SpinningDorito

iTrader: (2)

Greetings RX7Club, as some of you may or may not know, I have a 93 FD that I am currently in the struggle of bringing back up to snuff. I'm starting this thread for a couple of reasons. Firstly, to document my progress, secondly to think out loud, and thirdly because I am punching above my weight class with some of this stuff, and if I am doing something totally stupid or I'm stuck I'd hope one of you would point it out and help me get back on track.

I got the car in early January, and I've been working on it like crazy since then. I finished up a total refresh of the interior about a month ago which I am planning on retroactively documenting here later (with some pictures), but suffice to say I'm fairly happy with what I got done there.

After getting all of that together, I promptly turned my attention to the engine bay. The good news is, it's pretty much what I expected. The bad news is, it's pretty much what I expected.

I pretty much have everything apart. I'm planning on tackling everything I can, so hopefully it will be a while before I have to dig in this deep again.

This is the current status, as I can currently remember (ignoring things I have done in the interior, and things that need to be done for the rear suspension)

Completed:
Total overhaul of the AC system + new compressor
Replaced all coolant lines with fresh rubber
Replaced stock AST with metal RP one.
Lots of little things (broken sensors, missing/rusted/broken bolts the PO left me, etc)
Replaced broken washer fluid tank
Replaced thermostat with new OEM model

In progress:
Replacing the stock radiator with a fluidyine model, upgrading the fans to RX8 series 2
Replacing shot sway mounts, bushings, endlinks (waiting for AWR mounts to show up)
Replace water pump with re-medy model, replace gasket, replace water pump assembly to engine gasket (had to take it off because the bolt shared with the alternator snapped)
Replace EZ-baked vacuum lines with good silicone lines
Replace stock down pipe with something that doesn't suck (will replace midpipe with RP high flow cat + RB dual tip exhaust since the stock muffler is shot)
Replace single oil cooler with OEM dual cooler setup


To-do:
Replace broken thermosensor with FC thermosensor
Replace broken fuel temp sensor
Send fuel injectors out to get tested/refreshed
Replace FPD
Replace rubber fuel lines
Fix literally all the suspension things
Install improved solenoid rack near the ABS on the passenger's side
Address known engine codes (23, 28, 30, 38)

Will probably do:
Replace brittle OMP lines, maybe injectors


Finally got the rats nest/solenoid rack off today, but that just raised some more questions. One of my engine codes is 28 (solenoid for the EGR no good), but my car doesn't appear to have an EGR (was expecting this), or even have the electrical connector for one(was not expecting this).

Personally, I'm fine without it, but I was hoping to put a resistor on the harness to prevent the CEL from coming on. Really scratching my head that the harness plug doesn't appear to be present. Were there any 93's shipped without EGR?? The hard lines seem to be present, but not connected to anything.

All the other solenoids appear to be present, but the engine codes indicate some of them are broken. No biggy, I'll get those in with the new silicone lines/check valves etc.

All that's left is for me to figure this out, and get access to the fuel rails so I can start refreshing everything. I figure if I can get through all this, this car is downhill from here.

I guess the second thing I am researching/looking for input on is if I am missing any valves/etc that I should take a look at while I have everything disassembled. I'd like to get ahead of anything that might have one to many heat cycles on it.

The car drove alright (which is nothing short of a miracle based on all its worn out stuff), with the exception that it fell flat approaching the redline. I wish I had done more diagnostics on the system before I started getting into it, but I've just been proceeding with the mantra that all the wear parts are broken/close to failing, so I'm fairly confident I'll catch whatever issues may have been present in the process.

Attaching some pictures of my solenoid harness/rack. Maybe someone else can make sense of my ghost EGR solenoid (I think its 'D' in the diagram).

SpinningDorito

iTrader: (2)

Had a light bulb go off in my head about this EGR thing, and it goes back to this kind of odd wiring repair I had to make a while ago.




Essentially at the beginning of my journey, I found this yellow wire that spliced into the harness right by the passenger firewall (and by spliced, I just mean twisted together by hand). It ran down to the small sensor next to the oil pressure sender. The oil temp sensor is what I believe it is. There was also a poor splice to the sensor that I had to repair.

Now, I'm not a RX7 expert by any measure, but that one thing always seemed weird to me. Why spliced at both ends? I chalked it up to just something weird a previous owner did, and moved on with life.

Now, with the seemingly missing EGR plug, I was reminded of a thread I read when I was thinking about installing a less heat-soaked harness. I was looking into Auto transmission and JDM harnesses because I have seen some for sale in good shape for cheap.

Re-reading the thread (https://www.rx7club.com/3rd-generati...arness-706857/), I realized what sounded familiar:

I think there was another thread that actually called it out as the yellow wire, and obviously a JDM harness wouldn't have the EGR solenoid connector, as that system doesn't exist on JDM 7s.

This also raises other interesting questions about some of the CEL codes, as this thread (https://www.rx7club.com/3rd-generati...s-spec-868289/) calls out a lot of the weird stuff that will happen with a JDM harness if you don't re-pin it to the ECU correctly.

