Full Frontal Lobotomy

I encountered a strange issue when driving around my SW20. In the morning it started just fine, but after a second I heard it grind and the starter was spinning up, like the solenoid just extended. This has happened a few times so I didn't worry about it. It retracted. I got about 20 feet down the road and it happened again, it was just stuck out. So I turned around to switch cars. As soon as I parked it, shut it off, pulled the key, the starter is just cranked away. I had to pop the hood and pull the battery terminal. So I needed to dive in to some wiring. This is a pretty simple circuit, not much can go wrong. I checked the relay, the wires going to the starter, and those did not present any issues. Weird. Traced the body harness, those were all fine as well. Weirder still. Well, that only leaves one portion that I hadn’t checked.
The dash harness.
But, this gave me an opportunity to fix/change a lot of things that I didn’t like or were “fixed” enough to ignore. Biggest of which, the classic lifting SW20 dash. Lots of poorly done wire repairs, mostly from previous owners, but also some bad OEM wiring from Toyota. More on that later. I could also use this opportunity to lobotomize that which is vestigial, i.e. any wire that is not currently used or connected to anything.
I’ve been hanging around with Alex Wilhelm too much.

First thing first, get the dash out. I have heard from many people that this is incredibly difficult, and even heard from some shops that this is a 12 hour job. So I was always scared of doing this.

Frankly, I don’t know why everyone makes a big deal out of this. It was easy. Maybe 45 minutes or an hour of work?
Once that was out, first things first I wanted to install the oversized vent covers to fix my lifting dash. This way the leather could “settle” back down slowly, and I could tighten it a little more each day. My friend Devin made a few sets of these and sent me one.

Nothing significant to report here, install was simple and went as expected. It’s nice to see a flat dash again. If I were to have made these I’d radius or chamfer one side of the plate, to allow it to recess slightly into the dash. I don’t have a router, I’m not about to hand file this, plus these are powder-coated so I’d either have to re-coat them or be okay with an exposed silver edge. I decided I’d leave it be.

In terms of setting out what I had actually intended to do, after the scope creep at least, was to just de-loom everything. This took the better part of an evening. Oh, what a mess I got myself into.

The actual delooming of everything wasn’t hard, the hard part was carefully removing all of the plastic brackets and guides without breaking anything. More on that later. After this, I had a long and arduous task of comparing both sides of every connector, and any pin that existed on one side but not the other got pulled. Any pin I removed, I’d follow it back to the next connector, remove the pin on that end, then repeat. This was tedious but not difficult. The difficult thing was just snaking all of the wires out after depinning. I also took this time to remove now superfluous bracketry and components. Anything not used is gone.

Here’s what I had removed after “Phase 1”. All of the speaker wire (I removed my sound system 4 years ago), amps, airbag system, seatbelt warning relay. Some of this stuff I wouldn’t remove if it all worked. Personally, I’m not going to try and get an entire airbag system working. This is not advice. Stuff like the seatbelt warning relay I was okay with removing because, well, I can tell without a light if I don’t have my seatbelt on. I never drive without one, feels weird, so this box was doing essentially nothing. One thing that really surprised me in this is just how many twisted pairs run through the dash. Speakers makes sense, so really there shouldn’t be more than maybe four pairs. There were a lot more.

Here is where I found the starter issue mentioned at the beginning of this post: All of the wires going from the ignition switch to the dash harness had broken sheathing. It was really easy for the wires to make contact with each other. Honestly, that makes me wonder if my car has ever cranked over in its sleep before. Huh, that’s a weird fire hazard.

I’ll keep whittling away at this, but there are many details I will omit or gloss over. Just know that there was a lot more to this than the above.

A previous blog post I coined the term the “Hot-Rodder’s Fallacy”, the “while I’m in there” mindset. So I’ll indulge on that here.

Living in Arizona, I still do have a functional AC system. Also from living here, the whole thing is dusty. Personally, I don’t enjoy getting hit in the face with sand on occasion. I don’t like sand. Beyond just sand, the entirety of the system is over 30 years old at this point, has been here its whole life, and the Phoenix heat has not been nice to the foam and insulation. It’s not very foamy anymore.

That’s disgusting. So all of that was occasionally falling off, flying through the ducting, and hitting me in the face. Lovely. This was nowhere near the grossest part.

Yup, there was a nice wet sticky moldy(?) mass of sticks and leaves near the bottom of the evaporator. Always wondered why my car smelled like that. Needless to say, it was time to take the entire ductwork apart to clean it. This was pretty easy but tedious. Split the duct if possible, spray it with dish soap, and literally rinse and repeat. Luckily I have a big kitchen sink so I could do this in a contained manner. I also took this time to delete my nonfunctional heater circuit. If you look closely at the heater core (2nd image above), you may be able to see that it is properly fucked. Clapped. Borked. I don’t care, I’ve never used a heater anyway. In the bin! A small 3D printed plate happily took its place. I was also able to remove the heater flap and associated linkage. Next time I drop the gas tank, if ever, I’ll be removing the heater core lines there too. The pile-o-removed-things grows ever bigger.

Actually, that’s about it on removal. There was a lot of detail I glossed over, but each car is specific on your use case, it doesn’t make sense for me to go in depth on every wire removed.

With some minor additions, this is how my parts pile ended. Even I had to call it on a few legs, I had to stop the scope creep somewhere. Notably, there is a big leg of the frunk harness that goes into the cab behind the dashboard. Four or five connectors, and I was only using one. So, instead of delooming the entire frunk harness and pulling those out, I ended up just pulling those wires through the grommet and leaving them in the frunk “for later”. Essentially it’ll sit there for a few years until I have to do something else.

