Emmett - 91 RT4WD Wagon
My 3 year quest for an untouched RT wagon finally came to fruition last year. After tons of dreaming, planning and parts searching, I've finally started digging into this baby. The story for how I acquired this gem is long and complicated. Suffice to say, as is with most wagon stories, it took years of searching, a lot of hassle and cost way more than most would expect. But after it all, I'm overjoyed to have it in my possession! I've been working on cars and builds for decades, but have always been a forum lurker and never really a poster. I finally feel like I have a project car worth writing about and documenting, so here goes my first build thread in ~20 years. I guess I better get on with it before forums are completely replaced by social media.
When I got it, it was a bone stock and completely unmodified 1991 blue RT4WD wagon with manual trans and 215K miles. One of the first things I did was get some new tires. These are the smallest all-terrain tires I could find. They just fit without rubbing. LT195/75R14 I think they look great!
So now on with the projects. Here's a list of what I currently have parts for.
- Power Windows
- Power Locks
- Power Mirrors
- Keyless Entry (with hatch release solenoid)
- Cruise Control
- Bluetooth Amp stealthily installed with OE tape deck
- 3 Stage Sound Dampening from SecondSkin Audio
- LED Bulbs for entire car
- New U-Joints
- Inno Roof Rack
- Custom made 6.5" Under-Seat Speakers
- Rockford Fosgate 6.5" 3-way Speakers for the front (will need to make adapters to mount)
- Fill diff mount bushings with 3M window weld to eliminate the clunk
And here's the list of things I have some or most parts for, or that are still in the planning stages. Obviously there's LOTS to figure out for this next section. I haven't even really started on the engine plans yet, but I do have the blue top H23 and clutch.
- H23A DOHC Vtech engine, new clutch and flywheel (installed to look like it came that way from the factory)
- Custom fabricated H2D adapter (I have a friend with a milling machine and lathe)
- Chipped P28 ECU
- Custom fabricated engine mounts
- Custom fabricated AC, power steering, and alternator brackets to align with H23 harmonic balancer
- Custom 2.5" exhaust made to look as stock as possible
- A trip to a good body shop to go over the car and fix all of the little dings and scratches and body color match paint all the black plastic (bumpers, door trim, handles, side skirts, etc.)
- Rebuild 4WD transmission (I have 2 spares and LOTS of extra parts to combine into the best one I can. I'm also trying to build a list of part numbers and sources for as many new parts as are still available)
- Figure out how to retrofit 86-87 RT4WD wagon push-button transfer case actuator and install 4WD button ( I have an 87 trans with linkages and the button but it's missing the actual actuator)
- New Fluid for Viscous Coupler
- New Diff Fluid
- Rear Disk Conversion (just in the dreaming stage at this point)
- Fix the AC and convert to R134 (haven't started diagnosing the issue yet. compressor clutch engages but there's no freon in the system)
- Go through the suspension and check all ball joints, tie rod ends, etc. Nothing feels loose and the car drives great, I just want to check everything.
- Flush break fluid
- Flush power steering fluid
Here's some of the progress I've made over the past week or so. I decided to start on the radio first because I originally wanted to do a "before and after" with the sound dampening. I ended up changing my mind after the OE tape deck I had turned out to be junk and I am waiting on another to ship to me that won't be here until next Wednesday. I didn't want to sit around twiddling my thumbs just so I could do a before and after, so I decided to continue on with the rest of the project while I wait.
First I had to remove this Sony radio adapter and replace it with the stock radio plug. This ended up being unnecessary later on since I took the entire dash out and have a replacement dash harness with uncut radio wires. But the process was still worth while for testing the first radio and to get the ball rolling on the search for a working unit.
Then I needed to make a bracket and mount the Kenwood Bluetooth amp in a tucked away location. It just barely fits above the AC box.
Then on to the control box for the amp. This is the main reason I got this product. With some EXTREMELY delicate dremeling, the control box just fits inside the ash tray. I used some white plastic to make a piece of trim to fill in the gaps and finish off the look. It's super glued in, so here's hoping that it never breaks, but if it does, I have debonder and can dissolve the superglue to remove the back and replace the unit if I need to. I love how it turned out!
It was at this point that I discovered that OE stereo I got was no good. At least I got everything installed so that I know what the wire lengths will be for integrating into the dash harness. And that leads me to my next couple of steps which was figuring out where the other new buttons were going to go so that I could add their respective connectors to the wire harness in the correct locations. The only new button I was going to put in a non-factory location was the main cruise switch. It is supposed to go on the left side of the gauge cluster in a 3-slot mounting bezel along with the dimmer and rear defrost button, but I don't like that location and it would make the wiring more difficult since those are both on the dash harness rather than the body harness. So, I decided to put it in the slot next to the power mirror switch.
Some more very careful dremeling and super-gluing and a coat of flat black and it looks great!
