Logging fuel pressure and wideband through oil pressure and fuel tank pressure.

[Tbrett]

First off, what I'm trying to accomplish is, is to be able to log fuel pressure as well as my wideband through the ecm and not through the eio. I'm building the harness for my 81 regal turbo 5.3 car right now and I would like to keep it wired through the ecm to keep the wiring cleaner.

As for the OS, I am using a 2005 express van ecm and OS. It seems like I'm limited in 5v pid sources in my application. I am planning on a/c so I would like to keep the ac pressure sensor circuit for that pid. The OS is also going to be upgraded to a 3 bar OS so that eliminates my ability to log egr I thought. I have eliminated the OE oil pressure sensor, so this is possibly an option. The second candidate looks to be the fuel tank pressure pid.

My setup:
-05 express 3500 ecm and OS converted to 3 bar OS
-stock 5.3
-pt7675 turbo
-A/C
-4l80e
-autometer 2246 fuel pressure sender
-ngk afx 96604 wideband



So my questions are:

Has anyone successfully logged fuel pressure or a wideband through the oil pressure circuit?

Can oil pressure volts be logged instead of psi? (It seems like it would be easier to calculate a transfer function if logging volts can be done.)

How about fuel tank pressure? Has anyone logged fuel pressure or wideband through the fuel tank pressure circuit?(evap)

[Tbrett]

ttt..

[prostreet1967]

good question, im in for info aswell. Im pretty sure you can still log off EGR pid with SD. also what sensor are you running for fuel pressure?

[Tbrett]

That would be great if I can use egr with the 3 bar os. When I applied the 3 bar os, the egr enable option disappeared. Maybe we can still log the voltage though?

[jimmyblue]

Your rear O2 sensor positions are always up for grabs, if you
can scale to 0-1V without objectionable noise. Nobody cares
about rear O2 readings for anything, and they may be flapping
in the road draft already.

Now, ground offsets do become more of an issue with lower
ranges and you might need to look at how your fuel pressure
gauge is grounded and whether attaching it raises the O2
sensor ground wire enough to matter. You'd think not, but
assuming is bad (same as your wideband, some of which
throw heater return current back down the same ground
wire as it uses for reference voltage).

[Tbrett]

Your rear O2 sensor positions are always up for grabs, if you
can scale to 0-1V without objectionable noise. Nobody cares
about rear O2 readings for anything, and they may be flapping
in the road draft already.

Now, ground offsets do become more of an issue with lower
ranges and you might need to look at how your fuel pressure
gauge is grounded and whether attaching it raises the O2
sensor ground wire enough to matter. You'd think not, but
assuming is bad (same as your wideband, some of which
throw heater return current back down the same ground
wire as it uses for reference voltage).

That's interesting. I was under the impression they had to be 5V sources.

[prostreet1967]

i think u can still monitor the pid it just wont enable operation

[jimmyblue]

EIO cable can take 0 - 5V (or is it 4V?) but could always be
fed less full-scale, it just costs resolution relative to the
possible maximum. To use the O2 sensors you'd just post-
scale the output with a resistor divider or something. The
wideband I have can be told to use 1V full scale. Its ground
offset is terrible however.

A/C pressure and EGR, I think are both 5V range capable.