Fail, but in a bad way

I went into the first MOT test with genuinely zero expectation that we would pass. I needed a to-do list but there were some things I thought would rule out a pass first time. So when we failed so narrowly, I was elated.

Going into the retest I was much more nervous. It felt like there was a real chance we would pass. I was infected with hope. As you may have guessed from the title of this post, that hope was swiftly dashed.

Things started well enough. The drive over started great, with the car feeling much more planted, the brakes now being on good form, and the tuning I’d done making it much more lively. There was only one event where we suddenly lost torque but it came straight back.

But the closer we got to the MOT station, the more the occasional squeak from the engine bay that had appeared on the previous visit became a persistent squeal.

Handing the keys over to the mechanic, he took it for a short drive down the road. It stalled and wouldn’t restart. And that squeak just got louder.

Between the stall, the squeak, and the fact that my eyeballed attempt at tracking was off the mark, he refused to do the retest saying he couldn’t be confident the car was safe for the road.


So, we brought the car home again for more work. The tracking is simple enough – I got the wheels straight relative to each other but didn’t realise you also needed to align the steering wheel so that it is ‘straight’ when the wheels are straight. I was going to leave that to the professionals once I got the car good enough for the road. Rookie mistake. Lesson learned. But the drop-out events and the squeak are much more of an issue.

I decided to turn my deflated frustration into motion and set about stripping the whole lot down to find the cause of the squeak. A little testing had made it very clear it was coming from the coupler that sits between the motor and gearbox. I had always been aware this could be an issue but in all my early testing, it seemed to be fine. Only when it had been driven under load a couple of times did its weaknesses become apparent.

Removing it means taking almost everything from the car: draining cooling loops, stripping off the front bumper and valance, dropping the battery box, jacking up the transmission, disconnecting low and high voltage wiring, removing the inverter and charger, and unbolting the mounting frame. Only then can you split the motor from the adaptor plate and remove the coupler.

Sure enough, it is bent. In rotation, one end clearly moves back and forth by at least a millimetre. And at least one of the splined clutch centres is not square. Whether it was when I first put it in, I just don’t know. After all is was made with a hammer on a Black and Decker workmate, not in a proper machine shop. I thought it was good enough but clearly not.

The hard truth is that I’m not going to get in for a retest within the ten day limit. Instead, I’m going to have to send the coupler off to a machine shop. And then hope that when it returns, the motor will still bolt up to the adaptor plate once it is properly aligned with the gearbox. It will be September before I can try again.

In the meantime, I hope I can resolve the tuning issues and understand why I’m losing traction. And sort out the issues with the battery management system that have left me charging manually.

Until next time…

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