Announcement

Collapse
No announcement yet.

ECU running constantly

Collapse
X
 
  • Filter
  • Time
  • Show
Clear All
new posts

  • ECU running constantly

    I've been having a problem lately where my ECU stays running even though my car is shut off. It keeps running down my battery.

    I know it's the ECU because the light on the Romulator was lit up even after the car was shut off.

    Now, this must mean that what is supposed to be switched power is hooked up to a constant.

    The only thing that's hooked up to a constant is pin 114, which I thought was supposed to store codes for the ECU. So, I don't know what the problem is.

    Can anyone help me figure out why the ECU stays running?
    1976 280Z 2+2 Turbo
    '81 L28ET, '84 Turbo ECCS, '84-'85 rotors + Toyota 4x4 front calipers + 240SX rears, Z31 DXD Stage I clutch kit, Evo intercooler, Tokico lowering springs and HP blues
    "I drive an S30...your stock equipment is my future upgrade!"

  • #2
    have you checked your EFI relay?

    In the z31, it "clicks" off a few seconds after the key's turned to off.

    Most z31's do have a battery drain that kills the battery after a few days of sitting. 3-4days usually. I've traced it to something in the EFI harness.. battery lasted forever if you either unplug the ecu, or pull back the entire efi harness off the motor. I've never narrowed it down beyond that.
    vg33et -blew some chunks outta it, then gave it all away.
    2009 370z touring/nav/sports

    Comment


    • #3
      This battery drain is really quick. It takes an hour and the battery is at 4 volts. It used to take a few days. This may be because the battery keeps dying and the life has been compromised.

      In case you hadn't noticed, I use a 1981 280ZXT harness slightly modified for use in a 280Z, which was again modified for use with Z31 ECCS.

      I don't recall a drain problem with the '81 ECCS. I think it's either a wiring mistake, or just a glitch in the ECU.
      1976 280Z 2+2 Turbo
      '81 L28ET, '84 Turbo ECCS, '84-'85 rotors + Toyota 4x4 front calipers + 240SX rears, Z31 DXD Stage I clutch kit, Evo intercooler, Tokico lowering springs and HP blues
      "I drive an S30...your stock equipment is my future upgrade!"

      Comment


      • #4
        280Z Turbo wrote: This battery drain is really quick. It takes an hour and the battery is at 4 volts. It used to take a few days. This may be because the battery keeps dying and the life has been compromised.

        In case you hadn't noticed, I use a 1981 280ZXT harness slightly modified for use in a 280Z, which was again modified for use with Z31 ECCS.

        I don't recall a drain problem with the '81 ECCS. I think it's either a wiring mistake, or just a glitch in the ECU.
        I noticed ;D Unfortunatly, you're only going to get z31 experience here, for the most part... just trying to help ya out with this end of things.

        I'm sure that you have an EFI relay someplace, check if that's frozen hot, or if something's keeping it hot... the ecu should be going down into 'low-power' mode... until the efi relay clacks over. Do you have fusible links? Pull the efi one of those and see if it dies.
        vg33et -blew some chunks outta it, then gave it all away.
        2009 370z touring/nav/sports

        Comment


        • #5
          This source is as good as any for troubleshooting on a hacked-up hybrid like mine! :lol:

          The 280ZXT and 300ZXT harnesses are set up pretty much the same, so just assume that they are.

          I do have an EFI fusible link on the EFI harness and I remember checking the EFI relay when we installed the harness and it worked fine. I tried to start it without the fusible link hooked up and nothing worked except the fuel pump. Like I said, I don't remember having this problem on the 1981 ECCS.

          The only odd thing is that when I plug the battery back in, I hear a faint fuel pump noise for a few seconds. I have my fuel pump wired to a switched + and grounded through the ECU. I noticed that this 84 ECU will never shut off the fuel pump when turned to on, the 88-89 ECU that Jason has will shut it off.

          I suppose this could be an S30 issue, but Jason seemed to think it was the ECU.
          1976 280Z 2+2 Turbo
          '81 L28ET, '84 Turbo ECCS, '84-'85 rotors + Toyota 4x4 front calipers + 240SX rears, Z31 DXD Stage I clutch kit, Evo intercooler, Tokico lowering springs and HP blues
          "I drive an S30...your stock equipment is my future upgrade!"

          Comment


          • #6
            The computer is supposed to run the pump for ~8 seconds at key-on.

            The ecu controls almost everything through providing grounds.

            You might have a frakked ecu...

            pop the cover and check for burned components?

            take a voltmeter/test-light and go play. Figure out what's hot, trace it back to what controls it, and bickety-bam, you'll have your problem.

            Can't be too much help until you go test some stuff.
            vg33et -blew some chunks outta it, then gave it all away.
            2009 370z touring/nav/sports

            Comment


            • #7
              I know very little about electronics, but I did pop open the case and I saw some discoloration on the circuit board right next to pin 114, which is the one I have hooked up to a constant.



