Annoying Problems and Thanksgiving Maintenance!

[bmwman91]

The car has started to develop some quirks in the past few months, so I am finally going to try to address them.

1) For one, the gas mileage has been steadily decreasing from ~30mpg to an all-time low of 24mpg.  Some of this is the winter-blend gas probably, but it began decreasing before winter.

2) Another one is a loss of power at part throttle below ~4k RPM (intermittent, mostly when cold).  It does not stall or stutter, but the thing feels totally gutless, and once I hit ~4k RPM it suddenly GOES!  I suspect that the ignition coils are going south again.

3) I seem to consume roughly 1 quart of oil every 2000-2500 miles.  The motor bleeds oil, never leaving drips on the ground, but the thing is soaked & gross.  Some of this is probably just from running synthetic.

4) Sometimes when the motor is running, I can hear a nasty clunking/metallic banging noise coming from the motor when standing by the hood.  It seems to be coming from the front, outside the motor itself (accessory pulley or something).  It MIGHT be the viscous fan clutch.  I noticed that the fan spun freely (no resistance) when the motor was off, and 5 minutes later the clutch seemed to be working marginally.  Hopefully the noises (which have stopped for now) were just the fan clutch dying.

5) There is a small rust hole under the battery tray.  Grr.  The fuel lines around the tank/filter are old & a little cracked.  I should probably replace those.

6) I get a CEL if I drive the car hard.  It does not perform any differently when the light turns on.  The only stored code is 1221 (EGO sensor heater system).  This has something to do with the LC-1 wideband system I installed.  As far as I can tell, there is no power loss to the module, so perhaps the sensor is dying again (these stupid things only last 1 year at best).  The car DOES feel a little more sluggish than I remember, but who knows.

7) Overall, I seem to be running rich.  If I am at WOT above ~5k RPM, I see black smoke come from the exhaust.  This is mainly due to the MAF conversion that I need to finish tuning.  Still, even at warm idle the exhaust smells a bit rich.  This could be related to #6.

Gas pedal/cable binds up from time to time.

9) Noisy motor on colt starts.  It sounds like a sticky lifter sometimes, and a little bit of diesel-motor noise.  The diesel sounds are bad, and most likely from the chain tensioner piston (it now has 50k miles on it...what's the life expectancy of that?)

10) The gears grind sometimes when shifting.  I think that there's air in the clutch system and/or the cylinders are pooping out.  The shifter is also super sloppy and feels like it is hitting something.

So, to address some of this, I have ordered the following:
- Bosch LSU4.2 UEGO sensor
- Bremi ignition coils (M54) & resistor boots
- Fan clutch
- Fuel filter (will buy some fuel line once I figure out what size I need...any tips?)
- Air filter panel
- Throttle cable
- Spark plugs
- Timing chain tensioner piston
- Clutch hydraulic hose
- Clutch master/slave cylinder rebuild kits
- Z3 short shift kit
- Magnetic oil pan drain plug (just in case...)

> I am really HOPING to fix #1 with these parts (mainly ignition & EGO sensor).
> Problems #2, #6 & #7 are likely linked to #1.  I DO need to re-tune the MAF conversion though.
> Issue #3 is most likely only going to be fixed with a rebuilt motor (mainly re-honing the cylinders & new pistons/rings, and new seals all around).
> I plan to address #5 with some weather stripping adhesive, a plastic body plug and some PVC undercoat paint.
> I am crossing my fingers that the nasty noise in #4 was indeed the fan clutch.  It is dead anyway, so this should be replaced. Otherwise, it is coming from the PS pump, alternator or water pump...eek.
> #8 is easily fixed with the new cable.
> I am not sure how to deal with the sticky lifter (rebuild head?), but the tensioner should get rid of the bad diesel noises.
> #10 should be easily resolved with some help form the shifter/clutch parts I bought.

Aaaah the joys of running a 20 year old car!