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From: (Eric Tangen)
Date: Thu, 5 Dec 96 10:26:28 CST
Subject: <question> 02 sensor open loop and air flow meter cal

Has anyone out there with an l-jet (or flapper afm motronic) motor done the following?:

Step 1) broke the 02 connection to the ECU

Part B) put +500 mV (approx lamda=1) on the 02 line to the

         ECU (to 'close' the loop and force the ECU 
         not to correct the injector pulse width). (resistance
         looking into the o2 connection to the ECU is
         > 100 kohms, so no real danger of hurting the ECU 
         by doing this.)

Section iii) proceeded to recalibrate the flapper air flow

             meter (by changing the afm spring tension 
             using voltage readings from the 02 sensor)?

this is a little different from the method described in the October Roundel, where you use an averaging DVM to determine if your running rich or lean and look at the voltages on the 02 sensor with the loop closed. as i don't have an averaging DVM, i dreamed up this method last night in the garage, but didn't implement it yet. thought i'd pass it by by comment.

another observation: with the 02 sensor disconnected, the voltage readings on my 02 sensor where always .800-.850 mV no matter how much I leaned out my air flow meter by increasing the spring tension. seems like this should be typical open loop behavior. or is this anomolous?

eric tangen
80 coupe, running a little rich, afm nine clicks tighter, now watching the tailpipe deposits

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