My Dad and I found a 79 and an 80 sitting side by side in a salvage yard. We brought them both home not knowing the stories behind either car. I originally posted the story in the non tech section but as it went along it became more of a technical thread. Since no one has responded to the last couple of posts I thought I would start again in the tech section where I may be able to get more help.
Here we go....We are currently trying to get the 79 running. We have fuel, compression sounds pretty good and we are working on spark. (thinking new wires will do the trick) All fluids look good and hoses look new. We have put new stuff in the dizzy (points, condensers, cap, & rotor button), new plugs, rebuilt the carb, new filters, etc...
Here's where the project stands...we have gotten a backfire or two out of her already, but for some strange reason here lately the starter stays engaged even with the key completely out. It does stop after 15-30 seconds, but it's obviously not functioning properly. We had the old starter tested and they said it tested good, but weak. We bought another one just in case. Didn't change what it was doing at all.
Someone suggested that it may not be grounded. There are 3 places on the starter solenoid for wires, right? One of them has the ground from the starter bolted onto it as well. All seems good. One of the wires was not hooked up when we originally tried to start it. (the bolted on one on the right where the starter ground bolts, as well). I traced out the wires and figured out that the fusible link that was there was fried and ran a straight wire for now.
Now the starter occasionally makes this horrid noise and still continues to run after shut off. Thought it may be a faulty ignition switch. Changed it, no change.
After much searching through over 500 threads, the Haynes, Chilton's, and wiring diagram manuals I came to the conclusion that it may be the ignition relay.
Go ahead, I know you already are laughing because you know that I can't get another one from Mazda or a parts house. So, my questions are:
Can I somehow check to see if the relay is indeed my problem?
Is there something else I can check?
I'm at a loss here.... Even the dealership mechanics couldn't (or wouldn't) help me. Thank you all in advance....Kymber

 

Do not bypass a fuseable link for one. It's designed at a amperage breaking point. Bypassing it opens your system up to all kinds of major fry or even a fire.

A fried link is a good sign that you suffered a major ground fault. Might need to replace the cables too.

 

Trial and error hasn't worked so you'll have to get facts and analyze them. For electrical problems that means you need a voltmeter. Fortunately, you can get a good-enough voltmeter from Radio Shack for about $15 or from harborfreight for about $7. Lacking a voltmeter you can use a 12v auto bulb with 3 feet of zip wire soldered onto the contacts and alligator clips at the ends.

When you find a bad part and the dealer has no replacement you can probably get it at a Pick 'n Pull near you, or you can post a Want To Buy (WTB) in the classified section here at the rx7club BBS. Probably, someone near you has one.

 

China mart has a tester too. It's not uncommon for the battery cables to fry.

 

Don't bypass fuseable links, you may allow excess current to damage something more important than the fuseable link. You can get replacement material in a bubble pack at any autostore.

 

Okay...at the time I put the wire I was not aware there was a fusible link there originally. I looked under the 1980 and saw one there, so I assume there should be one on the 79. There is not one on my 83 nor my 82. This still does not answer my question about checking the system. I do not have a voltmeter, but do plan to pick one up. I do have a test light. Just don't know what to check or how to check the relays...

As far as battery cables go...All systems work...the starter just keeps spinning after I turn off the key. It did this before I hooked up the wire where the fusible link material was and it continued after. My question still is not answered.

Oh, and Vashner...I'm a girl, but I'm not stupid...thank you anyway, but you told me something I already know and still did not answer my question.

As far as a Pick-N-Pull goes...the closest one is in Tallahassee and that's over an hour away. I guess I could call ahead of time and make sure before I go....
I don't mean to sound frustrated...I just am.

 

When you say that the starter keeps spinning, is the motor still running? Is the starter engaged with the motor or is it spinning freely? Does it always do this?

 

The ground should come from the battery and then be attached using the bolt that runs in from the front of the engine. The starter is self grounded at the case.

You can test the starter by connecting a wire from the small spade on the starter throught a manual switch to a power source, turn the key on, then press the button, if it still does the odd part you will know it is in the starter. if not you will know it is in the switch part.

 

Sounds to me like your problem is NOT that the starter won't spin, but that it keeps spinning even when you release the key. Perhaps even when you turn the ignition off and remove the key. Am I right?

