From: tangen_at_nbserv2.dseg.ti.com (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?
[ Help ]
80 coupe, running a little rich, afm nine clicks
tighter, now watching the tailpipe deposits