328i Run Crappy During The Day Fine At Night?

[wysockib]

My 97 328i, 4 door, runs like shit during the day when is hot out. At nights when it is cool is runs great. The check engine light come is on, but if I drive at night for a hour or so it goes off. The idol is unstable and between 1-3rmp the power is lacking.

[Delmarco]

Originally posted by wysockib@Jun 10 2005, 01:03 AM
My 97 328i, 4 door,* runs like shit during the day when is hot out.* At nights when it is cool is runs great.* The check engine light come is on, but if I drive at night for a hour or so it goes off.* The idol is unstable and between 1-3rmp the power is lacking.

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Okay....it sound like you have a few problems here
before I start is it safe for me to say that you drive during the daytime with your AC on full blast?

This pulls power from your engine and (although I don't know how or why the E36 are engineered this way) because the AC and other electrical components in your car uses fuel/gas the AC somehow indirectly affects the way your car idles and seems to make the E36 engines (rpms) idle wildly if the AC is on full blast on a hot day.

That is more than likely your problem and that means your Air Flow Meter needs replacing and/or your car's fuel system needs cleaning or servicing or replacing of one or some component.

If I'm wrong about your AC habits then read on.....

1. Check and service your coolant if needed (use ONLY BMW brand coolant or the blue-green watery stuff and NOT the slime-green-toxic glow-in-the-dark-goeeey stuff that you see running out of cheap broken down buicks!

2. Check your auxilary fans and belts to see if they are working. Also service your car for oil and other important engine fluids if needed. Most people forget this.

3. Check all your fuel/air components and replace and/or service any parts of that very very very important system that is DIRECTLY related to how your E36 idles.

4. Also make sure you are putting in 90 or higher grade fuel octane and NOT 87 or 89 grade octane in your tank.

5. Check your AC compressor or freon or the entire AC system to see that all components are fine. Check Alternator as well for wear and tear (i highly doubt it's the alternator though but you never know)

That should be all....unless I missed something....

IMO I highly suspect its your fuel system or Air Mass Meter because these are major causes of idling problems for E36 cars.

BTW...until you fix it I highly recommend winding the windows down and turning off the AC or your engine may die in the middle of traffic whiles idling.

And Finally

[dvmotorsports]

Originally posted by Delmarco@Jun 10 2005, 12:37 AM

This pulls power from your engine and (although I don't know how or why the E36 are engineered this way) because the AC and other electrical components in your car uses fuel/gas the AC somehow indirectly affects the way your car idles and seems to make the E36 engines (rpms) idle wildly if the AC is on full blast on a hot day.

[snapback]352279[/snapback]

Becuase the AC compressor runs off of the Crank Pulley

[Delmarco]

Originally posted by dvmotorsports+Jun 10 2005, 01:59 AM--><div class='quotetop'>QUOTE(dvmotorsports @ Jun 10 2005, 01:59 AM)</div><div class='quotemain'><!--QuoteBegin-Delmarco@Jun 10 2005, 12:37 AM

This pulls power from your engine and (although I don't know how or why the E36 are engineered this way) because the AC and other electrical components in your car uses fuel/gas the AC somehow indirectly affects the way your car idles and seems to make the E36 engines (rpms) idle wildly if the AC is on full blast on a* hot day.

[snapback]352279[/snapback]

Becuase the AC compressor runs off of the Crank Pulley

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[/b][/quote]

okay....but what is the connection with the crank pulley, the AC and the engine rpms at idle? used

i'm curious because i noticed my car does the same thing when i got my AC on full blast...even though my fuel system and Air mass meters are all good. my fuel system my need cleaning though but still....why would BMW link the AC system to the fuel and engine rpms like that? used

[Gkamysz]

okay....but what is the connection with the crank pulley, the AC and the engine rpms at idle?

The A/C takes horsepower to operate. At Idle the engine is making no crank HP. Turning the air on requires torque. The ECM opens the idle control valve a bit to make the needed torque. All vehicles to this, how well it's done varies. My truck shifted completely differently when the A/C was on. It was a pain in the ass. The RPM dropped MUCH faster between gears when the A/C was on. My bimmer is awesome in this regard, shifting doesn't change, the computer makes sure the engine deceleration is the same with or without A/C.

In my car at idle the RPM dip slightly when the compressor turns on. It doesn't vary wildly. I would suspect something is wrong if it does. ICV?

[wysockib]

1. AC is not making a difference, I normal don't use.
2. I always premium gas.

I pulled the check engine codes and got p1250, p0300,p0301,p0304,p0420.

p0300 Random/Multiple Cylinder Misfire Destected
p0301 Cylinder 1 Misfire Detected
p0303 Cylinder 4 Misfire Detected
p0420 Catalyst Efficiency Below threshold (Bank1)
p1250 ?????????


3. Check your auxilary fans (My auxilary is not working at this time!) I think the relay is bad but have been unable to in pen point it.

[Gkamysz]

Missing on cylinders points to the ignition system. If it's been doing this for a long time, I would also guess that the catalytic converter is failing because it needs to burn the unburned fuel in the cylinders.