Author Topic: Bad air flow meter? (Read 3391 times)

detoxed · « **on:** December 30, 2010, 09:29:23 AM »

My 91 318is has developed a intermittent miss/ power loss at highway speeds (60-80). The stomp test shows 1215 code- afm issue. Are there any other tests or things I should ck. before breaking the bank for a new or reman. afm? Bone stock other than COP.
Thanks

DesktopDave · « **Reply #1 on:** December 30, 2010, 10:29:54 AM »

Check to see f you have the BMW resistor pack installed. It's a little extension in the AFM harness. I had the same 1215; once I pulled that connector & drained the water out it ran just fine & cleared the code.

BTW, an early 525i (89-90 M20 motor) or any OBDI e36 (92-95 M42) use the same AFM IIRC.

detoxed · « **Reply #2 on:** December 30, 2010, 11:35:47 AM »

No resistor pack. Guess I'll head to the pnp, take a look around.
Thanks

DesktopDave · « **Reply #3 on:** December 30, 2010, 11:38:47 AM »

Before you condemn it, I'd pull the cover off & see if the sweep arm has worn a path out of the resistor board. IIRC that arm can be adjusted to fix it.

detoxed · « **Reply #4 on:** December 30, 2010, 03:47:00 PM »

OK, found and read the FRWilk article on afm's noting the refurbish part ie moving the contact arm plate north or south to move the contacts onto fresh contact material. Problem is the plate appears to be pressed onto the shaft unlike what is shown in the article where the plate can be adjusted by loosening the clamping bolt and sliding the plate up or down on the shaft ie north/ south.
Any suggestions? New afm's are pricey.

DesktopDave · « **Reply #5 on:** December 30, 2010, 08:22:23 PM »

Hmmm. Never took apart an e30 AFM. The earlier M20 arm is removable.

Can you press it any further?

Ryann · « **Reply #6 on:** December 30, 2010, 09:36:33 PM »

I have occasionally had this EXACT same issue during long freeway trips. As Dave said, after unplugging/plugging it in it went away.

detoxed · « **Reply #7 on:** December 31, 2010, 07:07:05 AM »

Going to hit the pnp. If I can find an afm that can be used to experiment with I'll see if it is possible to adjust.

DesktopDave · « **Reply #8 on:** December 31, 2010, 07:56:15 AM »

The earlier cars have a different connector, inline instead of round. Other than that I suspect they're the same internally. Some other models also have adjustable CO2 screws.

The M30 AFM is supposed to be a decent upgrade M20s, I suspect it'd work out for our cars too. If you find one I'd grab it any way, they usually go for $70 or so.