1997 3.8 V6 running rich

[jasonmreiss]

I need help. 97 3.8 rough idle, blowing black smoke. Fuel pressure around 32ish at idle. No air restriction. Replaced one side o2 sensors. New fuel filter and idle air intake valve. Coolant temp sensor seems to be working. What does that leave me? Thinking stuck injector, pressure bleeds down koeo, but maybe 5 pounds after 5ish minutes.


Cleaned maf as best I could

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[74 Harley]

First question,is your check engine light on? Do you have a code reader? Have you done a compression test recently?
More than likely it will wind up being a sensor.
You may have more than one coolant temp sensor (one for the gauge one for the computer) map sensor could also play a role here.

 

[jasonmreiss]

First question,is your check engine light on? Do you have a code reader? Have you done a compression test recently?
More than likely it will wind up being a sensor.
You may have more than one coolant temp sensor (one for the gauge one for the computer) map sensor could also play a role here.

I do have a scan tool that reads live data. Throwing an O2 sensor code. Coolant temp sensor is providing correct info to my scanner. Intake air temp is as well. Computer is pulling fuel (-20) seems to be the limit of my tool to read. Once it pulls enough fuel it idles smooth for maybe 10 seconds. Then it starts the process over

 

[74 Harley]

A bad O2 sensor can easily be responsible for either a rich or lean condition.

 

[jasonmreiss]

A bad O2 sensor can easily be responsible for either a rich or lean condition.

I am new to fuel trims. I know they should’ve as close to 0 as possible. up stream and down stream seem to be doing things on my scanner. What should I look for to rule them out?

 

[74 Harley]

You said that your scanner shows an O2 sensor code, what does it actually say. Or what is the code number?