E28 will not start..

[henry@xxxxxxxxxxxx (Henry Simpson)]

1985 535i

Is the reference sensor something that normally breaks and is it likely
to be causing my engine not to spark when I try to start it?

I let the car sit for a few months and have 12v at the coil but no spark
(I also checked the coil by swapping it with my other car..

I checked the reference sensor between terminal 1 and 2 for resistance
and think there is an open circuit (it measured no resistance).

Any other important things to look at before I buy parts?

Thank you in advance,

Henry

1990 525i
1985 535i
1988 M3

------------------------------