Fucking EDIS no spark

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    Fucking EDIS no spark

    Vehicle '95 Ranger so no external EDIS module, the coil driver is integrated into the ECU.

    Scanner shows a PIP signal. Key On Engine Off test shows only emissions related faults, no misfires or anything related to the ignition system.

    I have confirmed the harness wiring for the crank position sensor circuit (would be no PIP without it anyway), the harness wiring for the ignition circuit and that there is an AC signal present on each of the pins corresponding to a coil when cranking.

    Coil is from a '00 Taurus instead of a Ranger but I don't think that should matter.

    I have played musical coils with three coils (one of which was running this engine before I swapped it out of the Taurus it came in) and three ECUs, same results.
    I can smell fuel in the exhaust so it's getting something.

    I have confirmed with a spark tester followed by my hand that I am in fact not getting spark on any cylinder.

    To make this more confusing, at one point I mashed 2/3 of the coil circuit pins when playing musical ECUs resulting in it running on two cylinders.

    The fuck am I missing?

    Yes I know I should have just slapped megasquirt on it but that ship has sailed.
    Last edited by arse_sidewards; 05-23-2020, 11:53 AM.

    #2
    Which engine?

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      #3
      3.0 v6

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        #4
        Did you check the negative side of the coil for a trigger signal?

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          #5
          What do you mean negative side? Like the ground? What kind of signal should I be looking for?

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            #6
            Originally posted by arse_sidewards View Post
            What do you mean negative side? Like the ground? What kind of signal should I be looking for?
            There's 4 wires on your coil pack. One is 12v power the other 3 are ground circuits. Are they triggering?

            Edit: also, are you getting 12v to the power wire?

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              #7
              Originally posted by Will12785 View Post

              There's 4 wires on your coil pack. One is 12v power the other 3 are ground circuits. Are they triggering?

              Edit: also, are you getting 12v to the power wire?
              12v is present on the red wire. No voltage or change between ground and the other three while cranking. No resistance change between ground and the other three while cranking. It's like it's not even trying to fire the coil. I verified continuity between the three coil pins and the corresponding pins on the ECU connector for the millionth time and they're still good.

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                #8
                Originally posted by arse_sidewards View Post

                12v is present on the red wire. No voltage or change between ground and the other three while cranking. No resistance change between ground and the other three while cranking. It's like it's not even trying to fire the coil. I verified continuity between the three coil pins and the corresponding pins on the ECU connector for the millionth time and they're still good.
                12v in and no voltage on any of the 3 signal switches sounds like a bad relay.

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                  #9
                  Spend 30min digging around for the full fuse box from a formerly running driving Taurus that I knew I had somewhere. Spent 5min playing musical relays. No change.

                  Here's the screenshots from when I was playing musical ECUs on Saturday. Basically the same codes for emissions stuff I don't have regardless of ECU. One of the ECUs shows a fuel pump code but the pump is clearly running and providing fuel. It cranks around 250rpm. PIP signal looks good.

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                    #10
                    The PIP is only going to signal your injectors. The spark signal comes from the crank position sensor to the ecu. I would test the cps. When cranking the signal from the cps will bounce between .5 and 1v AC. You could also test the injectors if you have an NOID light which will help rule out the ecu.

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                      #11
                      Originally posted by Will12785 View Post
                      The PIP is only going to signal your injectors. The spark signal comes from the crank position sensor to the ecu. I would test the cps. When cranking the signal from the cps will bounce between .5 and 1v AC. You could also test the injectors if you have an NOID light which will help rule out the ecu.
                      I thought PIP was used by the ignition system.

                      I don't see how the crank signal can't be good since I get PIP and RPM which are dependent on the ECU knowing the engine is cranking. I will check it though.

                      I've played musical ECUs. At least 1/3 has to be good. One of them briefly ran the truck back when I had bent a couple of the coil pins (which also helps rule our crank).

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                        #12
                        At this point I would say its a wiring issue. You've got a lot of wiring related codes so its possible something got messed up.

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                          #13
                          At this point I'd put a scope on the CKP circuit at the PCM connector and crank on it. Make sure you can see the missing tooth in the waveform and that you aren't just getting noise on that circuit when cranking.

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                            #14
                            Originally posted by Will12785 View Post
                            At this point I would say its a wiring issue. You've got a lot of wiring related codes so its possible something got messed up.
                            No shit sherlock, I butchered a '94 harness to make a '95 harness and left out the emissions stuff I wasn't planning on using. The question is which circuit is the one that's fucked in a way to keep it from starting. None of the emissions stuff should do that.


                            Originally posted by WhiteTrash303 View Post
                            At this point I'd put a scope on the CKP circuit at the PCM connector and crank on it. Make sure you can see the missing tooth in the waveform and that you aren't just getting noise on that circuit when cranking.
                            Funny you mention that. I almost bought a scope at the start of this project. Any old antiquated scope I bought of CL should do the trick, right? I don't see why I'd need any modern features to look at a low voltage AC waveform.

                            You might be right about the noise. I omitted the shielding from the last foot or so when I made that circuit of the harness and I didn't twist the wires like they do with the VSS circuit. I figured that since nobody runs the shielding on the crank sensor for aftermarket EFI it would be fine. It did run once with this configuration so who knows, maybe having 3/3 of the coils plugged in instead of 1/3 is giving it enough noise to cause problems since those circuits run parallel in the harness.

                            That said if I'm getting noise there wouldn't it prevent the PCM from knowing that the engine is turning which would cause it to not send anything out on the tach pin?

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                              #15
                              Clip the wires for 2 of the 3 coils. And see what happens.

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