mazdaverx713b

iTrader: (91)

During my diagnosis of the poor running condition on first startup in my 80, I noticed that I no longer have a warning light bar that's illuminating and my voltmeter has stopped working. All lights do work and all gauges on the cluster are working properly. Does their function run through the main relay? I don't have a 1980 wiring diagram handy and I'm trying to get both issues solved asap. Any help would be very much appreciated!

UnregisteredSA22C

I know that the ebrake/brake fluid warning light connects the brake master cylinder, e brake switch, and the pin on the back of the gauge cluster because I've had problems with it before. I'd say that any electrical diagnosis will probably require a wiring diagram though. You can find full factory service manuals online in pdf. The fact that all the warning lights are out, and not just one, might help you narrow down the problem. Sorry that I don't have anything more useful!

Roland

Toruki

Wiring diagrams are here:

Foxed.ca - Mazda RX-7 Manuals

Edit: Oops, just noticed that you are mazdaverx713b and that you know where the manuals are.

t_g_farrell

iTrader: (1)

You need to look at the check and sumthin relay over by the clutch master on the fender. It inputs some control for the voltmeter and warning lights.

mazdaverx713b

iTrader: (91)

That's what I was thinking. I think its the check and cut relay . I'll give that a look tonight and check the wiring and the connector for corrosion.

mazdaverx713b

iTrader: (91)

No worries at all. The scanned wiring diagrams are hit or miss for me. I have a 1980 FSM and wiring diagram....somewhere. Its not in my library of RX-7 manuals where it should be so I figured I'd make a post and see if anyone had similar issues. You can also use RotaryHeads.com - Rotary Engine Mazda RX8 Renesis RX7 Turbo Wankel 13B Rebuild Parts for the manuals. The owner of that site has them nicely organized.

Toruki

Thanks for that link...just spent an hour looking!

mazdaverx713b

iTrader: (91)

Finally getting back on this. The voltmeter is still inop. I'm getting warning lights for add coolant, which comes on and fades quickly fasten belts which remains illuminated. I replaced the choke and check relay with another and the issue still persists.

NCross

iTrader: (18)

Sounds like you have a problem with your leading ignition coil. Try another coil, and make sure the - terminal is clean and tight (in particular the YG wire). Tach / volt meter gets signal from the - terminal of the leading coil so if your tach is inoperative and it runs rough sometimes (may be related) I would at least start there.

mazdaverx713b

iTrader: (91)

The tachometer works just fine. The voltmeter is inop. It takes 5 minutes to change a coil so I can toss another one in there. The engine hits a brick wall and the idle bounces up and down extremely rapidly a few hundred rpm for a few minutes if the throttle is touched at all when the engine is started. If you're not touching the throttle it will idle just fine. I have not been able to figure the issue out as of yet.

mazdaverx713b

iTrader: (91)

Just wanted to follow up on this. I was working on the car yesterday and found that the issue was that the two pin plug that connects to the alternator was not making good contact with the alternator. I cleaned the connections and plugged it back in and the voltmeter and warning lights are working properly.

Banzai

iTrader: (13)

Glad you found and solved your issue. Little electrical gremlins like this can be so elusive and frustrating to track down. On to the next one.....

mazdaverx713b

iTrader: (91)

Yes they can. The next one for this car is when the engine is warm and restarted it will idle fine but when you give it gas it cuts out like its out of fuel. If you let off the gas it will idle perfectly. Once it idles for a couple minutes it will rev perfectly fine. Cold starts there is no issue. What a pain, lol.