[Diy_efi] Bosch L-Jet AFM question...

[Chris Ice]

I'm very confused by something and I'm hoping someone can clarify...

Am attempting to replace the AFM with a MAF sensor (using a signal 
conditioner)...and am not sure how/where to send the voltage.

Pin 6 - as far as I can tell is ecu ground
Pin 7 - afm signal voltage to ecu (at idle, 3.2v across 6&7)
Pin 9 - 12v supply (w/o car running)
Pin 8 - what the frick is this?  7.6v?
(36/39 = fuel pump, 27&6 is air temp...those are easy)

If I simply send signal down pin 7 (leave 8 and 9 disconnected), the ecu 
is clearly unhappy with this and just dumps gas pretty much w/o regard 
to the signal voltage on 7.

I've read in various places that the afm voltage is corrected for dips 
in battery voltage.  If I put a 200 ohm resistor between pins 8 & 9, I 
can get the car to run, but it's now way lean.

Anyone have any insight into the relationship between these 4 pins?  If 
I plug the afm back in, it's all magic...3.2v between 6&7.  But put 3.2v 
down 7 w/o 8&9 and chaos ensues.

Chris
-- 
Chris Ice                    "Laugh'a while you can, Monkey Boy."
http://www.trub.com/                               - Dr. Lizardo



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