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Schizamm
Schizamm New Reader
3/13/18 3:07 p.m.

I'd also love some advice about what I can do or tinker with while working on getting it started. How can I clean up the electrics? I'd like to simplify the wiring, so maybe strip out a bunch of stuff I won't need or have in the car? Put in new fluids? Figure out if I have a limited slip dif (How do I do that by the way). Etc.

Schizamm
Schizamm New Reader
3/13/18 3:33 p.m.

Ok I tried something else, probably was stupid but I didn't l know what else to try. I took a piece of speaker wire left overs and touched the large wire to where the red wire connects to the starter and it engaged the starter. Didn't sound very good, was super clunky and grindy, but I heard it turn the motor over. So bad wiring? 

Agent98
Agent98 Reader
3/13/18 5:04 p.m.

Get the factory service manual if you can it saves lots of guessing.

Typical 12A problem is blown apex seals, that leads to no compression/hard starting.  Rather than rebuild that one, look for a Craigslist sale, may have to drive a bit to find a 12A. But the motor weighs about what a beer keg does is the good news. Other weird thing is if the cat goes bad and they are hella expensive  new--- and a universal one will result in a horrendously shrill and loud car due to the hotter exhaust temps coming out of the rotary engine. So, look for someone parting one out, get that cat. Junkyards usually won't sell you a cat..Still liking the 302 out of a grand marquis idea, or a chevy --granny's is one name. There's used kits out there too

https://www.ebay.com/itm/Grannys-speed-shop-CHEVY-V8-swap-kit-1979-1985-MAZDA-RX-7-/352277627792?hash=item5205620390

... either way -good project!

Hungary Bill
Hungary Bill UberDork
3/14/18 1:12 a.m.
Schizamm said:

Ok I tried something else, probably was stupid but I didn't l know what else to try. I took a piece of speaker wire left overs and touched the large wire to where the red wire connects to the starter and it engaged the starter. Didn't sound very good, was super clunky and grindy, but I heard it turn the motor over. So bad wiring? 

Either bad wiring or a bad ignition switch.

In your other post you said you had 8.3 volts at that red wire, even with the key turned off?  That's weird...

Potentially a good starter though!  (I say potentially because you mentioned the start was clunky and grindy...  Jury is still out on that one)

Did it just clunk and grind when it initially engaged or the whole time it was turning?

 

Hungary Bill
Hungary Bill UberDork
3/14/18 1:27 a.m.
Schizamm said:

I'd also love some advice about what I can do or tinker with while working on getting it started. How can I clean up the electrics? I'd like to simplify the wiring, so maybe strip out a bunch of stuff I won't need or have in the car? Put in new fluids? Figure out if I have a limited slip dif (How do I do that by the way). Etc.

I'm almost positive you don't have a limited slip.  to check, put the back end in the air and spin one tire.  If the other tire spins in the opposite direction then you have an open diff.  If the other tire spins in the same direction then you have a limited slip.

I might wait on stripping out too much wiring until you got the car running.  At least for now.  If you're hankering for something to do then I'd find out why the ignition key doesnt make the starter turn.  you can do this by following wires, checking for continuity in the wires with your meter, or checking for voltage at various spots along the way.  Wires work like pipes.  One of the pipes carrying electricity to your starter is broken.  Find that break and fix it.  We know there's voltage at the battery.  we know there isn't voltage at the little red starter wire.  Lets follow that wire back until something presents itself.

I'd hold of on new fluids (except gas,  you can pour new gas in) until we figure out where we stand with this engine.  I know you're on a tight budget so money for new fluids for an engine we might need to tear into might be better spent elsewhere.

I'm enjoying this thread!  I wish there was a forum like this when I had my first gen all those years ago :)

Keep up the good work man.

Schizamm
Schizamm New Reader
3/14/18 2:02 a.m.

In reply to Hungary Bill :

How can I check/change the ignition switch? 

Yes I had voltage with the key off. Really not sure why, but I have noticed everything seems to think the car is on as soon as the battery is connected i.e. gauge cluster lights up, volts going to starter red wire, and it clunks whenever I connect the battery. All symptoms of a bad ignition switch? Or maybe just hacked up wiring in the dash?

The starter was pretty loud and grinding when I connected the two. I can try and do it again and take a video. I did here it turn the motor over and get compression on the rear rotor though so that's good!

As far as the LSD, yeah I lifted the rear and spun the tire, the opposite spins the other way, so pretty sure it's an open diff.

I love working on the car! Just genuinely have no clue what to do. I go out all excited to work on it, look at this thread for advice on what to try, post about my findings, then have nothing else to try. Even trying to track down electrical like ignition switch or wiring to starter I'm clueless. But I am super grateful for everyone's advice and help!