There are only two reasons that the starter will continue to spin:

1-voltage is still being applied to the tickler coil on the solenoid (the small spade lug, about 3mm across, 3mm long, and 1/2mm thick, that is on top of the solenoid), or

2-the starter pinion gear is still engaged with the flywheel ring gear, possibly jammed.

 

Well it must be getting voltage to the solenoid to keep spinning. Is there an exterior starter relay on the SA's? That sounds like a likey culprit since youve replaced the ign switch. That or the starter solenoid is sticking after the key is released. Do the SA's have a cold start system? Maybe you have it wired up wrong and the cold start is powereing the starter?

 

Negative battery cable goes from negative terminal to a bolt on the shock tower, to a bolt on the back of the engine near where it meets the tranny.

Positive bolt goes from positive cable directly to the bolt on the starter, with a small branch going off to the fusible link box.

Since the starter is spinning up, it sounds like these are already hooked up properly but I thought it'd be good to reiterate.

The starter itself has two wires. One is the biggass positive from the battery, which goes to one of the two bolts on the starter solenoid (the one that *DOESN'T* have the wire going into the body of the starter itself). The other is a wire which connects to the spade connector on the solenoid.


The idea is that the positive is always going to that one bolt. It gets ground through being bolted into the tranny which is a giant metal hunk. When you turn the ignition, positive charge comes down that small yellow-blue wire into the spade connector. That tells the starter to open the floodgates and let all the positive from the battery's positive cable to come out of the solenoid through the other bolt and go into the main body of the starter.



So now that we have the wiring and theory out of the way, what can go wrong? Well as bliffle said, if something is causing that little spade connector to continue getting signal after you let go of the key, that will keep the starter spinning, or if the teeth of the starter get stuck in the flywheel the starter will continue to spin until the engine loses the momentum the starter put into it.

But I had something similar happen when I had the Positive cable from the battery hooked to the wrong post on the solenoid (the one with the wire going to the starter). Why it didn't crank all the time is anyone's guess, but I'd check that.

Past that, grab the heynes and look in the troubleshooting section. I recall them talking about ways to test the ignition cylinder itself. Something about a "big white wire with red stripe" or something like that. That will let you test if the ignition cylinder is bad or sticking.

Keep pluggin' away at it, you'll get it eventually.

Jon

 

Okay...Negative cable is correct....positive cable is correct....post with wire going into the body of the starter itself has a wire with a fusible link on the end bolted to the solenoid...other end goes into the harness which seems to end up at the ignition relay...small spade has a wire going into the harness at the same point as the other wire. It also seems to go to the relay, but I could be wrong...
I tested the ignition switch...when I turn the key to start the proper wires are getting power (per the diagram in Haynes). When I release the key, and even take it out, the black wire that goes to the ignition relay is still getting power, although it isn't supposed to out of the start position....the test light goes dim, but it's still getting power.
This is what is leading me to believe the relay is bad. It's still letting power get through after it should be shutting it off. It does eventually stop so the stuck in the flywheel theory sounds plausible. How do I fix that? Shim it? hmmm...that could also explain the noise it makes from time to time...like metal grinding. I'll check into that.
Can you purchase shims or is there a way to fashion them? I never thought of that...
Thank you guys...finally some useful information...btw...I picked up connectors and fusible link wire yesterday (thank you for that tip, Bliffle). I'll replace that before we do anymore testing.
RX7Carl...the 79 does have the cold start assist...I double checked all the wiring and the cold start assist is all good. At least I can rule that one out! Thanks!
Kymber

 

It sounds like the motor is still running....I was under there day before yesterday testing the wires and such when it was doing that....all the wires were still getting power after the key was shut off.

 

Kim,

I don't have time right now, but I will say there is no relay that is involved. There is the key, a fusible link, and the starter/solenoid. Either there is a problem in the ignition switch (I know you changed it), a problem in the wiring, or a problem in the starter/solenoid. I'll give you a run down of how everything should be wired and what to test once I get some extra time.

Good luck.

