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89 F150 problem

Discussion in 'Ford Trucks' started by MSC, Nov 23, 2003.

  1. MSC

    MSC Member
    Messages: 75

    I have an 89 F150 here at the house. It's my wife's uncle's truck.
    When cold, the truck spews out black smoke, too much fuel, and it takes about 4 tries to get the truck to stay running while holding the accelerator about halfway to the floor.
    When it finally warms up enought to stay running, it stumbles at idle until you take it for a long ride and clear it out.
    The truck is an 89 4x4 with a 4.9 straight six, auto.
    I scanned the computer and it said loss of signal to pickup.
    Tuned the truck up, plugs, cap, rotor, wires, module, pickup,
    and a temp sensor. tried a MAP sensor that I knew was good,
    and still does the same thing. I am guessing that I may have an injector sticking open, then when the truck warms up, the injector is sticking too. maybe the cylinder is washing down and a good long ride is what it needs to build compession again.
    Any help would be greatly appreciated on this one
    Thanks, Rich
  2. BoulderBronco

    BoulderBronco Senior Member
    Messages: 233

    Have you checked you fuel pressure regulator?
  3. Plow Meister

    Plow Meister PlowSite.com Addict
    Messages: 1,174

    It may be the TPS (throttle position sensor). It may not be working . When you start the truck up like for the first time of the day, the TPS kicks up the throttle a bit to keep it running due to the lack of a choke. If you truly have to hold the pedal down about 1/2 way, there could be all sorts of problems including a faulty injector. You also indicate you have poor compression. Did you test it? What did you achieve? Your valves may also be gunked up and not letting them close properly, thus causing low cylinder pressure and darker smoke and power loss.
  4. MSC

    MSC Member
    Messages: 75

    Did some more checking. Found out that all six injectors were firing with just the key turned on and the engine off.
    This leads me too believe it has a faulty ecm. I did a compression test and all cylinders have good compression. fuel pressure regulator is good.
    Thanks for the help