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DISCUSSION => Engine management => Topic started by: stegosaurus on December 10, 2008, 11:13:32 AM

Title: AFM or what?
Post by: stegosaurus on December 10, 2008, 11:13:32 AM

So the other day it was really cold out (10deg.F) and after startup my idle would drop like it was going to stall, and then kick back up. Not a problem when I was driving. I had been stopped at a light and when shifting from 1st it took off into the 4k rpm range when i pushed in the clutch. I let the car roll back down the hill into a bus stop and it wouldn't start. Had it towed and about an hour later it started, but idle would fluctuate between smooth and stalling. I'm thinking this is an AFM issue, what do you think? M42 with 151k on it. What can I do to fix this?

Title: AFM or what?
Post by: bearsbmw on December 10, 2008, 12:22:46 PM

could be Idle control valve,Temp sensor,afm

unplug afm and start the car and report back with idle condition

Title: AFM or what?
Post by: roundel318 on December 10, 2008, 07:38:23 PM

check those hoses, vacuum leaks can also cause your ICV to flip out, besides bears suggestion to check the ICV itself, which ties into some of those hoses :)

Title: AFM or what?
Post by: stegosaurus on December 10, 2008, 07:52:20 PM

Thanks, all the hoses look good (they're new as of April), and the idle seems to have calmed down. That may be because it's warm out today (60F compared to 10F when that whole thing happened). Car still throws the 1215 code.

Title: AFM or what?
Post by: roundel318 on December 11, 2008, 06:43:13 PM

1215 Mass Air Flow Sensor Fault The mass air flow sensor measures the amount of air that is currently being drawn into the engine.  A big hole in one of your fuel injection intake boots may cause the car to stall and generate this code.

Title: AFM or what?
Post by: stegosaurus on December 12, 2008, 01:36:34 PM

Looks like it was the AFM, it's not giving a steady signal through its entire range of motion. Anyone have one for sale?

Title: AFM or what?
Post by: bearsbmw on December 12, 2008, 01:42:11 PM

Quote from: stegosaurus;62704

Looks like it was the AFM, it's not giving a steady signal through its entire range of motion. Anyone have one for sale?

how did you test it??

Title: AFM or what?
Post by: stegosaurus on December 12, 2008, 06:17:42 PM

I used a multimeter from t1-t2, and then I swung the little flap forward and back, I think the manual refers to it as a potentiometer?

Title: AFM or what?
Post by: Eurospec on December 17, 2008, 10:57:22 PM

Quote from: stegosaurus;62704

Looks like it was the AFM, it's not giving a steady signal through its entire range of motion. Anyone have one for sale?

jeremyxman aka deutschman is parting his M42.

He posted a thread HERE (http://m42club.com/forums/showthread.php?t=7493)