I call this the “Taxicab leg”

The best thing about doing this has just been getting rid of bulk. It’s crazy how many vestigial wires exist in every chassis. It’s also nice to get rid of broken plastic clips and brackets, replacing with new where possible. However, in doing this I discovered something that I’ve never actually seen online before. I think anyone with an MR2 or any car this old has dealt with a broken electrical connector. There were a few on my car, but luckily enough there were enough connectors that I removed that I had every replacement connector already in the car. Dirty, but there. So, not really thinking twice, I threw them in my ultrasonic cleaner. Just dish soap, ultrasonics, and heat.

Ignore the shoe

Not only were my connectors completely clean, they were now completely supple. Seriously, it’s as if it got re-plasticized or something. I can squeeze on the release lever and not worry about it breaking. Honestly, I’m going to be doing this with every connector I remove from now on.
ANYWAY, back to reassembly.

Reassembly is the opposite of disassembly and whatnot. I started from the right side and moved to the left, that way I had the most slack possible near the chassis integration connectors. This proved to be largely unnecessary, I had WAY more than enough slack when it came time to plug everything in.

While I was here, I thought I’d finally do something I’d always wanted to, and I’ve heard some people talk of, but I’ve never seen anyone actually do. I ran the drive-by-wire harness through the dash harness. I just have it pop out where the brake switch goes, and plugs into the pedal right there. Very simple, but a lot cleaner on integration. Through all this I have a ton of open terminals at the body integration plugs, so I had plenty of options to hook into the same harness. Later, I will have to open up the body harness and run the rest of the wires inside of that.

While I had this apart, I decided to paint all of the orange rusty weathering steel parts under the dash. Every MR2 I’ve seen has been totally rusty here, and while I can’t see it while the dash is on, I was tired of getting orangey brown fingers any time I had to do anything behind the dash. At least on my car nothing actually grounds here, so this isn’t a problem to consider either. That steering shaft is still ugly. Maybe eventually I’ll do something about that…

Another “while I’m in there” that I fell for was finally switching to a turbo gauge cluster. Functionally no different, just gives me a more accurate higher redline and a higher speed. 2GRs in MR2s can easily exceed the speed on the NA cluster. Let us not talk about why I know that. Mike Reed mentioned to me at one point that he was considering switching to digital gauges, I said I’d grab his turbo cluster whenever he did that. The time finally came and happened to line up here. That was easy, both of our cars are USDM 1993s, so the cluster was plug-and-play besides swapping in the voltmeter from my NA cluster. Mike had some other gauge that didn’t work. Oil pressure maybe?

It’s still possible to maintain creature comforts while on a weight reduction plan. One thing I have not had in around 5 years on this car is cruise control. In theory this should be easy to get working on a 2GR ECU, just wire up the brake inputs and 2 wires for the CCS. But one problem, I have an aftermarket steering wheel and no provision to mount a cruise switch. Well, I don’t have windshield wipers so that gives me an idea.

Two quick 3D printed brackets allowed me to mount a 2013 Sienna cruise switch in place of the windshield wiper stalk. This does point more up than I’d prefer, but I needed this amount of room for my hand to turn the key. Kind of important in my opinion. Anyway, printed with ASA this is quite sturdy, though I will still consciously be careful here. Also, thanks Joseph Capra for the replacement combination switch assembly. If someone else is odd enough to do this same mod I’m happy to share the STLs in this case. I understand that most municipalities require functional windshield wipers. I’ll wire this up later but now it’s at least there.

At one point talking to Alex I was inspired to take this a few steps further. There wasn’t that much mass that I lost in wiring. There’s always room for more. Step 1 was to switch to a newer planetary gear starter. I believe this saves somewhere in the neighborhood of 4lb, but I may be misremembering. I don’t actually have a picture to go with this so you’ll have to take my word for it. Something that bothered me slightly about this, the stock MR2 starter wire is not very flexible and the newer starters move the lug to a different spot. It will work, but its less than ideal. Alex switched to a more flexible 4awg wire, and I followed suit.

Believe it or not 4awg is actually rated for all of the load here. This saves a bit over 2lb. I get to (slightly) shorten the wire and give it a lot more flexibility, making the whole setup around the newer starter a lot better.
But why stop there?

If you give a car a tiny battery cable, it will want a tiny battery to go with it.
Again following Alex here, I switched to a Noco NLP14 LiFePo4 battery. This thing has no problems starting my car, and only weighs around 2lb. The stock battery weighs almost 37! There is a part of me that wants to move this in the cabin and shorten wires even more, but I worry about voltage drop to some sections of the car. I made a bracket out of some random steel strip I found in my metal box. Weighs nothing, and that battery is going nowhere. Except wherever the car goes I guess. It’s going nowhere relatively.

So, where am I at?
I saved everything I removed in a bucket for easy weighing when done. I did not save tape or loom because I’d be reinstalling a bunch of that anyway. So, rough numbers regardless. This is counting every wire removed from my dash and door harnesses, the heater core, and the dampers I removed from the ducting.

So, 19.8lb, the bucket weighs a bit under 2, add the weight for the battery cable back in and we’re looking at about 15lb. Battery, 36.8, with the replacement at 2 and change, call it 34lb. Call it 50lb. Holy crap! Factor in the other weight reduction I’ve done recently such as the mirrors, this thing is getting lighter by the day. Some would even call all of this “low hanging fruit”.

Wonder how far I’ll go.