I hooked up a code reader. An old cen tech from harbor freight. I didn't have any cel or trouble codes. Just wanted to monitor live data. I found that my O2 voltage was at 0.00 volts. It never changed. Any leads to what I should be looking for? I see that I have 2 O2 sensors equipped on my 1997 ford ranger xlt 4x2 automatic with 4.0liter v6. Please help. Any and all advice is appreciated.

 

You actually have 3 O2 sensors on a 1997 4.0l Ranger

Two upstream O2s, one on each exhaust manifold pipe
And a 3rd back farther after the Cat Converters to test if Cats are working, called downstream O2

O2 sensors won't/can't work until they are heated up above 600degF, so can read 0v for first few minutes, after warm up they should change voltage FAST, within .2 to .7 range

O2s are the only sensors that can "wear out" they use a Chemical reaction to measure Oxygen in the exhaust, and they run out of chemicals after about 125k miles or 10-12 years which ever comes first
When they run out of chemicals they can go to 0v even after they are warmed up

The downstream O2 lasts twice as long as Upstream, because it sees less Oxygen, Cats use up the Oxygen

O2 sensor's voltage will set trouble codes instantly if there is a problem because these are Emissions sensors
You don't mention any codes, so could be an OBD Reader Error if there are no O2 sensor codes

 

I do see that I have three O2 sensors now that I was able to get a better look. Well, the scan tool is cheap, but it reads voltage on the 02 bands for my friends Dodge Hemi. He thought it was his scanner as well not reading with my pcm, but it reads his voltage when we hooked it up to his truck. I am having no cel, but driveability problems under hard/heavy acceleration at operating temperatures.

 

I am looking into Forscan and an elm327 usb adapter...

 

The Bluetooth OBD2 are cheap and work fine for most people, assuming you have a cellphone that can use APPs

But Forscan is a really good software and the ELM327 is a good interface, but wired, so not as easy to use while driving

 

I haven't spent a dime yet towards the elm327 adapter. I have only downloaded the free version of Forscan. What route would you highly recommend? The Bluetooth obd2 reader or the Forscan route?

 

Forscan allows you to change some things, "talk to the PCM", two-way communications, but not a programmer

OBD readers just "Listens to the PCM", one-way, which is fine for diagnostics

Either is fine to get the data needed by the MAIN computer, YOU