BUZZING!

It works. It bloody works.

After a frustrating few days with it sort of working, and some minor mishaps (I shorted something on an unshielded 12v connection – but everything seems to have survived). A firmware downgrade (5.05 to 4.96 if you’re interested) has fixed everything. The wheels spin like a dervish now and the motor makes an absolutely wicked noise. My homebrew coupler seems to be doing a decent job too, much to my surprise and delight. I was expecting a lot of vibration and clanking! The clicking you can hear is a loose brake flexi pipe clacking against the wheel (whoops).

Needless to say, my daughter and I are absolutely buzzing. We’ve spent the whole day talking about the all the fun cosmetic bits that now feel much closer.

What’s been done since the last update?

  • Wiring is all finished apart from the fact I need to take the last chockblock out. I’m now confident I have the resolver wired in correctly
  • I’ve tried and failed to calibrate the temperature sensors in the motor by taking resistance readings while pumping through oil heated to a known temperature (and probably ruining a rice cooker in the process). I just couldn’t get stable enough temperature control, and it turns out my oil pump is massively overpowered for the purpose, emptying the rice cooker in just a few seconds.
  • I’ve torqued up all the front end bolts, and finished refitting the propshaft
  • I’ve completed the refurb on the rear calipers
  • The charge port has been installed in the front bumper
  • Discovered the only problem with the electric hood is a flaky switch
  • I’ve changed out the Prius control board (number four?) as I was getting some wonky readings. Turns out this was probably the firmware, but hey, it works now.
  • In the process, I managed to put a hole in the IDC cable that connects the board to the outside world and had to make up another one to keep testing while I waited for a replacement. You see! It’s good that I was still hoarding three old floppy disk cables!
Borked IDC cable…
…and bodged (temporary) replacement

What still needs to be done before I can take it for MOT? This is checklist for me as much as anything.

Battery box

I need to mount the high voltage switch box and the BMS properly in the battery box. This will be done with a thick sheet of MDF for now, with some holes drilled so that it can be bolted down to the protruding screws below which have threaded, socketed heads (scavenged from the original BMW packs).

I then need to waterproof the box a bit better, line the lid, and pack it with some silica gel to pick up any condensation.

HV disconnect

I need to add a safety disconnect for the HV, as at the moment if the contactors welded themselves shut (something I’ve already done to one set) there would be no way to disconnect the battery without a spanner. Still deciding which model to go for, or whether to make one (they are damned expensive – £100-150 for some plastic and copper). This will be bolted on to the side of the battery box.

First sketch of a possible design for a 3D-printed safety disconnect. This one is flawed but I’m already on V2

Relocate the radiator

Dumbass here forgot about gravity, so unless I’m going to seal up the steam pipes on the radiator and add a header tank, I need to move the radiator.

For now it will get mounted where I was originally planning, in front of the charger and inverter. But first, I need to…

Lower the charger

Somehow I screwed up my measurements and the charger sits fractionally too high now, meaning the bonnet doesn’t shut all the way.

There is a relatively straightforward fix which means cutting its mounting frame off, trimming it to fit around the ABS pump, lopping an inch of the legs that support it, then welding it back in again. I think that should fix the problem.

While I have all this out, I’ll give it all a coat of paint. I might clean up the engine bay a bit at the same time. Not to its final state but a bit more presentable.

Hook up the brake booster

I’ve bought a brake booster pump controller from Johannes at OpenInverter, which takes a reading from a standard Bosch pressure sensor and turns the brake booster pump on and off as needed so that it doesn’t have to run all the time. I’ve designed and 3D printed a case for this and mounted it in my fuse enclosure.

I’ve also cut the various pipes to length to connect the sensor, pump, reservoir and booster. Now I just need to put it all together and work out the wiring of the sensor (I can’t find a reliable pinout, though I have had it working before). Unfortunately, the T-adapter I bought that connects the different hose sizes of the various components snapped under the bending pressure of the stiff hose (ooh-er), so I need a better arrangement.

Snapped T-adapter on vacuum line

Make new rear brake lines

I made up new rear brake lines before I refitted the rear axle. Problem: I misunderstood their routing and made them the wrong shape. So need to make up some new ones. I have plenty of pipe and fittings so no biggie. Just need to get around to it.

Refit rear calipers

Calipers are ready to go on and the flexi lines that connect them have been replaced. Problem? I’ve lost the bolts that hold them on somewhere. Need to scour the workshop or get on eBay. Once I have these on I can add some new fluid and bleed the system.

Check ABS works

I suspect the ABS/ASC system may want some communication from the ECU. Hard to be sure when the brake system is in pieces. Once it is all reassembled, we shall see.

Complete rear axle fitting

I had to destroy four allen head bolts to remove the read axle assembly. The first replacements I ordered based on a recommendation from the forums were the wrong size. Second set fit much better. Need to get these in and then get everything torqued up.

Change windscreen wiper blades

Little job, but necessary!

Turn off dash error lights

Various error lights on due to lack of ECU/brake system in pieces. This will take some diagnosis. Still not sure which lights are controlled by CANbus and which (most, I think) by direct 12v signals.

Dash errors

I’m hoping that once the brakes are all reinstalled, all the brake related errors go away, but I suspect the ABS may need a little more than that. Then it’s the EML, which I don’t *think* is an MOT failure, but want to fix.

Make charging work

Not strictly necessary for MOT but I don’t want to run out of juice on the way there. This will be a whole post in itself. Right now, I can’t seem to get either the old car CANbus, or the new EV stuff talking. Even though it worked fine on the bench.

Reroute oil cooling pipework

There are two outlets on the bottom of the motor for oil. I picked the wrong one. So now need to relocate my oil cooler and replumb the system – slightly complicated by this needing different-sized hoses and hence me needing a different-sized connector on my oil cooler. Unless I bodge it together…

Per the note at the start about calibration, I could also do with a controller for the oil pump. This is likely to be as simple as possible for now. Adding in a way to get an external temperature probe in for calibration wouldn’t be a bad idea – maybe using the spare outlet.

Also, when I was trying to calibrate, it leaked like a sieve. So I need to check gaskets and nip up some bolts.

ATF ran out of some of these bolt holes but I found they weren’t actually tight. It didn’t help that my oversized pump put far too much in

Seal charging port

The back of my charging port is currently more open than I would like. Need to remove it to finish the design I have for a cowling that will fit the rubber boot currently on the cable.

Fix power steering return

My homebrew return line for the power steering fouled the bottom of the battery box. I’ve trimmed the battery box support bar but I still need something a bit lower profile.

Tidy wiring and plumbing

My HV wiring all needs securing so it doesn’t flap around, the 12V wiring all needs wrapping in TESA tape, the fuse box needs a tidy up, and the plumbing needs securing as well.

Fix my crap repair

One of the first repairs I did on the car was on the inside front of the sill behind the offside front wheel. It’s crap and needs redoing. I don’t think it’s structural but I don’t need to give the testers anything else to complain about.

Aaaand, that’s it…or is it?

OK, I’ve probably forgotten loads of stuff. I’ve printed off an MOT checklist to help me. The car will almost certainly need a new set of tyres. Obviously I will need to add coolant and check for leaks. And check all the lights work – after the loom has been banging around for a while, some new bulbs will probably be needed.

But I have a list. And I have a deadline. Announcing when I’m going on holiday probably isn’t smart. But let’s just say I have a holiday booked. And I want to get the car MOT’d before we go.

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