When I collected all the parts for this project, I wasn't very diligent at making a detailed shopping list and the availability of good donor cars wasn't particularly good. I had to drive a few hours to find a blue interior car and I wasn't quite sure at the time about exactly what extent I was going to be jumping into this project, so i didn't pull the complete harness from that first car. BIG MISTAKE. Once I started getting into this, I realized that merging the relevant parts of the sedan harness with my wagon harness was going to be WAY easier than splicing in dozens of wires. But by that point there were no longer any 90-91 5-speed sedans with all the power accessories in my area. The closest was at a pick-n-pull 3.5 hours away and there was no way of knowing if it still had an uncut harness with all the connectors I needed. So, I decided to check out what I could find locally.
The best I could do was an 88 sedan and an 88 SI. The sedan didn't have cruise control but the SI did and the 88's didn't have auto seat belts or the same dash dimmer circuit that the 90-91's have. That meant that the door connectors were different since there wasn't a door latch switch to trigger the auto seat belts and the cruise control gauge light didn't have the dimming circuit on the back of the cluster (I forgot to get that connector from the frst car I pulled the cluster from). All of these different combinations of options started me down a path where I eventually found a solution that I was happy with. I could use the 88 body harness and only have to splice in the cruise control stuff and I could get the cluster plug from the SI (even though it was missing the dimmer circuit wires). This would mean that there would be nothing to trigger my auto seat belts since the 88 door connector is a different size to accommodate a different number of pins.
This is where it dawned on me to do some exploring and see if I could modify the lap belt switch to function the same way at the door switch. This would not only let me eliminate the driver's side door switch and therefore use the 88 body harness, but also it would change my auto seat belts to trigger from me putting on my lap blet rather than from closing/opening the door. Once I started pulling things apart, it was almost like Honda was begging me to do it.
To make the whole thing work I was going to need to add a switch to the passenger lap belt buckle as well as add a second wire to the switch. The door switch is a 3-wire switch and the seat belt is only 2 wire. Here's the diagram.
Ass you can see the door switch for the seat belt controller needs to have both an "open" signal and a "close" signal from the door switch, but the lap belt switch is only grounding the signal pin when buckled. Luckily, Honda made the switch with the second position, they just didn't solder a wire in that spot! Here's in the inside of the driver's side lap belt buckle from a donor car.
You can see that the bottom pad is connected to the black wire when the belt is bucked. There's even a hole for a wire to be soldered on. So I verified that I could modify the switch, now I needed to see if I could add the switch to the passenger side buckle. The switch is only held in place by 3 melted plastic posts. The passenger side is a direct mirror of the driver's with the same exact slot and posts.
All I needed to do was solder in the extra wire, swap in the switch into my passenger side buckle and melt down the posts.
Then for the connector. The driver's side is a 6 pin and the passenger side is a 4 pin. Of the six pins on the driver's side, 3 of them are ground and are spliced together later on in the harness. Why waste extra money on a bigger connector to have 3 redundant pins? I dunno, but I just spliced two of the grounds together and voila, now I have room for my extra trigger wire.
Now, when I pull the harness apart, I can rewire the door switch trigger wires to this switch instead. There is a possibility that electronically, the seat belt switch (which triggers the seat belt light in the cluster) and the door switch triggers need to be separate. If that's the case, I'm going to wire in a relay to isolate the two different functions that the lap belt switch is now performing.
Now, the last issue is that the passenger side shoulder belt will always be in the forward position unless I have the lap belt buckled because as far as the controler is concerned, it thinks the passenger door is open. This probably wouldn't bother me all that much and I could just unbuckle it unless there is a passenger, but I want to go the extra mile and have a nice experience with it. So I'm going to add another switch under the passenger seat that is pressed when someone sits in it. That switch can then trigger a relay that will swap the functioning on the passenger side door from wither the door switch of the lap belt switch, depending on if there is a passenger or not. Since the door connector for the 88 is the same as the one for the 90-91, it's just missing the pins for the door switch, I can have both switches on the passenger side. I haven't made that switch yet. I'll be sure to post when I do.
The rest of the job so far has just been systematically going through each connector and wire and splicing them in. It's a lot to keep track of, but if you make yourself a lot of notes and labels, it goes pretty smoothly. It's just very very time consuming.
At this point, I've finished everything for the power mirrors, front doors (windows and locks) and the 7 connectors that needed splicing in for the cruise control. Brake switch, clutch switch, steering wheel switches, main cruise switch, controller module, cruise actuator, and cluster connector.
Remember how I forgot to get that cruise dimmer plug for the gauge cluster? Well that came back to bite me when I had to wire it up. Since the 88 has a completely different dimmer circuit, I had to reverse engineer the pins on the connector to figure out what was what. Here is a bad cell phone video of what I did.
So now I'm working on finishing up the dash harness and amp wiring. That's all for now! Thanks for reading!