12A GSL - Sudden total ignition failure
 

So I'm throwing this up here because you're all really cool people and I can't seem to find the RX-7 ignition diagnostic page that I thought was on here.

I was driving over the santa cruz mountains today on my way into work in my 1985 RX-7 GSL, going downhill in gear with my foot off the accelerator, when I noticed that the tachometer was reading zero. But I could hear my engine turning and I had power braking, steering, etc. So I pushed in the clutch to blip the throttle, and of course, the engine did not pick up revs when I stabbed on the gas, it simply came to a stop, I lost my power steering and power brakes, and my dash lit up like a christmas tree because the alternator wasn't running anymore. Since (I presume) the tach runs off of detecting spark, I realized that I'm not getting any spark.

My wires and plugs were replaced about 4 months ago, when my car was disabled by the leading coil wire sparking to the body. When I was diagnosing that issue I mistakenly thought it was flooded and had put ATF in the engine. When I replaced the plugs, I turned the engine over so that the excess ATF was pushed out. While cranking, I could clearly see (in daylight) sparks arcing from the coils around to the coil mounts (arcing to ground).

While I waited for the AAA truck this morning, I pulled off the coil wires and cranked the engine. I could hear rhythmic clicking that sounded kind of like a spark, but I saw no arc like I had before. I also pulled off the dizzy cap and saw that it was in fact spinning. In doing so, I noticed the cover that is in between the distribution side and the ignition side of the distributor was loose, but that didn't seem to be a problem. My first thought is failed coils or failed ignitors, but it seems almost impossible that BOTH coils or BOTH ignitors would fail simultaneously. If just one component failed, I should see spark from one of the coils.

So now the question is, what do I check? Could there be a short somewhere on the low voltage side of the ignition system? Is there a separate fuse for the ignition system?

Replacing ignitors can get really expensive and I don't think they'd both fail at the same time. My dizzy does spin but my coils don't spark. I'm going to try cranking it tonight to see if I see any rouge sparks anywhere, but as I said, the wires and plugs are about 4 months old.

OK DUMB QUESTION: Is your carb getting any fuel? Is there gas in the tank? Does your fuel pump pump? Sometimes my fuel pump gets lazy and I have to wiggle wires behind the driver seat.

I have original coils from 1985 and an old distributor with igniters from who knows when and they are dependable. I also think it's unlikely that both coils/ignitors failed.

I'd look for wires that might have come undone first. Are your big main grounds connected? Any loose wires between your + terminal and the fusible link block?

Do you get continuity through your fusible links? Those are the big daddies that handle large swaths of the car's electronics.

The shield in distributor is held in place by the distributor cap,it has a specific position to allow dist cap to sit squarely on dist body. When not in place, the clips that hold cap on will attach but cap is cocked and when cranking or running,the rotor is clashing with the terminals in cap and can be the source of clicking you heard while cranking engine. There will be witness marks on cap terminals if this has occurred. This may not likely be the cause of engine shutting off.

The tach not working is a clue you have no trailing ignition. Both the tach and fuel pump are triggered by trailing ignition. The car can run with no spark from trailing ignition,its only function is to clean up emissions, it does need a trigger from igniter to feed tach and fuel pump. As stated,car will run without trailing ignition,until the bowls in carb run dry at which point car shuts off.

Are you taking car to be repaired or trying to fix yourself? Do you have and are familiar with a test light and multimeter? Replacing parts gets expensive fast,not the way to diagnose the problem(s)-there can be more than one.
A couple preliminary things to check to determine which way you need to go to hone in on the reason for no start.

1st pull air cleaner lid and cover from engine and look at both float bowl windows,may need a mirror to see rear bowl window. You should be able to see fuel level in windows,should be at 1/2 way up window. No fuel showing,carb is empty/dry,a clue.If fuel is showing, use the throttle linkage and open throttle @ halfway 2-3 times. You should see a solid stream of fuel squirting into each primary venturi from accelerator pump discharge nozzles. Fuel present in both of these tests would suggest ignition related issue.

2nd,remove all spark plugs and note if damp/wet with fuel or dry. Plugs should have tan/brown coloration. Put each plug back into its respective wire and drape plugs on top of engine for a good ground and have someone crank the engine over while you observe plugs firing.
The color of spark on all plugs should be blue and each plug should fire consistently. Yellow/orange color spark is another clue as are random dropouts or no spark from any of plugs.

