O'reilly tested it so I would put it out of the picture. Alternator regulator should hold tension around 14V if it is charging. On my 240z, the regulator is not part of the alternator, so it seems to me you haven't checked it yet if it is not part of the alternator. So it could be a reason. 2nd alternative could be a loose belt. It is not tight properly, alternator could have not been run properly leading to malfunction. it should also be the correct size; somehow, previous owner on mine had different wheel sizes between water pump, alternator and pulley. I had to run 10mm wide belt ; too small for water pump but good for pulley - it was slipping. I now have a different pulley, belt is now 13mm wide, it fits perfectly, there isn't any slippage anymore. To make sure, I would plug a voltmeter on the battery while car isn't running, check voltage, start the car and see if voltage changes. You should read 12.5V not running and around 14V when running. You might want to rev a little in neutral to see if voltage changes while you're at it. Edited June 14, 2014 by Lazeum Quote Link to comment Share on other sites More sharing options...
Domzs Posted June 14, 2014 Share Posted June 14, 2014 Test as stated in the above but also check at the alternator output/charging wire too . Quote Link to comment Share on other sites More sharing options...
Six_Shooter Posted June 14, 2014 Share Posted June 14, 2014 Test as stated in the above but also check at the alternator output/charging wire too . I was just going to suggest this. It's possible that the alternator is fine, but the connection between it and the battery is not. I don't recall if the '77 280Z has a fuse-able link for the alternator or not, if it does, this is likely where the problem is. Quote Link to comment Share on other sites More sharing options...
Ozzie831 Posted June 14, 2014 Author Share Posted June 14, 2014 (edited) Thanks for the responses. Ill have to go take a peak at some of those wires. Lazeum: The belt is fine, i looked at that as well. When I tested the battery after i re-installed everything we did rev it a bit and it did go up from 12.32 to 12.48-ish. Ill also take a peek at the voltage regulator thats behind the fuse-able links I was thinking about the fuse-able links myself but there a bit of an enigma to me. There's 3 red wires and 1 black one. I read somewhere that the black wire was the one that passed the power throughout the engine. I was thinking of doing this to get rid of the fuses http://atlanticz.ca/zclub/techtips/fusiblelinks/index.html. Edited June 14, 2014 by Ozzie831 Quote Link to comment Share on other sites More sharing options...
NorwegianZED Posted June 14, 2014 Share Posted June 14, 2014 A good alternator should charge around 14V, I would say an absolute minimum should be 13,5V. Normaly they are labeled 14,8V. If this is the case, I would check; cable from alternator to battery, AND engine grounding back to the battery. I had problems with the alternator and regulator so I trew them both out and bought a newer alternator with an internal regulator(easier to wire up) it should be easy to find one that fits. If the battery holds its charge over night I would call it good, you can test it yourself, if you sort it with a spanner or something while you measure the voltage and the voltage doesn't drop below 10-11V it is fine, don't take to long with this if you decide to do it. If the car dies while you are driving and you stil meassure 12,3volts on the battery I would think the problem is elsewhere... Quote Link to comment Share on other sites More sharing options...
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