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Speeduino – Rover SD1, Four Weeks.

Four weeks, to the day. That’s how long it took from rolling the Rover into the garage with its standard Lucas EFI, and rolling out under its own power with its new Speeduino ECU.
Back in Feb, straight after the British Car Day show, I drove the Rover into the garage and began the Speeduino install. It’s a shame, I do regret not spending more time driving the car when it was running so damn well before pulling it to bits, but I was just so eager to install Speeduino, and I knew I was running on limited time to get it installed and tuned.

Yesterday my awesome neighbour dropped my exhaust back, with the O2 sensor bung welded in. This meant that today, I could crack into refitting the exhaust, and work on finishing the hardware part of the install.

The first step was to get the heavy bloody thing under the car and up into place. This was done with much lifting, lots of swearing, and the help of a small jack to take the weight. I don’t have any photos of this because it was very dirty, hard, work.

This is the result though. A lovely wideband O2 sensor mounted in my exhaust.

I was going to drill a hole in the floor under the center console, but I couldn’t be bothered removing the center console, and since my 14point7 controller is sealed, I chose to install it under the car and run the wiring up into the engine bay and through with the EFI harness. All the wiring is tucked up and protected where I could, as is the controller.

With the exhaust and wideband installed, I moved back onto finishing the ECU and wiring. I have done a lot of work to install new plugs on the ECU end of the loom. I did this as it’s a lot cleaner to work with, and allows me the freedom to easily change ECUs in the future, if I so desire, without having to remove the whole loom.

I also made the hard decision to open up my spare SD1 Lucas ECU, and gut it. I didn’t want to do this, but I had limited choice for an ECU case that had the space I needed, and would mount into the factory mountings.

They are an easy ECU to open. Just six screws and both covers come off. Two of the screws have anti-tamper covers on them, so I used a pair of pliers to grip and turn them. Side cutters snipped the covers off with ease. With the covers off, there isn’t a lot to look at!

It turns out the ECU is a dual board, joined by ribbon cable. Carefully removing the bolts, and small pin in the middle allows you to see what awesome 1980s technology ran this beast.

There is actually a surprising amount of empty space on the secondary board. Lots of unpopulated silkscreen printing. It makes me laugh though, those two boards are huge compared to the tiny little Speeduino boards, and the Speeduino has so much more power!

All of the internal components were carefully packed into an anti-static bag, and stored away safely. At least if im going to use the casing, I refuse to ruin any of the components. It MUST be reversible.

I did some test fitting of the boards to see how they would fit in the casing. Space shouldn’t be too much of an issue 😁

I chose to stick with the red V0.3 board, as I don’t have much faith in my V0.4 board due to its ground plane issues, which I fixed, but im not that happy with it. Im also not a huge fan of the IDC40 connector.

It actually took more planning and work than expected to make it all fit into the case. The wildcard I had not counted on was the USB cable from the Arduino. Despite bluetooth I still needed this cable accessible so I can update the Speeduino firmware in future.

I ended up having to trim away all the strain relief at the Speeduino end of the USB cable so I could bend it 90 degrees. It seems happy enough. The board is mounted to the bottom plate of the ECU with six adhesive standoffs that clip into the Arduino mounting holes. Nice and easy, and gives enough clearance for the bluetooth cables off the bottom of the Arduino.

Speaking of bluetooth, I desoldered the cables I had on the board, and extended them so that the bluetooth wouldn’t be obscured by the metal housing. With all that in place, I buttoned up the ECU, and mounted it to the mounting frame.

These are the bluetooth and USB cables from the ECU, along with an extension for the vacuum line.

Then it was all just a matter of fitting it into place in the car. The loom is a bit of a mess, but it’s safe and all functional. It was just hard to tidy up because of a lack of planning on my part 😑

The ECU frame does have a handy removable access panel, so I could mount the frame and ECU to the body, and tidy up the wiring around it.

I used some seam sealer at the base, just to try to stop it rusting further. When the frame was out, I rust treated anywhere I could see rust, including this foot where the screws go through. That was quite bad, with some perforations.

These are the two new Narva relays. On the left is the main relay, on the right is the fuel pump relay with built-in fuse. These are mounted in the original Lucas relay holders, but with all new terminals. This allows them to mount back in the factory location.

This is the final position of the USB cable and bluetooth with the carpet installed. The Bluetooth is just visible at the top edge of the carpet. Reception seems to be pretty good from that location, and its tucked well up behind the glovebox, out of harms way.

I fully reassembled the interior, refitted the glovebox, and then dropped the car off the stands.

The ECU still responded normally, and now that the hardware was all done, it was time to fire it up and see if I could get the idle in tune.

Initially I was having issues with the idle being rough and fluctuating. It turns out this beast actually needs a heck of a lot of fuel to keep it happy. The VE (volumetric efficiency) table generator well underestimated how much fuel the engine wanted, and it’s happy point was about double what the generator estimated. I also fed it enough ignition advance that it smoothed out the idle, and was running OK.

The next issue I was having was that the moment you loaded it up with the trans by putting it in reverse or drive, the revs would drop and the engine would stall. I did some head scratching, and came to the conclusion that I needed to increase fuel and timing BELOW idle, so that when the revs dropped it would catch them, and bump the revs up. Adding a few points in the VE table, and some advance below the idle cells, and BAM, the bloody thing actually idles smoothly in gear. Amazing!

With it idling in gear now, I couldn’t help but take it for a quick trip down the driveway and back.

For the first time in four weeks, it moved under its own power!

I took it for a quick drive down the road and back. The tune so far is very rough, and its leaning out badly when increasing revs, or increasing throttle. VE Analyze live tuning wasn’t being too helpful either, all it tried to do was take huge steps up to try to combat the leaning out. I think I’ll need to work around that by hand and then use VEAL (VE Analyze Live) for final tweaks and refinement.

There is a lot of work to be done on the tuning, but the fact that the car is drivable is bloody incredible. 😀

I thought that this would be a good point to reflect on what I have actually done in this project.

Wow, what a list. Its been a hell of a lot of work, but now it’s only tuning to do. Something I know nothing at all about, but thanks to the deep end of the pool, I’ll be a damn expert in soon.


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Max Chernotsky
Max Chernotsky
2 years ago

Hey! Great series to follow. I’m looking at doing this with my 3.9 V8 Discovery 1 in the future!

I do have a quick question about the idle stepper controller – what did you do with it? How did you connect it? Do you mind uploading those images of your connection diagram?