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OT It just won't fire!

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  • OT It just won't fire!

    OK folks, I really need some help. we changed a valve cover on my son's 88 Ford Ranger, 2.9 V6, Fuel injected truck. Now the coil will not fire. We have installed a new coil, Rotor, Distributor cap & wires to no avail. Its getting voltage from the ignition switch but turning over the engine doesn't fire the engine. Could it be the ignition module in the distributor? Could there be a sensor somewhere the ground between the distributor and the coil that keeps it from switching on and off? Anyone with any ideas except the ones mentioned, please chime in, we are at our wits end. What about the things mentioned that we haven't done? Thanks, Gene

  • #2
    I forgot to add that my son disconnected the positive side of the battery instead of the ground side when he began. Could it damage the ignition module in the distributor if it maybe shorted on something? Gene


    • #3
      IF it ran before you messed with the valve cover. I would look at any connections that might have had to be unplugged to get at the valve cover.

      Disconnecting either battery terminal would not cause this.


      • #4
        If you have actually pulled a plug, grounded it, and confirmed that there is no visible spark when turning the engine over, then I would suspect the ignition module. If the engine fires on a shot of starting fluid but won't stay running, I'd suspect the fuel pump. My mom's '95 Escort had a reset switch for the fuel pump, which I discovered when after working on it I couldn't get it to start. I might add that I have no idea what caused it to trip.
        Last edited by x39; 05-01-2008, 07:07 PM.


        • #5
          Certainly possible ...

          Is this TBI? Is the distributor rotor turning when the engine cranks? Is there high voltage going to the distributor? I'm not familiar with fords and I don't know the ignition set-up on an 88 ranger.

          If it's not a mechanical system (which I doubt it is on an 88) then you'll need to check all the electronics. There is usually a hall-effect sensor or an "electronic eye" and a shutter wheel to turn a circuit on or off. You'd want to check the condition of the trigger wheel in the hall-effect pick up or the shutter wheel on the "electronic eye" type. If the spacing is incorrect or the wheel damaged it could cause some issues.

          Remember that with most digital circuitry in autos, the voltage needs to be 5 volts or ground, in between and the electronics don't know what to do.

          First step is to see where the problem is. Have you got high voltage to the distributor? If not, then go to the coil input - have you got a square wave 12 volt input? You'll need an oscilliscope for that. Umm ... i'm forgetting something big here ... but its dinner time ...


          • #6
            Own one myself,the truck uses a TFI ignition system (Thin Film Ignition).This is the module on the side of the dist.Chances are you guys have something disconnected,could be the plug on the module,or the SPOUT circuit which is actually part of the computer ground.

            Knowing the truck if you changed the valve cover gaskets you had to unplug the engine wiring harness and seperate several connectors in order to do it.I would start there first.Look for something that got missed.

            It is possible that the module has gone south,but if it was running before the gasket job it should run after.

            The good news is the modules are cheap now and any module of the same type off any Ford TFI system will work 4,6 or 8 cylinder.If you buy a new one get either a Wells or a Borg-warner module,well worth the extra money.
            Last edited by wierdscience; 05-01-2008, 10:26 PM.
            I just need one more tool,just one!


            • #7
              I had the module go out on mine, did the same thing.

              For a while before then, it was spotty when it rained or got too humid as well.

              Good luck getting that module off, here's a hint, chuck your socket in to your lathe and turn it down a little bit. I think it's 8mm.


              • #8
                Did you check your valve covers for pinched wires.I know of a car that had the job dune by a well known shop that did that.Had a hard time tring to find out the motor backfired until it blow the muffler and also quit.I found the coil wire pinched under the valve cover.


                • #9
                  Here's a far out one for you. Check your fuel impact shut off to see if it was enabled during the repair. If this was set off, you are not getting fuel. This is under the dashboard on the firewall either on the drivers side or the passengers side.

                  On almost any FI car, there is one of these that shuts off when something is played with in the engine or an impact is had. I have seen these go off in Rangers by just curbing a tire, and have seen them switch off during my own repairs. I also just went through enabling this (shutting off fuel pump and flow) doing the fuel filter. I also believe these things go out when the electrical system has been interferred with.
                  CCBW, MAH