Kent

 

Awesome! That would be great. I just followed the wiring diagram (which I'm still learning how to read) and that's where it led me. It seemed that the wires from the ignition go into, and out of that relay and they also meet up with the wires from the starter. I unplugged the relay and got nothing, replugged it and got power, that's led me to believe that the relay was in the circuit.
I can't wait to find out what to test...I finally got a voltmeter..Yeah! LOL

 

see if you can get the part number from the relay and there may be another one of the same kind elsewhere in the car that you can swap out for to confirm or eliminate the ignition relay if not see if you can slave in a high amperage switch to bypass it and switch it yourself. If that fixes it go with the relay if not its a mechanical problem such as the binding in the flywheel as metioned earlier or the solenoid taking a crap. My starter was sticking once in my 1st gen and I just took it apart and lubed everything good and haven't had any problems since

 

By pass the switch entirelly so you will know which way to trouble shoot.


It is as easy as jumping power from the + on the starter to the spade. Make sure it is out of gear, and use a button if you dont want to do it from under the car.

 

Thanks ya'll! Now I have some things to check out this afternoon...Update ya'll tomorrow!

 

I'm going to speculate that the PO had some kind of problem with the electrical circuits, couldn't fix it, tried some hacks without understanding electricity or circuits, got frustrated, cursed the car and sent it to the wreckers. Perhaps even now he's going around telling people how bad RX-7s are.

But his stupidity is your gain. that's the reason you could get a good car for very little money. Now you have an opportunity to use your brain to make it real.

Don't despair. I have several degrees in EE, have worked on every kind of car for 50 years, and I've been fooled. More than once. Every time it was because I made an assumption and tried a shortcut. There's nothing unknowable or mysterious about auto electronics, it all yields to simple analysis and well-designed experiment. Thoroughness. But trial and error will usually lead you astray, and may further screwup the situation.

One of the most common problems with auto electrics is a simple lifted ground, usually corrosion at the battery terminals or where the negative attaches to the chassis. Which is why the first thing I do is clean the posts. The second is to touch the voltmeter to the center of the negative post and the engine and check for zero volts, as it should be. Then touch between the center of the negative post and the chassis and check for zero volts.

The experiment that hades12 suggested is very good, because you can determine if the starter both engages and disengages properly upon applying and removing the solenoid tickler voltage. Perhaps it will plainly point to the starter and solenoid as the problem. Perhaps the experiment will exculpate them. If the starter/solenoid is kaput you have a simple solution: replace them (usually you can't get just a solenoid and they are difficult to disassemble) with a rebuilt unit from the autostore or rockauto.com for $100, or go to the PnP and pull one for about $20. I prefer a used starter to a rebuilt: they've proven more reliable.

To perform hades12 experiment it's nice to have a Remote Starter Control so you aren't under the car when you try it, and you can either get a $5 unit at the autostore or just use a pair of alligator tipped wires, one attached to the spade lug at the top of the solenoid and the other attached to the positive terminal (either on the solenoid or even at the battery) then when you touch them together the starter should rev over satisfactorily, and when you separate them the starter should stop.

One of the things that happens to solenoids (we know from history) besides just plain burning out and ceasing to function, is that they stick. the high current causes arcing inside and results in a bunch of crud that can jam the armature. Usually they stick at the start of the stroke so they can't complete the circuit and all you hear is a click when you operate the ignition key. Then you get out your 12" socket extension, set one end on the starter from the topside, bang on it with a rightsized hammer a few times, and retry the key. Voila! Problem determined and temporarily solved.

But sometimes the solenoid sticks at the end of it's stroke and keeps the starter engaged with the engine even after the car starts. Hell of a thing! Lots of mechanical noise from reversing the pinion/ring gear forces. Plus, the starter turns into a generator and pours current back into the electrical circuits causing all kinds of (seemingly) weird results. Sometimes blows fuses, fuseable links, bulbs, reverses polarity of magnetic circuits (like, say, an innocent relay).

So do Hades12 experiment. Then report back here.

 

I did the spade to postitive test the other day and the starter spun and continued after I let go....The key wasn't even on at the time. It was freaky.
I mentioned earlier that the car did nothing with the relay unplugged...sorry...don't know what I was thinking. Ya'll were right. The relay has nothing to do with it. It did the same thing with the relay unplugged.
So now what? The car hasn't started since we've had it (just a couple of backfires). We are trying to get past this so that we can recheck the spark (it comes and goes...thinking bad wires)

I replaced the fusible link and it didn't blow, either. We are going to try and shim the starter tomorrow and I'm gonna clean the negative cable on both ends. I'm thinking it may be a little cruddy where it bolts to the engine.

