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Picked up a neglected early build 1979 recently, where someone swapped a 1982 electronic ignition(poorly) into it with an MSD blaster 2 leading coil. The car will start up pretty much no problem. The motor runs fine at about 1400, but it stumbles badly under 1400 then dies when it gets even lower. I ran it today and started to adjust the idle speed and mixture(it was running so rich my eyes burnt) and after placing an inductive spark checker on the wires, I come to find that neither of the leading wires are firing, as well as no fire or discharge out of the leading coil. Here are some details:
All connections were cleaned and dielectric’d.
Tested leading and trailing coil resistance, both check out fine.
Tested to make sure neg/pos terminals on the coil were connected to the neg/pos on the igniters. Both trailing and leading checked.
There is 12v present at the + of both coils when the key is in the on position
The tach in the car while jumpy, works(accuracy unknown)
New Cap
New Rotor
New plug and coil wires
New plugs
I've checked all the normal things that I would normally check in my other old cars in a no spark situation except for these igniters. These are unique to the rx7 as I understand it.
Would the next step be to test the leading igniter?
Also after reading the ignition swap tutorial, the external resistors should be bypassed? And there is a relay under the front driver’s headlight that only allows it to fire under certain circumstances, should that be unplugged to allow the trailing to fire all the time?
Swap the leading and trailing igniters.
If the problem goes to the trailing side, its your igniter.
If the igniter is bad on the trailing side this may also disable your fuel pump and tachometer, at least it did on my stock 84 12a. Hook up your timing light on the trailing coil to dizzy and just crank the engine. If the igniter is dead you will not get any flashes.
Well hell! Your battery isn't hooked up! That's the problem right there!
In all honesty though, I would check the igniters. If the leading one is bad, you can get away with swapping it for the trailing one. Your car will run without the trailing plugs firing. There is a thread on here that explain how to swap the Mazda Exclusive and Elusive J-109 igniters for run of the mill GM igniters. I'd recommend that route since the J-109's are about $300... The GM ones can be picked up at any auto parts store for about $15.
Thanks for the replies guys, I appreciate it. So it sounds like my next step is to just swap the leading/trailing igniters and see if the leading fire while the trailing don't.
Yeah I saw the GM igniter retro fit, great stuff.
Should the trailing relay be disconnected, as well as should I be using the external resistors with the 82 distributor swap?
Thanks for the replies guys, I appreciate it. So it sounds like my next step is to just swap the leading/trailing igniters and see if the leading fire while the trailing don't.
Yeah I saw the GM igniter retro fit, great stuff.
Should the trailing relay be disconnected, as well as should I be using the external resistors with the 82 distributor swap?
Not that I'm aware of. It should be fine to just swap igniters and go for it. It shouldn't cause any problems in the 5 seconds it takes to crank and check for spark. If the igniter is bad, GM retrofit. cheapest and quickest way to go.
Ok so I took the igniters off the car and tested both of them using the directions I found on this forum. Very strange, the leading igniter tested OK and the trailing igniter tested bad. Yet my issue is that the leading coil not firing and the trailing coil working fine. I didnt have a chance to swap them on the car yet.
Could it be that whoever swapped in this 82 distributor, that somehow the leading igniter is firing the trailing coil?
I guess I'm going to peel back all the electrical tape and check how its hooked up. Is this diagram really all I need?
Yep! You'll see the top of the Dizzy tells you where the plugs/wires go. The easiest thing to do would be to swap igniters, it only takes a second to pull the dizzy off and move them around. There us a way to bypass the igniters short term, but I'm entirely sure what the process is or entails. But that's the diagram! I'd recommend downloading the service manuals if you can. I printed them off at work, free paper/toner.
I have the cap plug wires going to the correct spots I'm sure of that. I guess my question is how do I know that the leading igniter is firing the leading coil and the trailing igniter is firing the trailing coil?
It seems how its set up now, the leading igniter is firing the trailing coil.
If you have an ohm meter you can test for continuity from the igniter to each coil to see if they are inverted.
However the plugs on the igniters and leads on the coils are color coded.