Hungary Bill
Hungary Bill UberDork
3/14/18 2:46 a.m.

hmmmm.  I wonder if we can disconnect a plug on the back side of the ignition switch to eliminate it as a culprit to your "constantly powered" problem.  If you take the bottom plastic piece off of the steering column, can you see if there's a plug under there that goes to the ignition that you could disconnect?

With it disconnected AND the battery hooked up we can check for that voltage and the lights.  That would tell us which way to look (switch vs wires)

Good luck!

Schizamm
Schizamm New Reader
3/14/18 3:44 a.m.

In reply to Hungary Bill :

The entire interior is pretty much blown apart so I have access to all the wiring under the dash. What in this picture should I disconnect?

Hungary Bill
Hungary Bill UberDork
3/14/18 5:21 a.m.

 

Easy peasy.  Start where the wires end in the red circle and make note of how many wires there are and their colors.

Follow that bundle down until it gets to a connector and disconnect it.  Repeat until all the wires are disconnected.

Hook up a battery and check for lights/voltage at the red starter wire.

Cool thing to note, since you're in there:

See that screw that's between the red and green wires right next to my circle?  I'm not 100% positive, but that might be the only thing that's holding your actual ignition switch in.  If you remove it you can remove the white plastic "ignition switch"out of the whole ignition assembly. 

No real point to doing it other than "gee whiz, this is all this thing is?".  But once you see it removed you'll see how to start an old japanese car with a flat head screwdriver.  devil

Good luck!
 

Hungary Bill
Hungary Bill UberDork
3/14/18 5:24 a.m.

Also:  Sorry about my poor formatting skills.  That big space is there because my microsoft paint abilities are lacking today.

Hungary Bill
Hungary Bill UberDork
3/14/18 5:55 a.m.

lets see if this works...

 

Boom!

This should help us troubleshoot a bit.  Right away I can tell you that the red wire we've been talking about should have been black and yellow.

Schizamm
Schizamm New Reader
3/14/18 1:59 p.m.

In reply to Hungary Bill :

Hey Bill,

Thanks for your help! I'm at work and won't get a chance to check until late tonight, but that is great stuff! Definitely will be useful. I'll be sure to report what I find!

1SlowVW
1SlowVW New Reader
3/14/18 2:50 p.m.

Great stuff is going on here.

This thread has it all the exuberance of youth, knowledgeable posters with helpful advice, a Wankel, ms paint....it just keeps on giving.

Dead_Sled
Dead_Sled New Reader
3/14/18 3:05 p.m.

^ yea that.  I have nothing useful to add at this point, but I just wanted to chime in that the helpfulness shown in this thread is what makes GRM such a special place/group of people.  There's very few other forums where people are this helpful. 

No matter your skill level someone here will help you, and they'll do it without chastising you for not knowing how to chase wires.  Keep up the good work everyone yes

Schizamm
Schizamm New Reader
3/14/18 11:27 p.m.

I couldn't agree more with what 1SlowVW and Dead_Sled have to say. After lurking for a long time, I knew there wasn't anywhere else I wanted to post a build thread. The community is awesome!

Btw, huge (to me) update incoming!!

Schizamm
Schizamm New Reader
3/15/18 12:20 a.m.

I'll start by saying THANK YOU! to everyone who has chipped in with advice. You guys seriously are the only reason I felt comfortable picking up a project car because I knew GRM would help me figure it out.

A special thank you to Hungary Bill. MS Paint skillz, posted an extremely useful wiring diagram (that I saved btw), and helped me kind of guess what was going wrong.

Ok, update time. So I ran out the the 7 all giddy to try the things suggested. Hooked up my pillaged battery from my daily driver, and went to work. First, looked at the ignition switch, disconnected any plugs that seemed to contain wires coming from it, then jumped under the car to test the notorious red wire. Bill (hope I can call you that) realized that this wire should have been black and yellow. It was, three inches up and was spliced to the red one for I'm sure was at one time a great reason. When I had everything disconnected, I read 11.5v at the red wire. Wut. Color me confused. So I tried my best at following it up to where it led to under the dash, kind of ended up just guessing. But in following it up, I looked more seriously at what everything from the ignition switch was plugging into. It was all just looped uselessly. So the clips were plugged into clips off the switch, meaning they all led nowhere. You can see here what I mean, the bottom two white clips are both clips off the switch. So that wasn't good (I assumed what with my wealth of electrical knowledge and prowess). You can also kind of make out in the background the two brown clips that lead from under dash that were also looped.

So, I disconnected all of then, unplugged the brown connectors as well, and just matched up the ones that fit each other. Ended up like this, and now when I turned the switch (ended up using Bill's flat blade hot-wire trick, I'll explain in a minute) and could actually feel the start spot where you turn it and if you let go it turns back. That was new! Didn't do that before.

