Hey guy I just got my fist rx-7 it is a 1979 5 speed. It is a lot of fun it is a quick car. My plans are to turn this in to a street car so nothing to much I just want to prove that the amount of cylinders you have does not mean you are the fastest. I have ran in to problems ever day I have had this car the first day it would not idle I then wired the throttle to hold it above 900 rpm. Then the battery died I replaces it took the car got it tested and the alt puts out 30 amp low out put and good diodes. Then in less than 2 hours of sitting it will only click and won’t turn the motor over. I have the battery on slow charge and will put it in the car tomorrow and make sure it still starts. I think it is a grounding problem in the engine bay. Is this common and where is a good place to start looking for the short or does then seem like the problem.
thanks chris

 

Wow, that's a rapid fire post.

Okay, as far as the alternator goes, check this thread in the Archive section on how to upgrade your alternator.
https://www.rx7club.com/1st-gen-archive-71/electrical-s5-89-alternator-install-into-1st-gen-528440/

And, as far as your battery, a bad alternator can drain it, the cells in the battery are going bad, or bad cables. You can replace your battery cables easily and they come cheap, too. I'd just go ahead and replace/upgrade the alternator, battery, and battery cables. Realy easy to do.

And, welcome to the Darkside. Be sure to use the search function and check out this link to download the FSM for your car.
http://www.wankel.net/~krwright/cars/rx7/manuals.html

 

i had just put in a brand new battery for auto zone. And in 2 hours it was drained when i came out. i will put new cables on it tomorrow morning.

 

AutoZone batteries suck. Ive had a couple die in a rather short time and they will give you all kinds of crap before they will warranty them. At least they did with me.

 

I stuck in a Energizer battery from Pep Boys. Good stuff.

But, even then an AutoZone battery should last longer than that. Could be cable problem or alternator. I'd upgrade that wimpy alternator, anyways. They're not powerful enough to handle anything. Check the link I gave you earlier to upgrade.

 

cool i will upgrade the alternator on the 20th when i get payed

 

ok recharged battery went in it cranked over a few time. Then it would not crank any more so i will warranty it out and get a new one and new battery cables. i will report back what happens about 2 to 3 pm central time.

 

Good luck with the "Zone" on the battery! I hope they treat you better than most on the warranty.

 

Replacing the battery cables is easy as pie! Whatever the previous owner was thinking is beyond me. They weren't the best, more like makeshift. So, I had to replace the postive one that leads all the way down to the starter.

THE MOST easiest replacement of cables I've ever done. (Even replacing our starters is a breeze). And, for like $10, you should be able to get new cables for your car. I'd do that at least. Also, get some dielectric grease or Vasoline for your battery terminals. Either stuff will help prevent corrosion.

 

That's one thing I love about FB. It's easy to work on room and access wise.

I had an old 300 zx and it must of had 1000 wires and hoses. You could not work on anything without major hassle.

 

Yeah, they're real pieces of planned obsolescence aren't they.

 

Ok cables and battery replaced (positive and negative cables). It started right up I drove it for 20 min and I will go back down in a bit to make sure it restarts. Battery at turn off was 546cca out of 550cca possible and the voltage dropped from 12.74 to 12.34 and at 3 pm auto zone will have the 80 amp alternator that will be put on. I hope with these done it can work as a daily drive.

 

Ok I just went back down and it will only click it won’t start. I have the battery on a 2 amp charge. The battery is at 12.08 voltage and 256cca. When the car was turned off the battery was at 12.34 voltage and 546cca. The alternator will be in at 2 when it comes in I will install it and see do yall think that will fix it.

 

Better read up about how to upgrade to the higher amped alternator. Plus I believe the 79 RX7's came with an external voltage regulator unless the PO has upgraded it. Never had a 79 RX7 so see if people will respond back and give you some advice.

 

come on guys, there's definately some sort of drain on the bat. when u connected the last cable to the new bat, did it spark? with the engine and ignition switch off, use an amp meter to verify that there's a voltage drain. pull fuses one by one til the drain dissapears. check the box cover for what all is on that circuit and start from there.

 

Is the alt hot?

 

Hey as far as the idle problem goes.......I figured out at least in my car, if I don't run 93octane it won't idle and kinda runs crappy.

 

Hum stock compression does not need super unleaded. It's a waste of $$$.

You might be running too lean or the jet's on carb clogged and not misting well.

Also did you change the fuel filter?

 

Ok guy I have found a fixed the problem it was the starter. The wires from the solenoid to the engine were not insolated. Replaced the started the alternator and the wires and now have a new battery again and the main fusible link and it runs like a champ. No drain of 3 hours. it now fires right up after a few gas pumps and if you sat on it it does not even need that. and for not having power steering it can sure take a corner quick.

 

o ya the alt is putting out 14.73volts average over a 15 min window max 15.1 min 14.2. thank guys for all the help

 

awesome!!

 

Excellent.

 

o ya i will put pics up tomorrow.

 

New fuel filter. Don't know about the carb being clogged? But I do have the owners manual and it says run at least 92 octane and it seemed to help?