Post back your results from preliminary checks. To further diagnose you will need the two tools mentioned previously. I can give you guidance on what to test and in what order to get to root of the problem,without replacing parts unnecessarily,in the process you'll learn more about how your car works.

cpt_gloval it's not a dumb question. But I recently replaced the fuel pump when my original one failed. It's been running great ever since. I have had a clogged carb jet before and it didn't affect the tachometer function, when I was going downhill it still reported my engine rpm, so I'm pretty sure this failure is electrical. If the engine is turning and the ignition system is working it should work without any fuel. I will definitely check the wires when I get a chance.

@GSLSEforme I fix my cars myself. I have 2 others so there's no rush other than missing that rotary buzz. I've done subframe drops, timing belt replacements, that sort of caliber of car work, so I can definitely apply some of your advice here. I just need to find the time. I know how to check the float bowls, I was recently dealing with fuel flow as I thought my aftermarket fuel pump was causing me to fail the smog sniffer test. Turned out to be a missing throttle position switch (as in not installed).

I do have a multimeter. I don't think I have a test light but I know my dad does, so by all means please continue with the diagnostic procedure!

Just to make sure I'm looking at the right thing, where do I find my fusible links?

Fuse links,there are 3,are located near top of left inner fender apron.
They look like gray cloth covered wires,inside them is a wire that will burn thru in event of a short like a slow blow fuse. Test light is quickest,best way to test them.
Ground the attaching clip of test light on negative battery terminal and probe the back side of connector on each end of fuse link. They are in a u shaped loop with one side of its female spade connector attached to feed wire coming from battery and opposite end connected to terminal that feeds its protected circuits,just like a fuse in a fuse box.
There is a main fuse linkthat feeds every thing in the car but starter motor,another that feeds headlight circuit and motors that raise and lower headlamp doors. The third feeds ignition circuit I think,early in morning for me.
The test light should glow brightly on both ends of each fuse link. If one doesn’t light test light on both ends,remove it and manipulate link to feel if wire inside is broken/burnt thru. They rarely fail from age alone,usually an electrical fault that melts them.
They are getting hard to find,some replace them with plug in type fuses like what are found in a 2nd gen RX7.
They plug in to male terminals in fuse link connector like they were meant for it,direct swap. A 40 amp fuse will cover main fuse link and a pair of 20 amps will cover the other two links.

I would begin by doing previous checks I outlined in last post to see which direction you need to go.
Next turn on everything in car and see what doesn’t work that did previously...headlights/dash and taillights. Heater fan,wipers,radio. All warning lamps at bottom of cluster should be illuminated with key on. Seat belt light is grounded thru a timer and will illuminate for @5 seconds and go out.
Something may no longer work. Check fuse links next,if nothing found there,go inside to fuse box inside car under dash. Ground lead on test light,turn on headlights and ignition switch to run position to energize all circuits in fuse box and probe back side of both sides of each fuse thru little test tab on front of each fuse on either side of amp rating.
If all fuse links are good and all fuses are good,leave everything turned on and ground test light lead to negative battery terminal and touch the test light to black/yellow wire on + primary terminal of each ignition coil, both should illuminate test light.
This verifies ignition switch is sending current to ignition system. Next you can remove each igniter connecter on distributor and check for voltage at each black/yellow wire. Test light should be bright like it was at coil + terminals.
If you have found nothing amiss at this point,touch the test lamp to each negative primary coil terminal. It should light as brightly as + side.
Leaving test light connected on negative side of coil and crank engine over and observe test light,it should wink or quickly flash dim/bright each time igniter tells coil to fire.

Di all these tests in order,by the time you get to this point,you will find something that shouldn’t be and further clues as to what problem is.
Post back results for further guidance.
Happy hunting.

thirdpedalnirvana said, "I noticed the cover that is in between the distribution side and the ignition side of the distributor was loose, but that didn't seem to be a problem."............so I bet the dist cap/rotor is damaged, and that's the problem.

When the alt belt went all the warning lights came on. Battery was strong enough to make it to the parts store, and back home.

At an earlier time, the ran around with a dead trailing igniter for the longest time. RPM would show, but when the engine was cold, it wouldn't.

As an experienced owner, you should be able to recognize the fuel pump's humming when the starting key is on but the engine isn't. Once the engine suddenly stopped. The fuel pump suddenly failed.

