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1990 Ford Bronco Question: Keep getting code 42 on KOER test. Changed o-2 sensor. Shows always rich.

 

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R.J.Magellan, Foresthill, CA, October 13, 2013, 15:37
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Trucks been non-op past 6 or so years. Tried inj. cleaner. Checked connectors. Generally seems to run o.k. but still sometimes gets a dirty inj. Don't have a emissions manual or breakout box. Any way to check o-2 sensor with ohm meter?

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  • Answer #1

    G. T. Service Center (4215 Answers) , Stephenville, TX - (254) 638-3236
    ProfessorG October 13, 2013, 16:29
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     Master

    Think you have more problems then an o2 sensor. Leaky injectors/pressure regulator. Trying to remember, Warm up engine - test the gry/lt-blu wire and ground. Idle should be 0.1-0.9v, increase engine speed voltage should increase and decrease as rpms drop. If it doesn't work as stated it's probably bad.

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    R.J.Magellan, October 13, 2013, 17:13
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    Thanks,I'll''give it a try.

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  • Answer #2

    pushrod October 13, 2013, 16:55
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    Full size Bronco? If so which engine?

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    R.J.Magellan, October 13, 2013, 17:20
     Rookie

    Yeah, I thought that info was there. It's a full size Bronco with a 4.9 L 6,5 speed former Forest service vehicle with 85,000 miles.

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    pushrod, October 13, 2013, 17:58
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    Same injector giving the trouble every time? These engines had some connector problem at the injectors. Did you change the fuel filter? How much old gas is in the tank? Don't worry with the code just yet!

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    R.J.Magellan, October 13, 2013, 18:53
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    Yeah. I changed the fuel filter and the #5 fuel inj. was dumping raw fuel but then cleaned up. I changed it anyway but didn't help.

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  • Answer #3

    Greg's Orange Auto (13616 Answers) , Orange, CA - (714) 361-9386
    globalhelper October 14, 2013, 06:00
     Master

    AGREE WITH #1

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