I've got this European 1986 320i, 6 cylinder M20, L-Jetronic (See Sell or fix 325iS, or franken30? http://maxbimmer.com/forums/showthread.php?t=150503
), it runs amazingly rich. Mapping is not possible on the L-Jetronic. The ECU that got this car running came out of Germany and may be expecting a CAT, something that this car left the factory without being as it was destined for Serbia. So maybe the lack of O2 sensor input has the ECU in some kind of warm-up mode at all times? Idle speed drops as engine temp climbs, temp sensor has good resistance. No intake leaks (would show lean anyway), good grounds, new plugs and distributor/rotor.
I've monkeyed with the idle mixture at the air flow sensor but idle still smells like gasoline and after a good drive the exhaust pipe is carbon black.
I'm starting to be suspicious of the cone shaped R*ct*v* air filter installed by one of the POs, gosh knows how long ago. Could it be choking?
I'd like to change it, even though it has no apparent defects, doesn't seem too dirty. I've got the factory airbox so I could go back to that but the cone filter sure makes a nice moan at WOT.
The cone filter has about the same surface area as the factory flat filter and I don't believe in miracles.
Any ideas? Anybody have opinions about air filters?