You don’t bet on what automotive problems are unless you’re an experienced long time tech that recognizes early on pattern failures of specific vehicles and knows where and how to save time on diagnosis,but not always a sure bet.
Guessing or betting a particular part is bad is gambling- with your wallet.
You’ll note I mentioned I didn’t think that a misaligned cap was THE cause for engine shutdown/no start. It was something I suggested to easily check for after his mention of clicking sound when cranking engine after it no longer ran.
If it were the case,car would not run long in that condition.

Op mentions driving the car regularly recently and with that condition it wouldn’t run long enough to drive regularly and if engine was run to failure and that were to be the cause,very likely when he removed cap he would have seen shrapnel and dust fall out from rotor chewing on dist cap and terminals.

Check your battery cables...

My car ran strange, missing at high rpm, lots and lots of smoke on start up, really rough running when cold......but it still ran, then I discovered the inside of the dist chewed up. So maybe thirdpedalnirvana didn't look inside the dist and he just snapped it back in place like he said

Please read my description and not just my title.

I know what a bad battery connection look like. You don't get a working radio, working air, working dashboard lights when the battery becomes disconnected. Nor can you crank the car over with the starter and observe that the coils aren't sparking.

Any progress in finding your shutdown/no start issue?

My most recent problem with my car was bad wires. When working on that I was able to observe sparks from both the trailing coil and leading coil.

Correct. My fuel pump is functional.

Ok, so new info.

I checked the voltage at each coil terminal. I'm getting a consistent 11.9x volts at all 4 terminals. I also cranked the engine again with the coil wires off and they are still not generating a spark.

I don't have a timing light yet, so I visually inspected the fusible link block. there appear to be 3 fusible links, each spanning 2 terminals on a 6 terminal block. On the other side of the block, I only have 4 wires connected. Three on one side of the links, one on the other, I will attach a picture. I also found a single red wire with a spade connector just sitting loose below the fusible link terminal block. I followed the wire around to a relay just behind the strut tower on the driver's side. I will attach a picture of that too. I checked the voltage on the wire and it's 0.

Is that wire supposed to be plugged into the terminal block? what does that relay control?

https://cimg1.ibsrv.net/gimg/www.rx7...b5e8ab2a10.jpg
Fusible links from the top, with the disconnected red wire
https://cimg8.ibsrv.net/gimg/www.rx7...84303cb9e9.jpg
The odd hackjob that is the back of the fusible link terminal block
https://cimg5.ibsrv.net/gimg/www.rx7...8d2e77d210.jpg
The orange and brown relay that the red wire goes to.

That relay is aftermarket,has nothing to do with original ignition system. Trace wires from it and see where they go,are there any non factory switches anywhere on dash,did/does car have auxiliary lights on it.

Assuming you haven't recharged battery since car shut off and you have been doing some cranking on it. A good battery fully charged will test at 12.6-12.8 and those tests you did at the coils with good wiring would have shown 12+volts. Higher the voltage at the coils,the stronger the spark.
Am going to make a suggestion you discontinue trying to check for spark by disconnecting coil wires from coils and cranking engine looking for spark for two reasons. 1st,that test is meaningless,it's what is displayed at the plugs that's important. 2nd,if there were spark generated by cranking-without coil wires inserted in high tension towers on coils,the spark would come out of tower and run down to either coil terminal,in the process if done long enough,will create a carbon track on coil body that will continue to bleed spark voltage down the side of coil body under coil wire boot.. Only way to fix that is to replace coil. There is possibility of igniter damage from that much voltage dumped into ignition primary circuit.

So it appears you have voltage to both coils. Have you followed tests i suggested or skipping around and just checking some things. This would be the fastest road to frustration,and easiest way to start chasing your tail.
Suggest you start over by charging and testing battery voltage at battery terminals when fully charged and recording that,retest voltage at coils with key on. #s should reflect what i posted above. Continue testing from that point as i outlined and post back your results when you get to end of that list. By then you will have eliminated a lot of possibilities-and guessing and can be provided with the direction to go to proceed with diagnosis. If your problem was easy or simple,likely you would have found it and be driving the car now. Some problem(s) aren't simple to find/repair
You may think doing these things in order is tedious but it's how you conduct these tests and the results and #s generated that points which way to go next.
Also,a TEST light is different than a timing light,it's used to test circuits-often on a non running car. A timing light is used to check/adjust ignition timing on a running car.

