so, I removed the alt belt, tried to start and it wouldn't start at all, I put the belt back on, removed the ground wire I rigged, tried to start it and nothing! the choke wouldn't hold and the fuel pump wasn't working, it did start for a second, and when I sprayed starting fluid, but wouldn't run at all for the most part. i suspected the fuel pump, but with the choke not holding also, it seemed like part of the system wasn't getting power. fiddled around with the wiring a bit, checked the fuses, all good, worked the switch on and off to try to start it and eventually the choke caught and it started, still ran bad, with tach and backfiring problems, but it idled kind of ok. at that point I tried again to run it without the alternator but it would barely run at all, and when it did the tach was still pointing at the 13v position and it was also bouncing some. so I put the belt back on and ran it til it warmed up, and gave up.
I have all the ignition stuff ordered and on the way, but I'm convinced the problem is much deeper, and at this point with the pump/choke power going out like it just did, I'm reluctant to drive it at all until this get sorted out.
these electrical gremlins are driving me nuts! WAY beyond my pay grade

 

Sounds like an electrical issue .

 

thanks genius, I thought you said it was the gas cap?

 

Wow, this sounds maddening. Gut sensation is there must be something going on with wiring damage or internal component damage with the ignition components that's causing some of that static you experienced. But from what you just described, there could be problems with the alternator or ignition switch as well

Few things you might be able to try to check for or rule them out:
-Multimeter on the terminals to see exactly where your battery sits with everything off, running with alternator working, etc. You might have mentioned it, but it's gotten a bit fuzzy
-Could also get alternator tested at an auto parts store
-Disconnect alternator and run engine with jumper cables to another car that's running, essentially depending on the helper car's alternator
-Bypass ignition switch, could be jerryrigged with a 30a toggle switch for now and a button for the starter

I'd also try the external tach suggestion. The fact that the tach also still worked with the wire disconnected from the coil gives me the sensation that there's some wiring weirdness going on

 

do the SAs use fusible links like the FBs do?

 

Yes

 

well, for what it's worth, my brother's car (an '83) started doing some random, weird electrical things on a road trip about 12 years ago or so. i never suspected the fusible link until i stopped to get food and when i came out the whole car was dead. i went to pull it and as soon as i touched it, the power came back. i fired it up and drove it straight to a parts store and got one of those "upgrade" fuses. the lesson i took from that experience is that they apparently can screw things up without actually breaking.

mind you, from what i remember it did not have all the symptoms you describe, but i figured it's worth a look.

my other 2¢ is you should go through all the alternator (and related) wiring with a fine-toothed comb.

 

what are the values and placement for the fusible link replacements? i've looked for the thread and can't find it. this might be a good time to do the upgrade, even though mine tested with good continuity.

 

The Factory Service Manual shows the fusible link values in x.xx f. Here is the translation.

1.25=45 Amps
.30=20 Amps
.50=30 Amps
.85=35 Amps

https://www.rx7club.com/1st-gen-arch...-532866/page2/

https://www.rx7club.com/1st-generati...source-272447/

https://www.rx7club.com/1st-generati...k-help-246537/

 

pulled the alternator, checked out ok at autozone, battery voltage 13.3v by itself. running was 14+volts, so should be good. after studying the wiring diagrams and consulting an electrical engineer friend we agreed the problems point to the ECU ground as a possible cause. the problem is we cant find it. does anyone know where the ECU ground is on an SA?
ECU fuse was good, connector, circut all looked good
picked up fuses for fusible links, will install later

 

The 1979 (SA) doesn't have an ECU like the FB, There is an Emissions Control Unit on the drivers side kick panel.

The 1979 also has an external voltage regulator on the drivers side rear fender.

https://foxed.ca/rx7manual/manuals/1...ingDiagram.pdf

 

That's what i'm talking about, the emissions control unit seems to be common to all the systems that are acting up.

Is the voltage regulator in the luggage compartment? I'm not seeing it on the diagrams

 

The voltage regulator is on the drivers rear side inner fender just under the hood by the brake master cylinder. It's a squirish block.

 

not sure how the regulator would be an issue, if the battery is charging properly?

 

Based on your numbers it OK.

 

The ignition parts came today, so I installed them one by one, running the engine after each thing, plugs, wires, cap, after the points were installed the problem was gone. the old points looked ok, had a good gap,but were slightly pitted, so that combined with the low fuel pressure and rotor slipping just compounded things. all pretty simple stuff. it still needs a little fine tuning, but I"m looking forward to doing some driving this fall.
I think I had so much difficulty because of two things 1. a tendency of mine to over-think things I don't really know enough about and 2. a resistance to me doing as I'm told and taking shortcuts (which was why I never joined the military).
feel free to chide, throw shade, ridicule, etc. me. I deserve it for not doing the obvious things first, and falling into a rabbit hole of theories. so thanks to everyone particularly KCrepu for your help and patience

 

I have found that over the years in the military, and out, that I learned more from my "mistakes" than anything I got right the first time.

 

Congrats man, that's what this forum is really about. Knowledge sharing and keeping this platform alive. I cannot tell you the number of times I've literally said "thank god" out loud when finding a thread from years past that is exactly the problem I've been having. Someone may stumble on this thread in searching for their problem and learn something too.

 

Are you sure it wasn't the gas cap?

 

Ha Ha very funny 😂 . But my gas cap was the cause of poor running conditions. Whoever owned the car before was using a vented cap and that's why my car ran like dogshit after it sat for a while . I changed plugs , points , rotor cap , plug wires , checked timing etc. All made the car run better but my mysterious issue never went away , car would run like crap hot or cold If i hadn't driven it the day before and it would suddenly run well after half an hour or after I would shut the car off for 5 mins once it got warm .

My car still occasionally runs like **** but it's almost always the carb or dirty fuel filter , My tank has rust in it that builds up over the year , but no more undrivable bucking after changing my gas cap .

 

Just poking a little fun.....I wonder if hitting the old points with a fingernail file, might have de-glazed them and helped the issue before changing them out. I remember my dad doing that back in the day. I've done it to the contacts in the headlight relays before, when one would stop going up or down.

 

it ran good today, but I tried to take it out again tonight, and the choke/fuel pump circuit went out again. I tapped on the fuse block out of desperation, and it started working, then died again when I got in the street, tapped on the fuse block again and I could see sparks flashing in the dark, got a flashlight, fuses were all good, couldn't really see any sparks or residue, engine fuse looked ok but replaced anyway, seems to work now, will take another look at it tomorrow.

 

My friend has told me just cleaning them with a clean dollar bill of any denomination should remove residue. The cap and rotor actually exchange material through the arc of electricity and that material build up causes issues. So yes you are probably 100% right . That's why it's important to lube connectors up with electrical grease to prevent corrosion and glazing .

My dad just bought a few thousand tools from a estate sale for dirt cheap and as i was going through it several packs of " Ignition point files" were among the mess. They seem to be old ( 1970's) so yes , back then people did that !

 

removed the fuse block today, it looked good, nothing frayed, loose, burnt, or otherwise. put it back and replaced all the fuses with new ones. I hope this is finally the end of this thread

 

yeah, but the points were only a couple bucks, still I would've thought tune up parts would last longer than 5k miles. I did have to adjust the points at least once before when they wore down. It makes me consider doing a swap with an electronic distributor, so I don't have to deal with these problems.