Blue is trailing and White is leading.
The leading igniter is toward the radiator.
The trailing igniter is toward the right side.
But your system is no longer stock and the color coding may not apply.
Today I retested the connections from the igniters to the coils and found strange results. Both male spade clips coming out of both igniters are continuous to the + and - on both coils. So basically no matter which points I probe, my meter will always beep for continuity which I realize is now not right.
You need to completely verify all that wiring. The ignitors mounted on the shock tower in the
picture look odd to me. Not stock from what I can see. Not sure what resistor you are speaking
of but normally none needed.
Personally, I'd rip it all out and start over using HEI ignitors and TFI coils but I'm biased that
way.
I don't have igniters on the shock tower, they are mounted on the distributor. Those white ceramic looking boxes on the strut tower are external resistors.
I agree I need to go through the wiring. I might just convert to the GM igniters with dual leading coils.
I don't think you need to be hooked up to the resistors. You should be able to remove those wires. The igniters are on the distributor. Look up the wiring for an '84. It's using the same setup, minus the resistors. Shouldn't be too hard to remove them and take them out of the system. I'd have to look at mine and take pictures, but I'm deployed and not with my car... :'( If you're going to go with 2 leading coils, just go direct fire. You'll need 3 GM igniters instead of 2, and 3 coils instead of 2.
Ok so I undid all the electric tape etc. From the wiring diagram it looks like I will have continuity from the negative side of each coil to the negative male spade on each igniter.
It seems like the positive side of either coil will have continuity to BOTH igniters?
The igniter facing the radiator is leading. Which spade would run to the negative of the leading coil?
You need to make sure the connector on the negative side of the coil is disconnected from the coil. Otherwise, both connectors on the igniter plug will show continuity.
Thanks for the further clarification, I appreciate it. I have the negative on the coils disconnected. The leading igniter terminal C has continuity to the negative on what is hooked up as the trailing coil. And the trailing igniter terminal C has continuity to the negative on the leading coil.
It seems to me that the clips on the negative sides of the coil are backwards. In essence the coils are flipped. Sound plausible?
Ok I swapped the coils around so the leading ignitor is hooked up to the leading coil and trailing to trailing. The trailing ignitor is bad, but now when the motor is running the leading coil is firing and so are the leading plugs.
The car still does the same thing. I start it with choke on, it high idles fine but once the choke kicks off I have to keep my foot on the gas. When it gets around 1000 it starts to stumble then dies promptly after that.
I'm thinking maybe gunked up idle circuits? Any suggestions?
Are you running a Nikki or aftermarket carb? I'm pushing a Weber DCOE, my idle mixture was off. I turned up the idle screw so I could get it to idle, then messed with that mixture screw until the RPMs leveled out. It's still not perfect, but idles around 850-900. I'd say to tune the carb and go from there.
It's a stock Nikki. The guy I bought it from said that the car sat for a few years before I bought it so I have to imagine it sat with fuel in the car for a while. I took out the idle speed and mixture screws and gave a healthy dose of carbs cleaner. I understand Nikkis are sensitive to varnish buildup. Could that be my issue?
Being that I don't have a Nikki, I couldn't say for certain, but it definitely sounds plausible. I'd also check your fuel filter and screen inside of the tank. They could very easily be clogged causing a starvation problem.
Thanks for the suggestions. I put a brand new metal canister fuel filter in and the fuel level is half way on the sight glass when the car is running so I don't think it's a starvation issue. I'm leaning towards the idle circuits being nasty from sitting, which is why it runs fine above 1000 but dies immediately under.
I checked the base timing by rotating the motor(by hand?) and lined up the leading timing mark and checked the distributor rotor orientation. It looks fine.
I checked all the lines but I guess it could also be a pretty big vacuum leak?
I agree. I was going to do it at some point but it looks like it might have to happened sooner. I searched the forum, some people recommend the Atkins rebuild kit, some recommend this kit from AutoZone, or should I just call my Mazda parts department? Who makes the best rebuild kit?
08-02-16, 07:54 PM
