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1973 KE20 + SR20DET Build

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Thought I might share my build on here since I really have to date not published this build log.

So attached is a write up that was done on the car a year or so ago and will take it from there going forward.

So the reasoning behind me joining up for the courses at HP academy is the car has always lacked any attention to wiring which has become increasingly frustrating so I have started the process of stripping out the entire wiring loom from the car and beginning from scratch.

This will include some upgrades for the next certification as mods have been done since it was last certified.

- Rewire entire car with new Link ECU

- Setup overflow protection under the new fuel tank

- Rework dash and relocate or expose individual cylinders for pedal box

- Reconfigure brake hard lines to be more visually appealing

- Clean, prep, repaint engine bay and radiator support

- Finish boot installation for new battery box, fuel system, subwoofer

Attached Files

First post, current progress.

- Removed all bodywork forward of the doors

- Removed Intercooler, radiator, oil breather

- Removed and stripped dash

- Documented and bagged dash loom, gauge loom & fan loom

Progress over the weekend.

First up, the random mystery wire. Initial comments I received about this wire was that it was running from the starter to the reverse lights. Makes a little more sense now but still wonder why corners are constantly cut.

So the cleaner looking section with red and black wires (under the multimeter) are spliced with a nice open barrel splice into the mystery wire running under the car and earthed by the tail light barb rather than the factory rear loom earth point. The purpose of the ground was only to remove the factory ground and create the new one.

The function of this red wire however is reverse switch signal. The wire under the car goes to the gearbox sensor.

57 Year old toyota factory rear tail light loom, Has strain relief! Thought this was an appropriate image for this forum.

For reference, the start of the boot reconfigure.

Wee update from the weekend. Cleared out all things that were in the way.

This will result in pulling the engine and transmission for an engine bay tidy and repaint. Making sure to clear out all previous owners mistakes.

Started the mockup of the fuel system in the boot. Trying to get the filter and pump under the floor so I have room for new Moroso battery box and subwoofer. Car is being built as a weekend toy not all race and not all show.

The stock wiring harness for this car. To say it is in bad shape is an understatement. Each owner has obviously added just a little to it each time and never really removed anything that wasnt required. Wires spliced into other wires running in all directions and tucked behind the dash so no one could see. Glad it is finally all out!

Always nice to see a clean build like this! Keep posting!

Do you plan on reusing the OEM Fuse/relay box or you plan on going aftermarket?

Awesome build Brian! Love the old Toyota's.

Can't wait to see more!

Frank, I am looking at options right now. Most likely end up with a PDM like this one (well at this point it is the leading contender)

I do have budget in mind with my selections as well as the end use for the car. Going to a new ECU and PDU I deemed not necessary for this car. For the same reason there wont be tefzel wiring rather than going to the TXL.


Looking at ways to mount bulkhead connections and relocate the brake and clutch cylinders I think I will look into a pair of blanking plates to cover alot of the factory mounts and conceal all the hardware that bolts the pedal box to the firewall.

(Lockdown means I have no access to real materials so I have to resort to cardboard)

Hey Brian

That PDM is exactly what I had in mind when I asked ou the question! I’ve never worked with it yet, but next build I do I’ll definitely use this one. I got a quote last week from my supplier for one of these actually!

Keep up the good work!


PDM''s are such a great way to simplifying wiring and systems. Also with some systems that you can CAN bus most statuses to switch on fuel pumps, fans etc it really reduces the need for output wiring.

Also having the functions of circuit resets, current draw logging and a huge amount of actuator condition functionality. We are seeing more and more being used in applications coming through the shop. Although these PDMS come at a decent cost.

I have never seen that style PDM before, looks like an awesome piece of kit! Might be something we need to add as an option.

In regards to the tefzel wire, have you done a comparison on price? We found with the right supplier there wasn't much of a price difference.

Hey Chris!

Yeah, it’s not solid state though. It’s basically a Fuse and Relay box, but it does the job for simple cars!

We could discuss if it’s a real PDM, well... it does distribute power! Lol

Yeah i have researched a decent PDM with a CAN bus interface and unfortunately with all the other little add ons I want to do in this round it is just not going to be viable. I have thought ahead and I think I will create a sub harness for this one for now so that I could plug n play a decent one in at a later date. Advantages of completely overhauling the wiring.

The development for the car is only aimed at being an absolutely reliable street conversion. Added power is just a side effect of the conversion so I am balancing that against costs.

I am recording detailed list of invoices for the wiring job so that I can concisely say how much the wire job cost me. I have a few basic tools already but mostly buying everything I will need from scratch so a good learning experience I hope to share with others.

First package.

Sargent 1026 CT Crimp tool.


4 x injector, 1 x bosch water temp, 1 x cam angle sensor, 1 x Alternator

Some M10x35mm Ring terminals for miscellaneous earths and power cables

Second piece of kit to come, Brother PT-E300VP label printer. This is capable of printing on the heat recoverable materials. So will clearly label my harness as per the recommendation of the Club sport wiring course. (side note I found this as the model being demonstrated in the wiring course is discontinued).

This is an inspiring build...

Thanks isaac.

Next delivery arrived thanks to prowire usa.

22awg wires and 1/4" kapton tape.

