does Motronic re-learn optimal idle mix?
 

on my 89 E30/M20, i just replaced:

fuel pump
fuel pressure regulator
fuel pump replay
oxygen sensor relay

now @ start, the car runs (a) a little lower idle RPM, and (b) richer and rougher than it used to.

i suppose different pressures/resistance are possible/likely after the parts replacements. (?)

does Motronic "re-learn" overtime and smooth out settings?

if so, about how long does that take?

if not, what's next to 'cure' the rich/rough idle?

bro,

probably the fuel Pressure not match with the requirement, check it with pressure gauge
hope can give a clue

What do the spark plugs look like? What kind of plugs are in there?

they're "Bosch WR8LC+ Super". pulled 2, look nice & clean.

Those are the right plugs.. This one is really odd. Have you done the stomp test to check for codes?

Pelican Technical Article: Reading BMW Fuel Injection Fault Codes

Did you check the Aux. Air Regulator? Are ALL vacuum lines in good shape?

yep, both the 'stomp test' and my Peak Research R5/FCX too say 'all OK' ...

yep, all vacuum lines are OK.

aux air regulator? new one on me ...
i've an '89 325i E30/M20 auto trans. can you 'point' to what you're referring to @ PelicanParts catalog?

the Aux. Air Regulator is also calle dthe idle control valve. One of the things I like to do is remove it from the intake manifold and spray carb cleaner inside the mechanical portion of the valve. They sometimes stick due to oil residue.

Take a look here.. Number 5

RealOEM.com * BMW E30 325i Volume air flow sensor

ah. i'd already done that ... ICV removed and cleaned. no sticking, no change :-(