Engine will runs rough and stumbles, smell fuel at end of exhaust?

Tiny
RANGERSHANE
  • MEMBER
  • 2002 FORD RANGER
  • 4.0L
  • V6
  • 4WD
  • MANUAL
  • 200,000 MILES
Engine will runs rough and stumbles, smell fuel at end of exhaust. Replaced exhaust components to fix exhaust leaks and still have issue. No vacuum leaks found with smoke test. Replaced upstream oxygen sensor twice on my passenger side. Traced wires from connector to as high as I could get towards the engine bay to look for damage, no damage. Inspected all large wiring harnesses/wires and connection points for damage, no damage evident.

Back probed blue/orange lead to pcm: 8.7ohm on one pin, 4.4ohm on another with key off.

Back probed white/black lead to pcm: 12.4ohm on one pin, .3ohm on another with key off.

Brown/orange connector: 12.4v key off

Blue/red connector : 11.8v key off

I have a scan tool that can pull all of the live data and upload that to here or pass off the information. As far as I can tell bank 1 sensor 2 seems to vary in voltage what seems normal to me and bank 1 sensor 1 has differences in reading than bank 1 sensor 2. Any insight would be great, thanks for your time.
-Shane
Friday, April 23rd, 2021 AT 10:46 AM

3 Replies

Tiny
ASEMASTER6371
  • MECHANIC
  • 52,797 POSTS
Good afternoon,

The downstream O2 voltage should be steady and not vary like the front.

The heater should have 12 volts with the key on at the light blue/orange wire. Then the ECM grounds the circuit for the heater to work.

https://www.2carpros.com/articles/how-to-check-wiring

https://www.2carpros.com/articles/how-to-use-a-voltmeter

Verify that voltage. I attached diagrams for you. Fuse 41 in the underhood fuse block supplies the voltage.

https://www.2carpros.com/articles/how-to-check-a-car-fuse

Roy
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Friday, April 23rd, 2021 AT 1:16 PM
Tiny
RANGERSHANE
  • MEMBER
  • 46 POSTS
12v at the fuse with key on, as well as 12v at the blue/orange wire with key on.

Also my mistake I was referring to my bank 2 sensor 1, not the downstream bank 1 sensor 2 like I had previously explained.

-Shane
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Friday, April 23rd, 2021 AT 6:49 PM
Tiny
ASEMASTER6371
  • MECHANIC
  • 52,797 POSTS
The results are still the same. The heater circuit is controlled by the ECM.

12 volts from the fuse and the ground controlled by the ECM.

Roy
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Saturday, April 24th, 2021 AT 2:09 AM

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