I have a 1980 with electronic ignition. At some point, it has had an engine swap to what appears to be an 81-85 12A, due to the lack of a thermal reactor and what appears to be a later engine bay wiring harness (connectors going nowhere, oil pressure sensor in oil pan). I mention this, in case its germane to solving my question.

The 7 hasn't been driven for several months, but it started fine this summer. I've been doing some rust control under the battery tray, so the 7 has been disabled until today. I've changed all the plug wires, cap and rotor, and pulled the plugs and cleaned them.

The problem I'm having is that I'm not getting spark to the plugs, and to the best of my knowledge to the cap. I've ohms checked both coils, and they read around 1 ohm (good, considering its 30 degrees here). I've done the Mazda shop manual test for the igniters (wiring up the test circuit), and they tested fine.

I need to know where to look next. I'm not sure of what feeds the igniters. The wiring diagram looks like it shows inputs from the ECU and the ignition switch, but I don't know what voltage I'm looking for and when (cranking?).

Also, my understanding is that the tachometer should jump around while the engine is cranking, but mine stays flat. This is probably an indicator that voltage is not getting to the coils when cranking, which leads to the ignitors, which leads to...?

Thanks for any help. I need the 7 up tomorrow, and I'm still working on it tonight, so don't wait until tomorrow to answer on my account =).

-dave

 

what kind of shape is your battery in,,,,i understand the 7 needs a good battery especially in winter,,,,,

 

check the fusible links

 

You need to insure that you are getting 12V to the coils when the key is in the "ON" position first.

 

Battery is, of course, being jumped. Fusible links have been checked for continuity. I am not getting 12V to coils when key is on or cranked, assuming I'm supposed to check across the terminals.

 

Oh, and I ohms checked the magnetic pickups in the distributor. They're fine.

 

i know it is for an 85, but maybe it can help you. it was a link given to me that helped me. i now have fsm's for 80, 83, 84.
http://www.wankel.net/~krwright/cars/rx7/85_manual.html

 

I have the 80's manual, but the 85 is laid out better. Thanks.

 

no prob. it helped me so i figured it could help someone else. good luck. i'll check back to see what you come up with.

 

If the coils aren't getting 12V when the keyswitch is in the ON position, the problem is most likely in the ignition relay, or the keyswitch itself. Check at the switch and verify that you have 12V present at the IGN terminal.

 

Thanks, Wankel. I'll work from there.

 

i think Wankelguy is the person who sent me the link for that fsm. he knows what he is talking about and is trustworthy, listen to him!

 

I'm not the one who sent you the link you mentioned, but I appreciate your kind words. -Mike

 

The problem is solved, but I don't know why =). I checked the circuit from the IGN switch to the fuse box, then from the fuse box to the coils, with good results. I then opened the igniter box, looked around, swapped igniters for the hell of it, and put every back together. I turned the key, and my timing light lit up. I then commenced a happy dance.

Now, I know swapping the igniters looks like the obvious fix, but remember I checked them according to the procedure laid out in the Mazda FSM, and they passed with flying colors. However, I would like to know how to check to see if the trailing igniter is working. I've checked the trailing plugs for spark, and they're good, but I wasn't clear if this was the same as checking the trailing igniter's function.

 

That's because you did more than one thing at a time.
Still, it's good that you got it going. I suspect that you just had a corroded connection either on the fuse block, or the ignitor. Electronic troubleshooting is best done one step at a time, that way when you actually find the problem, you can point to it and say "Ha! You bastard!"
Then if it ever happens again, you know right where to look. Good job, anyway.

 

Thanks for the pointers, Wankel. I used to be an electronics tech several years ago, just needed a friendly push in the right direction to get the troubleshooting juices flowing. I sure felt silly after you pointed out to check the 12V from the IGN, but I appreciate it.

My guess was a bad ground, so we're probably spot-on. Electrical is a fussy mistress.

 

Great point, wankel. I can't count the number of times I've had to remind myself to change one variable at a time when troubleshooting something. Normally, that means code (as in computers) but it applies equally to cars and anything else that doesn't work.

Anyway, hammmy, glad to see you've eliminated the problem.