delete

Post Mon May 13, 2013 5:53 pm

please delete

Post Mon May 13, 2013 7:09 pm

Ancient versions of the 320 use a coolant heated air slide valve as part of the idle control system and coolant flowing through a transducer is used on the carb. 318, but apart from those two, coolant flow won't have any bearing on idle quality.

Post Mon May 13, 2013 8:09 pm

please delete

Post Mon May 13, 2013 8:26 pm

154 ECU is for the M20B27. Sticking a 173 ECU in there will do nothing other than bugger up your fuelling rates.

Post Mon May 13, 2013 8:35 pm

please delete

Post Mon May 13, 2013 8:47 pm

please delete

Post Mon May 13, 2013 8:52 pm

Unless you live somewhere that get's really cold in winter, the water connections to the throttle body are best left disconnected, and a hose used to bypass them. The heated TB is notorious for corroding and causing coolant leaks, is an unnecessary complication to the engine bay, and actually robs the engine of a small bit of power.
If you have a M20B25 engine, then you need a M20B25 ECU to go with it! Along with a M20B25 AFM.
I'm not familiar with the 154, but it might be that it's the same electrically as the 2.5 ECU except for the main 'chip', and that this 'chip' has been changed for the correct one, in the same way that a 2.0 litre ECU can be used with a 2.5.

Post Mon May 13, 2013 9:15 pm

please delete

Post Tue May 14, 2013 5:12 am

Your AFM is for an M20B25, the ECU is from an M20B27. I'd start investigating carefully over what engine you do really have before investing in other parts because whatever engine swap they did hasn't been done right.

Look on the head for a casting number. If you find "200" you've still got a 325e. If it's "885" then you've got a 325i lump.

http://www.e30zone.net/e30zonewiki/index.php/M20#Head

If that checks out alright then yes, you can just grab a Motronic 1.3 ECU with the correct chip and plug it straight in.