Still piecing together the supplies for the wiring job.

Few more pieces starting to arrive now. Always wanted a top Mount setup so brought a sinco manifold which arrived this week, so tweaking needed for wastegate location but pretty stoked.

Also picked up some smaller hand tools for working on my wiring harness, still more tools to come.

In other news I decided to try and reduce the load on the cars electrical by changing the rear lights to led. I intend to rewire the light holder to have a dtm plug rather than use the factory plug. More to come on this as it will be the first part of the wiring harness to be put together.

Final layout decided for the boot, just the fab work on the whole install to begin there.

Few more pieces turned up. Rope for mockup harness, SCL heat shrink and universal open barrel crimp tool.

Also planning on moving the existing hard brake lines so needed some tools. Bending tool and deburring tools.

Got to get the final mockup of the fuel system right before I cut out my new floor. Stainless steel box to be recessed into the floor with a perspex window just for show. Lots of options but getting closer. More fittings needed!

Flaring tool kit for brake lines. All the tools I am loving it!

Few more things happening.

Started to clean and rewire the led lamps into my tail lights. Going to a hell of a lot more reliable than they were with very little drain on the power system.

Also got the power distribution block from littelfuse for the rear of the car.

The most exciting news my ECU is now here so moving forward with the engine harness once more wiring supplies arrive.

Updating the switch panel with something cooler. So I picked up these two buttons for mock up and will order the rest once i know all of what i need. That horn tho!

So progress on this is slow with limited time.

Finished off the tail light re-wire and LED treatment which all things considered went pretty good (missing the cable tie strain relief in these pics)

Put some of the club sport wiring course to the test after having a wee play with the tail lights. So started the boot loom.

Followed the HPA steps so things went great. Note the black marks on the wires. Poor mans wire identification (couldn't justify the colored heat shrink bands even though I really wanted them) hahaha

You can buy packs of differently coloured tie-wraps - try Repco or Jaycar, I bought some years ago but can't recall where - and if you need a greater range, double them up with other colours.

Ah - https://www.jaycar.co.nz/100mm-coloured-cable-ties-pk-125/p/HP1196

@Gord Yeah lots of other good options. This is a simple boot loom which has a limited number of connections so is pretty easy.

Was tempted to use different wire colours too but just rolled with this. (getting a feel for what it will be like to do the rest of the car)

So this update might not be too interesting to most but I get alot of satisfaction from following the course to reality.

Finally sorted all the final components for the rear loom and installed it. One small piece of the puzzle but found all the pitfalls of using these materials, plugs and sheathing.

This was a stroke of luck and advice from another Forum member @RobJ. Jiffy plugs to sort my number plate lights.

Terminated Loom


Terminating to a cable that was run a while back to accommodate the replacing the rear wiring.

Testing the LED light quality. My phone couldnt even see any clear distinction of the lens the light is that good.

Lastly I have the label printer and clear now sorted for when I do the power distribution at the front and the engine loom.

I have acquired a solid state PDM for the car which will be the next update. So glad I stuck to my initial wants.

Confidence it starting to peak so best I get on to the engine harness now.

So planning. Engine harness mock up done.

So fun times ahead, went and pulled the trigger on the Eaton Bussmann PDM module mentioned earlier. Decided this is ideally what I wanted for this build at a fraction of the cost of the non solid state PDM modules around. Effectively this is a pre-configured power distribution block which has enough circuits in it to do what I need it to do.

I have also laid out my mockup harness onto a bench in order to check that I have all the required plugs and have cut all my wires to length in order to start completing this part of the process. At the point below I had not recieved the eaton gear so how it branches on the cabin side is yet to be decoded.

Nice to see it's progressing well! Keep up posted!

Thanks Francis.

Old story, to make an omelette first you must break some eggs. So Trial and error on spares I brought to practice with.

First up the Denso Injector plugs. One with crimping the wire seal with a round die and the other with the tanged die. Seems both work fine but the tanged grabs the wire insulation much better.

Then the Metripack connectors for the Eaton gear.

22awg wire is a little on the small size the wire seal and these terminals. I found a happy medium in that the PDM is internal of the car and won't see too many harsh environments. So the round die for the wire seal did the trick using the larger #5 die followed by the smaller #1 die to overlap the tangs a little. So here are the results.

Two on the left I tried to use the tanged die which resulted in crushing rather than folding the wire seal tangs over. The middle one is just using the #5 round die which allowed me to pull the wire seal out so failed the tug test.

Forth one was using the method I explained above, #5 followed by #1

Fifth sample was 18awg wire which was just perfect right from the get go. #3 for the wire crimp. #5 for the wire seal.

Excuse my awful hand writing on this, trying to sit at a desk and write on the wall effectively.

Next is the IAT needed to move from where it was fitted to a more appropriate location. My ecu literature and all advice I could find suggested after the intercooler and prior to the throttle body was the ideal place for the sensor not into the intake manifold which is where mine was previously fitted. Decided to ditch the GM IAT sensor in favor of the recommended Bosch IAT sensor so once that arrives I will get it fitted in the intercooler pipe as shown here.

Once the sensor is mounted it is the last piece of the puzzle on this part of the engine harness so I will make a start on final assembly.

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