Starter is a reman from Auto Zone. The original one was doing the same thing and tested good at the store, just weak, he said. We chose to replace it just in case. I have one on the 80, but since I don't have a key I have no idea if it works at all without taking it off and doing a bench test.

I saw a writeup somewhere on how to test the stuff inside the starter to see if it's working properly and I hope to check that out tomorrow just to rule out a faulty starter.

Bliffle, you said:
"But sometimes the solenoid sticks at the end of it's stroke and keeps the starter engaged with the engine even after the car starts. Hell of a thing! Lots of mechanical noise from reversing the pinion/ring gear forces. Plus, the starter turns into a generator and pours current back into the electrical circuits causing all kinds of (seemingly) weird results. Sometimes blows fuses, fuseable links, bulbs, reverses polarity of magnetic circuits (like, say, an innocent relay)."

This sounds more like what's going on...the mechanical noise stops after a couple seconds and then the motor stops turning altogether after a few more...
Could a shim possibly cure this??? We'll test the starter and see if it does the same thing off the car...I guess that would tell me something, at least.

I'm curious, though...since it's been determined that the ignition relay has nothing to do with this...then what IS it for?? I'm learning as I go and believe me...it's like being in college again! LOL

Thanks for the great info...tomorrow's another day!

 

I'm confused about this part....help me out! LOL
I have 3 wires coming from other places to my starter. The spade has a wire from the harness, the post with the wire from the starter body has a wire from the same harness and then, of course, the positive battery cable is on another post.
You state the starter has 2 wires...the positive, which is a given, but it almost sounds as though the spade should be connected to the other post...

I looked under the 80 and it's wired the same way as the 79, with 3 seperate wires going to the spade and 2 posts....Just wondering if there is another way to wire that may eliminate the problem...

 

The spadelug test exculpates the electrical system. The problem is at the starter.

Sounds like the autozone starter solenoid is sticking at the end of the stroke so that the pinion stays engaged with the ring gear. Just like the original starter. We all would hope not to get two bad starters in a row, but it's not impossible nor even unlikely (cf. the mathematician Poisson who studied such things, or any gambler who will tell you that luck comes in streaks and slumps) so you can't discount it. we all hope that the rebuilder would have tested the starter before selling it, but we don't know.

Since behaviour didn't change with the new starter we have to entertain the idea that the old one was OK. So have it tested again at another autostore. If it is merely 'weak' that probably means the nose bushing is worn so that the commutator gap suffers and power is reduced, and can be fixed with a 15cent oilite nose bushing and some new brushes.

Assuming that BOTH starters are OK, and that the spadelug test was performed properly, the only other reasons that the pinion could stick to the ring gear are that the ring gear is damaged to the extent it has a burr that will hangup the pinion, or the pinion and ring are misaligned, perhaps due to a bent bell housing where the starter mounts. Or perhaps due to a bad previous repair that left some damage behind.

Carefully examine the pinion gear on the old starter. Does it have any damage? That would indicate that the pinion and ring were bashing against each other and perhaps locking together.

You may have to examine the ring gear by removing the new starter and looking thru the mounting hole while someone slowly rotates the engine (altho any damage should look the same on all teeth).

I'm not aware of any 'shim' possibilities with starters, although I've replaced many of them, including 3 FB starters in one month.

 

Get another starter from Salvage or make them exchange that one.

The cables can rott inside too (you won't be able to see the rott under the cable cover).

 

Perhaps the PO ran over a road hazard that slammed the starter hard enough to bend something like the bell housing mount so that the ring and pinion are misaligned.

 

Wouldn't bell housing damage be clearly visible? I don't see any damage on the bellhousing, but the teeth on the new starter do have a little scoring. I will take a closer look at the bellhousing and flywheel when I take off the starter. Thanks for the idea. I had not even thought of that and it seems highly likely. If that's the case, though, how do I fix it??

The old starter is no longer here as I needed it for core.

Not a bad idea on having the new one tested at the store, although I bench tested it and it seems fine...

I wasn't shure about any shim, either. Never had one on any of my others...I shimmed it with a couple of washers to test the theory and it's doing the same thing. (Gonna remove those, by the way)

I have a little video of the sound it's making. I will post it as soon as I find my camera.