Hi everyone!
I just joined the forum, I have used a lot of the threads on there for my first gen that i picked up a couple of years ago. It is a 1980 model with 70k original miles and I am the second owner of the car! Its been a blast to drive and so far the only changes that have been made are a racing beat exhaust and a rats nest delete.

I recently pulled it out of its winter hibernation and it appears that my battery tender got unplugged over the winter. I put a fresh battery in it and it fired right up, however I noticed right away that the tach/volt meter does not switch from showing me the current volts to showing me engine RPM - I.E. my tach sits at around 5K even though the engine is resting at around 800RPM, So I am assuming its still displaying volts.. Along with that the GEN light, Add Oil, and Add Coolant lights stay on. The engine runs fine, there is plenty of oil and coolant, so I am assuming this is as simple as a bad alternator? I am going to run down to the hardware store and grab a multimeter this week, but was just wondering if anyone has experienced these symptoms?

Thank you in advance and I will keep searching the forum for info as well.

 

Maybe but could just be a stuck or broken choke check relay. Heres a thread about it https://www.rx7club.com/1st-generati...m-489374/.When it fails the 80 tach doesn't switch to rpm like it should.

 

Interesting read, I'll test the battery with the engine running and see if its charging - if it is ill check the regulator and choke relay.

 

Just for sh*ts and giggles, I went out to my parts car and pulled its choke check relay off and swapped it in, the issue remains the same. Engine starts fine, choke or no choke used, idles perfectly fine and the GEN, oil and coolant light is on. This time I payed more attention to the volt gauge and it never gets pasted 12 on the gauge. So I suspect the alternator is faulty. Once I confirm that with a multimeter I will get a replacement, reading some posts on this site, it sounds like an S4 alternator is a direct swap into an 80, so ill go that route.

 

I did an S4 swap on my 80 and it really is plug and play. I think I got the alternator new from oriellys.

 

Tested the voltage with the engine running, sure enough it sits at 12V and not charging, took the alternator down to the parts store and it also failed their testing 4 times back to back. I'll have an S4 unit tomorrow, but while I was cleaning up I stumbled on my box of parts I've already pulled from the parts car - found the crusty alternator from that car and put it in, and the lights are off and the gauge swaps to RPMs as it should. I'll still put the S4 unit in, because the spare alternator look like is been underwater so who knows how long it'll last

 

I had the same exact problem with a 80 I was working on. I was looking at everything. Ended up being the alternator. Changed it with a stock rebuild from Rockauto. All the dash lights everything went back to normal.