Where are my Ford experts at?

Discussion in 'The BS Topic' started by AllensaurusRex, Aug 6, 2019.

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  1. AllensaurusRex

    AllensaurusRex Veteran Member

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    Long story short, I have a 2003 Ford Ranger 3.0 2wd that has been in the family since new. Its been a great truck. Around 250k miles, I replaced the heads since these 3.0's have a common valve seat issue and it was burned out. I got another ~75k out of her, and she has been a joy to drive.

    About 2 months ago, I got a misfire CEL on cylinder 4. I did the below, in order, to no avail.
    1. I replaced plugs & wires (tried AC DELCO & Motorcraft)
    2. I replaced coil pack (Motorcraft)
    3. I replaced fuel injector (stock)
    4. Tested compression and was 'OK'. Hmmm...
      1. Around this time, I started getting a misfire on cyl 4 and 6 (WTH!?) :whine:
    5. I pulled the head entirely and took it to a machine shop. He said the valve seat was fine and it held great compression. He also refit the valve seals.
    6. On reassembly, I replaced the head gasket, valve cover gasket, intake gasket, and thermostat gasket. Torqued to spec. All done correctly.
    7. Now I have a misfire on cyl 4, 5, and 6 and a p0300 (or whichever one says misfire on multiple cylinders)
    8. I replaced the upstream o2 sensor
    The truck does run, but like an old 3 legged dog. Definitely running around 65-70% of full power. It's strange because the misfire is ONLY on the driver side bank.

    I took it to a local Ford stealership, and they said they would check timing next if they were me. I guess it is plausible that the timing chain jumped a tooth?...but I wanted to get y'alls thoughts on that before I tear it apart. It's never had the timing chain or waterpump done to date...but just seems a little strange to me that it would run THIS well, at all, with a timing issue.
     
  2. danbrennan

    danbrennan Veteran Member Lifetime Gold Member

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    Could be the timing chain is just stretched, or the timing gear teeth worn, or both. I think the Ford 2003 3.0L is a dual overhead cam engine, with a timing chain. Those overhead cam engines have long timing chains, so they tend to stretch more than the shorter timing chain of a pushrod engine.

    Only other thing I can think of is an intermittent crankshaft sensor, but I would have thought that would set a crank or cam sensor fault. I thought that by 2003 all the OEMs were supposed to set a fault for the timing chain off by one tooth(or more), but I could be mistaken.

    Searching for the fault code associated with a stretched or jumped timing chain, I saw several articles that said one often hears a rattle coming from the front of the engine with a loose timing chain.

    Fuel pressure is okay? Only the misfire codes are set?
     
  3. gramps

    gramps Veteran Member

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    ^ the dohc 3.0 was only in the FWD based plateforms Taurus/escape the rangers had the venerable pushrod 3.0. Although The Taurus was available with both versions of the 3.0 which always makes looking up parts a little more interesting when people don’t know what 3.0 they have in their Taurus.

    If it was a timing chain issue, you’d have misfires on both banks.

    Being that you have checked compression and changed a bunch of parts, before you start throwing more parts in the cannon, have you looked at the data stream (more than a code reader) to see what it says?
    Have you looked at the cat converter on that bank? A plugged or partially plugged cat can cause misfires/driveability problems.
     
  4. frankz

    frankz Veteran Member

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    Sounds very similar to my first Ranger @ 185,000 miles . Turned out to be the computer. Ran like a champ after that.
     
  5. AllensaurusRex

    AllensaurusRex Veteran Member

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    Yes, I will post those later today or tomorrow.
     
  6. AllensaurusRex

    AllensaurusRex Veteran Member

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    Did you end up replacing the entire PCM?
     
  7. frankz

    frankz Veteran Member

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    It was under $100 @ Napa when I did it.........
     
  8. zfool

    zfool Veteran Member

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    Most of the Ford guys are waiting for a tow I suspect.
     
  9. jeff swisher

    jeff swisher Veteran Member

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    And this is why My Fords had carburetors.
    Hope you get it working.
    I had a few computerized swaps way back in the late 90's remove the FI and stick carbs on the engines.
    I have thought many times of doing it to some newer stuff.
     
  10. goofnrox

    goofnrox Veteran Member

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    Yes because the 300K+ miles of reliable operation he got proves the FI to be a terrible Ford FI system. o_O

    Assuming the computer is reporting the misfires correctly, I think the mention about the clogged cat is probably on the right path.
     

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