I will leave you with this...this is an open forum,you will get responses from many people with different experiences and skill levels. The common denominator is they all wish to help YOU. Chastising a long time member like Kentetsu for suggesting you check your battery cables was unnecessary. He's been involved with RX7s for a long time and likely had some type of performance/driveability/no start problem that had to do with battery cables or wires coming from them and was just passing that memory on to you trying to be helpful. You have the option to consider or discard info in these posts-including mine. This is a nice site,arguably the best RX7 forums there are. Some really educated,knowledgable enthusiasts here that make a difference in the quality and content here. Every once in a while some snarkiness seeps in but majority of time people treat each other with civility. Maybe worst case scenario,some of these folks don't respond to your pleas for assistance. My 2c.

Did you test the resistance of your coils? 1.35 ohms (+-10%)

You could also hook up a test lamp to your igniter and take a wire running from + and touch it rapidly to see if it's working (Test both trailing and leading).

Also have you verified that ALL of your ignition fuses in the fuse box are good? Sometimes you get lucky.

EDIT: I forgot to say that 11.9 is low. Although if it happened while you were driving then you were probably above that. Still, your battery either needs a charge or you need a new battery.

@GSLSEforme your help is most appreciated. I want to start with that because I want to avoid the impression that I'm upset with the people helping me. Thank you for your time and for every post.

I will stop doing the coil spark test, but I wholeheartedly disagree that the test is meaningless. There could be spark at the coil and not at the plug, and it would mean a problem with my distributor, or wires. Because the coils are not sparking, I know that the ignition system is not grounding the coil when it's supposed to in order to cause a spark; it means i can rule out wires (new), plugs (new), and the upper part of the distributor that handles the... distributing.

You are correct that I have not put the battery on a charger. It still has plenty of cranking power and operates all in-car electronics including the blower motor just fine.

I have confirmed fuel (in the float bowls). I have not removed the spark plugs yet because they are a pain to get at since my car has AC and Power steering. I don't see the point of checking the spark at the plug end of the wires because the coils themselves are not generating a spark. If I saw them generating a spark, removing and inspecting the spark plugs would be the first thing I'd do. The rest of the tests you gave me involve a timing light, which I don't yet have access to.

If my understanding of vehicle ignition is correct, the battery charges the coil up whenever the ignition is on, hence a high volt reading on both terminals. Current flows from the battery through the coils and then through a high resistance wire back to ground. When the ignition system needs to make a spark, it shorts the battery 12V+ end of the coil to ground momentarily, which releases the energy stored magnetically in the coil primary into the coil secondary causing a high voltage pulse to exit the coil secondary, travel down the spark plug wire through the distributor, and eventually make it to the spark plug. If my understanding is correct, and considering the fact that the coils are NOT generating sparks, then my multimeter check of the coil terminals has ruled out the possibility that the coils aren't getting 12v from the battery. That must mean (please confirm my logic here) that either the coils are bad and somehow failed simultaneously, or the low-voltage part of the ignition control system is not shorting the coil when it should be. How would I check the proper functioning of the 12V side of the ignition system? how do I check for a defective coil? 12V power at the ignitors? It seems to me like it MUST be on that end, since the source of the high voltage (the coil) isn't making spark in the first place. Explain to me how it's possible to have no spark at the coil but have spark at the spark plug?

My car does not have any aftermarket lights or equipment, save for an aftermarket radio (functional) and an aftermarket fuel pump (functional). There is 1 switch on the dashboard, it's for the low-beams since the low-beam circuit burned out in the combo switch under a previous owner and they re-routed it to a rocker switch installed under the radio, because the previous owner didn't want to spend $250 on a new combination switch :icon_no2:. The headlight motors and high beams still go through the combo switch. I don't think this relay has anything to do with that modification because the headlights still work despite the disconnected wire. Are you 100% sure this relay is not stock for a 1985 GSL? My car is fully loaded except for the GSL-SE 13B engine. It also doesn't look like a new relay.

(EDIT: This paragraph is obsolete, read later comments)
You mentioned there are 3 fusible links. One for ignition, one for headlights, and one for "everything else". Can you tell me which is which? Is the lowest link the one for the ignition? Looking closely at picture #2 I posted, there looks like a minor hackjob going on. There is a metal tab apparently contacting 2 of the links , which is then attached to 2 wires. The bottom link has a battery-side wire but nothing connected on the other side. IF THE BOTTOM LINK IS THE IGNITION CIRCUIT, I think I should try connecting the red wire I found to that terminal, no?

OK so I just found page B-1 from the wiring diagram and I am more confused. It looks like the circuit goes from the 12V+ terminal on the battery, thru the fusible link, then to the ignition switch (so whatever fusible link handles ignition is working). From the ignition switch a wire goes directly to the coil. Everything I just described must be working on my car because the coils are powered. So fusible links are good.