So after this, I jumped back under, reconnected the red wire, and then unscrewed the ignition switch to see what Bill meant about hot-wiring. Turns out it was a good thing I did, the small plastic flange that is supposed to turn the switch was mostly broken, so it wasn't engaging to ACTUALLY turn the switch to start. Would turn to on or accessory or whatever it is, but not start. Looked like this.

So anyway, stuck a screwdriver in where it needed to go, and tried to crank the engine. Nothing. Reconnected the battery (doh!) and guess what?! Starter engaged! It actually cranked the motor over. I could also hear the fuel pump turn on in on, so that was a welcome sound. Got REALLY excited at this point, and scrambled back to the list wvumtnbker gave about steps to get it started. Checked it had spark. Had to google how to do that since I didn't know you needed to ground the plug. Had spark. Let the fuel pump prime the carb a little, could see gas in the bowl (I think that's what it's called?), when I revd the cable I could see it spray gas. Called that fuel system a check. Last was to put all the plugs back in, google the spark wire order to make sure I put it back on right since I didn't remember how I took them off, (T1 T2, lowers were L1 L2 right?) and then the moment of truth.

Turned the key (screwdriver), if I turned it too far it would almost be to much and wouldn't turn on the starter?, turned it back a tad, and it was cranking. Gave it some gas, back fired out the carb, stopped then turned again, gave it more gas because that'll solve everything, and BAM! 

https://youtu.be/pWBbBfEEFf8

(skip to around 1:17 for the good stuff!)

Yeah. It ran. Sort of. Would love advice. What do you hear? Go crank it some more till it will idle? Apex seal blown and only running on one rotor? Don't ever crank it again my precious rotor housings could get damaged from apex seal pieces??? SO PUMPED! Thanks again to everyone!

Ryan

bbaker480
bbaker480 New Reader
3/15/18 7:45 a.m.

L =  Lower = Leading

T =  Top =  Trailing

It sounds like it's trying to start but just not quite there, I don't hear anything getting bashed around inside the housing so I doubt you have an issue with an apex seal.  You could always rent a compression tester and check it (and like everything else the rotary is a little different when doing a test) to at least verify that the two rotors are similar.  

wvumtnbkr
wvumtnbkr UltraDork
3/15/18 8:08 a.m.

Hold your finger over the spark plug hole while someone else cranks it.  Make sure you have the spark and fuel disabled when doing this.

 

You should be able to feel the compression and compare the 2 rotors.

Schizamm
Schizamm New Reader
3/15/18 11:44 a.m.

In reply to wvumtnbkr :

Should I take out both leading plugs and compare at the same time, or one at a time with the other plug still in?

bbaker480
bbaker480 New Reader
3/15/18 2:53 p.m.
Schizamm said:

In reply to wvumtnbkr :

Should I take out both leading plugs and compare at the same time, or one at a time with the other plug still in?

You'll do it one at a time, but you can take both leading plugs out and do them one right after the other.  

Agent98
Agent98 Reader
3/15/18 4:31 p.m.

 

Hold your finger over the spark plug hole while someone else cranks it.  Make sure you have the spark and fuel disabled when doing this.

 

You should be able to feel the compression and compare the 2 rotors.

 

You sure that's OK? I'm worrying if there is a shard of apex seal rotating in there good way to get a nasty nick.

Probably need to measure anyway...these are some low readings compared to a piston engine~85 psi no greater difference than 21 psi...at 250 rpm crank speed 

https://www.rx7club.com/1st-generation-specific-1979-1985-18/12a-rotary-compression-check-699874/

 

barefootskater
barefootskater Reader
3/15/18 4:54 p.m.

Life! Awesome. Keep up the enthusiasm. Rotary stuff is high on my list of cool/want. Keep the chips spinning.

Dirtydog
Dirtydog HalfDork
3/15/18 5:14 p.m.

Try this on for size.

1980 FSM

www.wright-here.net/cars/rx7/manuals.html

1983 wiring

 

Schizamm
Schizamm New Reader
3/15/18 8:06 p.m.

Well. Front rotor is dead. Compression checked and the front doesn't push any air at all. Rear, great compression! Seemed strong. But the front rotor definitely isn't healthy. Where too next? Pull the motor and rebuild? Find a cheap used one and swap? I'd love advice. Also pricing. Like I said at the beginning, I'm on a budget. If I can rebuild for cheaper, I'll go with that, if it's cheaper to swap a 12a back in, great. Full on swap to a cylinder (I know blasphemy right? And not even the cool kind like Blasp-Hemi) done cheap? I'm game for anything as long as I can afford it. Meaning peeps need to start buying ish and I need to save.

wvumtnbkr
wvumtnbkr UltraDork
3/15/18 10:29 p.m.

Well, it's free to pull the engine and take it apart (very methodically).  Start there and see what's wrong with it.

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