What caught my eye was the reference to the fuel thermosensor error code, which I am seeing on my car. Looks like the pins for the cooling fans are in a different spot between the US and JP connectors too, which might explain why my fans only seemed to come on reliably when the AC was turned on (thermo sensor is also bad).

So now I'm questioning if I have a JDM harness that perhaps isn't installed completely correctly, which makes me kind of wonder if my engine might be JDM too since all the vac lines were missing for EGR on the rats nest. There is no telling how far this conspiracy goes.

Do any gurus know a good way to identify the harness and engine type, not knowing the history of the car? Am I reading too much into a missing plug and a bad wire splice?

In the meantime, I'm going to keep reading up, and see what I can figure out. Seems like I might need to take a closer look at the ECU plugs, and the engine electrical in general.

SpinningDorito

iTrader: (2)

Found this vacuum diagram for the early JDM models. Looks pretty identical to what I am seeing on my rat's nest

Something else supporting the JDM theory, is that this hose/nipple specified in the USDM spec is not present (the top yellow one going into the lower intake). The plot thickens.

SpinningDorito

iTrader: (2)

Did some more looking around today. The car definitely has the JDM harness in it. The old JDM connector is still there, with my fuel thermosensor wire hanging out in it.

So, between that and the non-existant EGR solenoid connection, I think that explains my 23 and 28 engine codes. The only other code I have/had was 38, and I don't see any reason that would be related to the harness (at least not yet).

Found the N3A1 stamp hidden on my engine block, but the N3A7 stamp on the lower intake. All in all, the harness install and EGR removal seem more thought out than a lot of the other things I have seen on this car, which is a pleasant surprise.

I'm going to repin the thermosensor wire to the X14 connector as documented on a few places on this forum. Unfortunately that wire pulled out of the pin when I depinned it from the JDM X-05, but I'm sure I can track one of the pins down.

Also noticed the fan recall harness black connector isn't being used right now. I'm doubtful there is an easy way to get it working with my harness, but from what I have read its not a big deal once you move away from the factory downpipe.

Seems like I'm stuck with the EGR engine light though (at least until I get a PFC in) which is a little annoying. Can't wire a relay/resistor if there isn't' anywhere to wire it to.

SpinningDorito

iTrader: (2)

Exhaust connections under the car were pretty crusty, so since I'm replacing the entire system anyways, I just dropped the whole system at once, which was fun.

Luckily the downpipe nuts came out fairly easy, so I can't complain. I'll be replacing the stock exhaust with a RB dual tip + Bonez highflow cat + megan racing stainless downpipe, with a DEI exhaust wrap. Will probably need to order some new exhaust hangars, since the rubber on mine were a little questionable looking. It also looked like I might have been missing one around the cat area, so I'll have to go back under and double check that too.

I also have some much nicer heat shields to replace mine with before I put the new exhaust in.

rx7fitz

iTrader: (1)

Good stuff man! keep it up, I'm interested in seeing it come together.

SpinningDorito

iTrader: (2)

Nothing too exciting this week. I have most of the hoses/lines replaced finally. I went with a blue silicone kit (good, thick walls on the hoses) for the vacuum lines/washer lines, OEM replacements for all of the cooling lines (the turbo coolant hoses were pretty sketch, not sure how many miles those had left), and I'm waiting for OEM replacements to show up for the air intake hoses, since a lot of mine are pretty rough.

I'll be replacing my brittle omp lines with some stainless ones from RP, plus new oil injectors too. Waiting for those in the mail.

Replaced the firewall fuel lines with Gates Barricade 5/16 line. Seemed like a good fit, but we'll see when I can prime the pump and check for leaks. I was able to transfer the rubber foam protectors from the stock lines, which was cool.

Found a replacement pin for my thermosensor line, so I repinned that wire to the X14 connector. That should clear up that fault code once I have everything put back together. I was able to repin my pressure cutoff harness to accept the 2 pin connector that the newer santech replacement sensors use too.

Most importantly, I finally removed my sway bar mounts. I didn't get a chance to put the replacement AWR mounts on (I need to replace my end links too first) but it felt good to get these things off finally.

I know that the cooling line replacement "kit" is pretty well documented, but I didn't see a list for all the air hoses any where. These are the air hoses that are still available from Mazda that I ordered, I'll report later if anything important ends up missing. Only one hose was NLA, it was the one that comes out from the side of the air box. Fortunately mine is still in decent shape. Should run about the same as the coolant lines do.

n3a1-13-765
N3a1-13-767
n3a1-13-766
n3a2-13-760
N3A1-20-751
N3A3-13-750A

These are the air tubes that run to the cat, under the car
n3a1-20-850a
N3A1-13-815

SpinningDorito

iTrader: (2)

Thanks! I know a lot of the builds on here are more interesting, but I think its good to try to document some of the gotchas with putting the stock stuff back together.