I see where the tachometer gets its signal. The terminal on the trailing coil that goes to the igniter also goes to the tachometer. The fact that the tachometer gets no signal must mean that the trailing igniter is not functional.

From what I see here, the igniters get their power from the same place as the coil, directly from the ignition switch. So in theory, they should have 12V on one terminal at all times. According to the wiring diagram, the power wires are BW and the signal wires are YL and YG. So I should unplug the igniters and check if the black/white wire is providing 12V to the igniters.

Considering the hackjobs I'm finding on this car, I wouldn't be surprised if for some odd reason they re-routed the power to the igniters from the ignition switch to that "aftermarket" relay. Maybe out of concern that too much current was flowing through the ignition switch? Maybe the ignition switch burnt out? I'd think if you were going to relay anything you'd relay the coils, but I don't know.

I just spotted something else in the ignition circuit. The condenser. According to "the internet" the condenser makes it so that the spark going on in the distributor isn't as high a current as it is at the spark plug, thus increasing the life of the distributor contacts. Symptoms of a failing condenser are a weak spark or no spark from the coil. Where is the condenser located and how would I test it?

Ok quick update- i just tested the voltage at all 4 contacts going to the igniters (because I couldn't tell which contact is which without cutting the wire insulation). All 4 contacts read 11.9V, like the coils.

Of note, I checked my battery voltage and it's 12.2 volts. Would ordinary wire resistance explain the 0.3V drop between the battery terminal and the coil? Or is it indicative of some sort of problem? (perhaps a failing condenser)?

OK so I just found and unplugged the condenser. I tried cranking the engine. The tach needle doesn't jump or even wiggle, so that doesn't seem to be the problem.

It seems like the trailing igniter must have gone bad, since it should be sending a signal to the tach even if the coils aren't working right. Every time I've started or tried to start my RX-7 I've watched the tach needle wiggle around, it's kind of an endearing trait that modern cars don't have. Since it's not happening now, and the wire goes straight from the igniter to the tach, the igniter must be bad, but how could both igniters go bad at once? If you're only running on one set of plugs, doesn't it have to be the leading plug? I thought these engines can run with just leading ignition but no trailing ignition.

I also took off my dizzy cap and rotor, they look fine. I looked under the dust sheild and confirmed the magnetic star shaped thing is not loose, it does spin with the engine. I saw the magnetic pickups. How can I test them?

Your battery is low and needs to be recharged to even hope to get it started once you get spark. That .3 volt drop is concerning and may be causing you issues. The car will run on just the trailing and if you don't pay attention you won't notice it unless you hit a hill or accelerate quickly, then the loss of power is obvious.

Why are you here? There is enough info in this very thread to potentially fix your car. You don't want to take your plugs out? Dude, you working against yourself. Good luck. You're gonna need it.

There is NO mention of fuses here. You were driving and it died. That sounds like a fuse right off the bat. You can't just look at a part and say, "it's gotta be that". You will find yourself wasting money on parts that were working!

Imagine you buy coils and igniter and THEN you find a 15A fuse dead that is less than a dollar haha. To me that would be hilarious, not so much for you lol.

I am here to get help from this wonderful community of FB enthusiasts to understand my ignition system better. I am being bombarded by lots of information, some of which I know is demonstrably false.

For example, the claim that a battery with 12.2V when the charging system is not running is insufficient to start a car: 100% grade A Iowa bullshit. I'm sorry, but you're lucky to see much more than that from any lead-acid battery when the alternator isn't running.

I have no issue taking out my spark plugs. But I also have done enough diagnostic work to know that the problem isn't coming from my damn spark plugs. The coil is not being grounded by the igniter, which is the mechanism by which the coil makes spark.

I have checked my fusible links and they are fine. I can check my fusebox under my dash, but if you read my description all my dash lights work and the coils have 12V as do the igniters, so it's not a lack of 12V power at any of my ignition equipment.

@Rotary Alkymist is there a 15A fuse somewhere which would blow, but still give me 12V at the coils and to the ingiters, and not affect the operation of any other ignition-switch activated electronics?

@t_g_farrell I live in the mountains and I was commuting over a mountain the day my ignition failed. In order to ascend the hill I have to spend nearly the whole ascent at wide open throttle. I believe I would have been able to tell if there was a loss of power, which makes me think both trailing and leading plugs were functional. The failure occured while going down the other side of the hill, in gear, off throttle.