Ground loops and 730 ECM

[Vinnie Moscaritolo]

Hi all;

I am in the process of finishing my custom wiring harness to go 
between my 730 and the 1990 TPI (ZZ4) that I am installing into my 
Scout (of all things). Since I am using a fiberglass body, I have 
carefully created a ground bonding post (terminal strip)  on the 
firewall that everything should go to.  In fact the remote  battery's 
connect  there first.  so does all of the ECM connections. I have a 
heavy gauge wire connecting the motor to the bonding post also.

unfortunately the fuel pumps and the alternator ground to the frame, 
but this doesn't really bother me since I am running a heavy gauge 
wire from the alternator to the bonding post also.

There is one thing though that concerns me, its the O2 sensor (Bosch 
12014)  circuit.  Pin E5 of the 1227730 is called out as the O2 
sensor ground.  I noticed that in the 730 it goes to some kind of Op 
amp that reads the sensor, but is in fact isolated from ground.

so my question is how should I handle the 02 circuit? can I connect 
pin E5 to the ground bonding post (on my fiberglass firewall)  or 
should I run a line as close to the 02 sensor as possible?

should I use a different 02 sensor? one that has an isolated ground?

any ideas?



-- 
Vinnie Moscaritolo KF6WPJ ITCB-IMSH
http://www.vmeng.com/vinnie/
PGP: 3F903472C3AF622D5D918D9BD8B100090B3EF042
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