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  1. #11


    You don't have to worry about the crank sensor -- they didn't put them in until 1996.
    If it's running that rich still, the only other thing I can think of is your oxygen sensor. Luckily, that's easy to change, and if you're really lucky, it's the 20-dollar one-wire unit. If it's stuck sending a lean signal, it can make your engine use a horrendous amount of gas.

  2. #12


    Ya, this 1-ton does not have an o2 sensor.
    Blanks on the hole or sensor.
    Been looking at that since the beginnning but there was never any sensor or hiring harness

    ---------- Post added at 03:30 PM ---------- Previous post was at 03:28 PM ----------

    exhaust with straight pipes + H-pipe.

  3. #13


    Look about six inches in front of the catalytic converter. They weren't all on the manifold. It does have an O2 sensor. They've had them since the 80's.

  4. #14


    Ya, it must have been deleted then...only an H pipe and flowmasters.
    NO harness wire can be found though...dangling or otherwise...

    Sure they had em on the 1tons?

  5. #15


    Yeah, I've seen a few of them. You must have one of the weird ones. :3
    Well, two other things I suppose you could try...
    Replace the fuel pressure regulator diaphragm. That's pretty cheap and easy to get.
    Try also, unplugging the vacuum hose from the EGR valve and block it off. See what happens. That's a long shot, though.
    Last edited by Chris Miller; 07-26-2011 at 11:58 AM.

  6. #16


    Pretty sure those don't have a crank sensor. Sounds like the ECU might be running in limp mode, or that your pressure regulator is bad. Didn't see but have you checked your fuel pressure yet? High pressure = more fuel through the injectors.
    1986 Chevy G20 Tow Rig - 5.7 TBI conversion
    1978 Mustang II King Cobra Road Racer - Holley 650, MSD 6AL, 5 speed, 10 point Roll Cage, 9" posi, fuel cell, custom interior.

  7. #17


    Yes, replaced the regulator, new Computer, New IAC, TPS, MAP...after the new computer, new plugs and wires...spray is finally a fine mist, truck starts right up...but now the idle RPM flutters from 800ish...holds then jets up to 1500 then back down...up and down up and down.
    I'm gonna try the EGR vacuum and reseting the idle screw procedure again...
    if that doesn't work...maybe try drilling in an O2 sensor and wiring it to the COMPUTER....just will need to find out what wires would hook into the computer to do that.
    But that would be a long shot for sure esp when there wasn't an o2 on this truck.
    Definitely have one of the weird ones im thinking...but its making progress at least.
    ANy other thoughts?

  8. #18


    After the new computer went in...and new wires and plugs again...ran good. Still surged up on idle though...up and down. Turns out it was the thermo sensor on the front top of the block/head. Tellin' the computer that the temp was -30deg so it was attempting to warm up or something like that.

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