1997 Ford Ranger Oxygen Sensors

Tiny
WORTHIN52
  • MEMBER
  • 1997 FORD RANGER
  • 4.0L
  • 6 CYL
  • 2WD
  • AUTOMATIC
  • 150,000 MILES
I replaced both oxygen sensors a few months ago and I still get error codes for both of them and my check engine light comes on. If I unplug the sensors or plug the bungs how will the truck run and will the check engine light stay on?
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Wednesday, December 3rd, 2014 AT 7:22 AM

19 Replies

Tiny
HMAC300
  • EXPERT
Yes the light will stay on and your fuel mileage will drop significantly. Have a pro check it as it may not be the sensor but a shorted wiring problem or even a pcm which if bad he will have to program.
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Wednesday, December 3rd, 2014 AT 8:34 AM
Tiny
WORTHIN52
  • MEMBER
Thank You
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Wednesday, December 3rd, 2014 AT 8:59 AM
Tiny
JOHNNYT73
  • EXPERT
May I ask what the codes are? Are you getting actual voltage codes for the sensors, or lean/rich codes?
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Wednesday, December 3rd, 2014 AT 9:09 AM
Tiny
WORTHIN52
  • MEMBER
I don t remember the complete number I would have to do a scan again. What I can tell is it comes up lean bank 1 number ending 171 and lean bank 2 number ending 174. Here s the other thing I only get these codes and the check engine light comes on only when the temp outside gets below about 50 Fahrenheit. I drove the truck all spring and summer never got the error codes and the check engine light stayed off. I have replaced the temp sensor in the air breather tube between the throttle body and mass air flow sensor. When it comes to sensors and solenoids related to fuel and emissions I have replaced them. I have checked for vacuum leaks and exhaust leaks and can t find any. I have been working on cars my entire life and this one really has me stumped.
Thanks Todd
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Wednesday, December 3rd, 2014 AT 9:48 AM
Tiny
JOHNNYT73
  • EXPERT
That tells me there is nothing wrong with your o2 sensors. If they are reading a lean/rich mixture that tells you have issues elsewhere. If the sensors were bad you would be getting a voltage code for the sensors. Its saying your engine is running lean. I know you checked for vacuum leaks, but I would search around more with spraying some throttle body cleaner. Check your fuel pressure to make sure you are getting proper fuel. You can try some injector cleaner to clean out injectors to be sure your getting fuel delivery. Maybe even try a fuel filter. Remove throttle body and clean both sides and IAC port. If you have a scan tool to read live data I would check all your temp values on all sensors to be sure everything is working well (ECT, IAT, ambient air temp).
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Wednesday, December 3rd, 2014 AT 10:04 AM
Tiny
WORTHIN52
  • MEMBER
I have not taken the throttle body off of the intake but I have cleaned it. I have also run fuel system cleaner through my gas tank several times. The truck starts like it should and it doesn t run like its starving for fuel and my gas mileage is good. I had the fuel tank filler tube replaced about a year ago because the rubber was cracked. My gas cap is new and fits tight. I am not familiar with what normal sensor temp readings should be.
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Wednesday, December 3rd, 2014 AT 10:45 AM
Tiny
JOHNNYT73
  • EXPERT
I would check for vacuum leaks again when the engine cold so you know that no gaskets had a chance to swell and seal from the heat.
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Wednesday, December 3rd, 2014 AT 10:48 AM
Tiny
WORTHIN52
  • MEMBER
I will do that.
Thank You
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Wednesday, December 3rd, 2014 AT 10:57 AM
Tiny
JOHNNYT73
  • EXPERT
Check PCV hoses and the valve itself. Check fuel supply manifold gasket (fuel rail to manifold gasket) as a common issue for these motors.
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Wednesday, December 3rd, 2014 AT 11:03 AM
Tiny
WORTHIN52
  • MEMBER
I have replaced PCV valve and hose. If the fuel rail manifold gasket was leaking would I smell gas?
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Wednesday, December 3rd, 2014 AT 2:21 PM
Tiny
HMAC300
  • EXPERT
Fuel rails have orings so if you smell gas it may be something else.
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Wednesday, December 3rd, 2014 AT 3:34 PM
Tiny
WORTHIN52
  • MEMBER
I do not smell gas. I thought maybe if the fuel rail o-rings were bad I would smell gas and that might help me pin point the problem.
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Wednesday, December 3rd, 2014 AT 3:44 PM
Tiny
JOHNNYT73
  • EXPERT
http://www.2carpros.com/questions/1997-ford-ranger-rough-running

This has been answered before. There is TSB for the PAPER fuel rail manifold gasket. Follow the link.
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Wednesday, December 3rd, 2014 AT 4:01 PM
Tiny
WORTHIN52
  • MEMBER
I have listened for vacuum leaks and felt all around the intake manifold and everywhere else for vacuum leaks and I don t come up with anything. I will try again.
Thanks
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Wednesday, December 3rd, 2014 AT 4:14 PM
Tiny
JOHNNYT73
  • EXPERT
To be honest almost all vacuum leaks are ones you can't hear. If it's not something obvious. Just follow the link I posted and then gentleman with your issue has posted the TSB word for word.
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Wednesday, December 3rd, 2014 AT 4:28 PM
Tiny
WORTHIN52
  • MEMBER
I just checked for vacuum leaks again. I cannot hear anything or feel anything and I checked every place. I have owned this truck for 2 years. The person who owned this truck must have had it worked on. It looks like someone has had the intake off before. I found small chip in the plastic where the throttle body mounts to the intake. I could actually see the rubber gasket. I also found a chip in the plastic where the idle control valve mounts to the intake. I repaired both areas. I don t know if they were part of the problem or not. Like the saying goes when you buy a used vehicle you re buying someone else s problems. That s true with this old truck.
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Wednesday, December 3rd, 2014 AT 6:12 PM
Tiny
JOHNNYT73
  • EXPERT
Trying to listen for a vacuum leak can really be wasting your time. You need to get a can of throttle body cleaner and spray around the intake and all lines/hoses. IF you hear the idle change then you know you found something.
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Wednesday, December 3rd, 2014 AT 6:17 PM
Tiny
WORTHIN52
  • MEMBER
I have done that before but it s been many months ago. I will have to get another can and try it again.
Thanks Again
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Wednesday, December 3rd, 2014 AT 6:30 PM
Tiny
JOHNNYT73
  • EXPERT
How are things with the truck?
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Tuesday, January 27th, 2015 AT 7:03 AM

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