Flywheel ring gear

[johnb]

When you ask how the screw lines up -- you mean the relationship between the ref sensor pin and the ring gear teeth? Other than accommodating other models, nothing obvious comes to mind about the half-tooth delay. The phase seems to be fixed by the hardware, so I can't think up an scenario where it would change on a running car...? I'll have to read your write up to understand the other quirks you mention...

Yes that's what I'm asking.

I suppose the same Motronic system was used on other cars too, and maybe some of those cars has press-fit ring gears without any particular timing guarantee.

The diagnostic pin thing is interesting. Does that have something to do with that other sensor, with the connector on the back of the cam tower? I always wondered what the deal was with that. I tried checking it for a signal before and didn't get anything.

[Tom]

When you ask how the screw lines up -- you mean the relationship between the ref sensor pin and the ring gear teeth? Other than accommodating other models, nothing obvious comes to mind about the half-tooth delay. The phase seems to be fixed by the hardware, so I can't think up an scenario where it would change on a running car...? I'll have to read your write up to understand the other quirks you mention...

Yes that's what I'm asking.

I suppose the same Motronic system was used on other cars too, and maybe some of those cars has press-fit ring gears without any particular timing guarantee.

The diagnostic pin thing is interesting. Does that have something to do with that other sensor, with the connector on the back of the cam tower? I always wondered what the deal was with that. I tried checking it for a signal before and didn't get anything.

I'll take a look (and some pics) in the morning. Yes, the extra pin on the flywheel is for that diagnostic connector -- vestigial hardware of no use outside the basement of the Bosch diagnostic equipment museum...