not sure what engine is in car

[Andy.B]

WRONG. If it's an Eta (1984-1987) it has the small plug. If it's a M20B25 or Super Eta it has the big plug. And there is no 1988 325eS as you mentioned in your earlier post.

And a not to others, the 1987 M20B25 uses Motronic 1.1 not 1.3.

153 dme's are motronic 1.1, and 173 dme's are 1.3.

And I was mistaken on the 88 325es. 88 325e vehicles had the 'super' eta engine in place of the earlier ETA's, which ran motronic 1.1, with a large plug. I mixed up 'seta' with 'es'.

[MR 325]

153 dme's are motronic 1.1, and 173 dme's are 1.3.

You're correct. The 87 cars came with the 153.