Starting, or not

"Cé hé sin" (michael-m-mouse) 06/02/2018 at 07:46 • Filed to: Smart Roadster, Torx

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Your correspondent is told by the internets that poor hot starting is likely to be caused by a dodgy crank position sensor, like this:

So I’ve invested a modest sum in one. Sadly though it has to be fitted as well, which involves starting above the engine and removing bits until you can kind of reach the existing unit, extracting a T30 bolt, extracting the sensor itself and finally getting the new one in and reversing the procedure. All of these stages can go wrong, not least in getting out a bolt that has been sitting there rusting away quietly for fourteen years so I’ve been told that the cheapest option (the official way is to drop the engine) is to use a ball headed T30 bit, like this:

First tool shop I went to expressed some surprise that such a contraption would actually do the job asked of it but once I swallow enough brave pills we’ll see.

BvdV - The Dutch Engineer > Cé hé sin 06/02/2018 at 08:08

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Never knew ballheaded torx bits were a thing, you learn something new every day, I guess.

Good luck on replacing the sensor, let’s hope Mercedes Benz was just overly concerned with the ergonomics of their mechanics when they decided that dropping the engine is the way to do it.

Cé hé sin > BvdV - The Dutch Engineer 06/02/2018 at 08:13

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Purely by chance, I saw a set on sale somewhere recently but I didn’t need them then!

Echo51 > Cé hé sin 06/02/2018 at 08:23

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Good luck. Depending on engine/position, you might be lucky and the screw isn’t stuck at all, but i found the plastic sensor housing to really be tight in the bores. But since you have a new one, just pry it out, who cares if you break the tabs and mangle it!

Cé hé sin > Echo51 06/02/2018 at 08:25

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I’ve read horror stories of the sensor having to be drilled out....

Echo51 > Cé hé sin 06/02/2018 at 08:35

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Before ford grew some sense and started using plastic housings on their ABS sensors, they used a thin steel cup as the tip. Which sits in the metal hub. You can guess how fun those are to get out :)

Jayvincent > Cé hé sin 06/02/2018 at 10:17

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Bad Crank position sensor will also cause your car to spontaneously shut off while you are driving it... ask me how I know :) Good luck with replacing yours

Cé hé sin > Jayvincent 06/02/2018 at 15:26

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Yes, that happened twice today! The first time I had to sit there on a busy road cranking for ages.

I tried and failed to buy the ball point torx bit.