              For all I know, that could be normal, but it does look damaged to me. Otherwise, it looks fine inside.
              1976 280Z 2+2 Turbo
              '81 L28ET, '84 Turbo ECCS, '84-'85 rotors + Toyota 4x4 front calipers + 240SX rears, Z31 DXD Stage I clutch kit, Evo intercooler, Tokico lowering springs and HP blues
              "I drive an S30...your stock equipment is my future upgrade!"

              Comment


              • #8
                If it looks damaged, it most likely is....

                Did the constant-hot problem go away with Jason's ECU?
                vg33et -blew some chunks outta it, then gave it all away.
                2009 370z touring/nav/sports

                Comment


                • #9
                  Well, Jason says that the Romulator light wasn't supposed to come on with the key in the off position. However, his ECU WILL shut off the fuel pump after 8 seconds. My ECU has never shut off the fuel pump like that, but I don't see what that has to do with pin 114.

                  BTW, you were the one that traded him that ECU, right? Because we were having problems with that dual serial port USB adapter. My computer doesn't have a driver for it and I can't find one anywhere. If I had the software that came with that USB adapter it would fine.
                  1976 280Z 2+2 Turbo
                  '81 L28ET, '84 Turbo ECCS, '84-'85 rotors + Toyota 4x4 front calipers + 240SX rears, Z31 DXD Stage I clutch kit, Evo intercooler, Tokico lowering springs and HP blues
                  "I drive an S30...your stock equipment is my future upgrade!"

                  Comment


                  • #10
                    Did I not put the box w/ cd in the package?

                    It's just an FTDI based device, these should work for ya

                    http://www.ftdichip.com/Drivers/D2XX.htm

                    I'm betting that it's the D2XX, but if that doesn't work, try these

                    http://www.ftdichip.com/Drivers/VCP.htm

                    WinXP should support it natively... ;D
                    vg33et -blew some chunks outta it, then gave it all away.
                    2009 370z touring/nav/sports

                    Comment


                    • #11
                      280Z Turbo wrote: Well, Jason says that the Romulator light wasn't supposed to come on with the key in the off position. However, his ECU WILL shut off the fuel pump after 8 seconds. My ECU has never shut off the fuel pump like that, but I don't see what that has to do with pin 114.

                      BTW, you were the one that traded him that ECU, right? Because we were having problems with that dual serial port USB adapter. My computer doesn't have a driver for it and I can't find one anywhere. If I had the software that came with that USB adapter it would fine.
                      what do the FSM's say about what 114 does?
                      vg33et -blew some chunks outta it, then gave it all away.
                      2009 370z touring/nav/sports

                      Comment


                      • #12
                        I don't have any Z31 FSMs.

                        I did find that when I plug the battery in, the Romulator light is off. When I turn the key to "ON", the light comes on and won't shut off.
                        1976 280Z 2+2 Turbo
                        '81 L28ET, '84 Turbo ECCS, '84-'85 rotors + Toyota 4x4 front calipers + 240SX rears, Z31 DXD Stage I clutch kit, Evo intercooler, Tokico lowering springs and HP blues
                        "I drive an S30...your stock equipment is my future upgrade!"

                        Comment


                        • #13
                          hrmm, odd.

                          well, check this circuit out maybe?

                          114 is the injector hot wire.. should be +12v.

                          vg33et -blew some chunks outta it, then gave it all away.
                          2009 370z touring/nav/sports

                          Comment


                          • #14
                            ECU shut down

                            You need to be looking at the power relay, what the 88-89 ECU does is a checksum of the memory and stores that in volital ram. The ECU will stay on after the key is turned off for about 5 seconds. Then it will shut down.

                            It sounds like to me that you have bypassed the power relay, in some way that the ECU is getting power from a different source.

                            I am running the 88-89 ECU, and it is a JWT ECU that had the modification to remove the checksum function in the box. Well, I had already made the changes to enable the checksumming in the box. So the first thing I found was that the ECU would not shut down, and the fuel pump, I cant tremember if it shut down or not. But that is where your problems I would be willing to bet.
                            So double check the wiring B+ to the ECU, check the EFI relay(injector relay) and ensure it is shutting down, then check the fuel pump relay as well.
                            I can tell you that you need to provide a ground to the fuel pump relay. The ECU unlike the 280 ECU provides ground to the fuel pump relay, and to the EFI (injector relay) to turn them on.
                            I had to clip one wire on the relays, and tie them into the relay contact wire that was hot all the time.
                            I can also send you a file of the X31 EFI wire harness if that will help. email me if you want @ mailto:mrjeff1@sbcglobal.net

                            Comment


                            • #15
                              Re: ECU shut down

                              jeffp wrote: You need to be looking at the power relay, what the 88-89 ECU does is a checksum of the memory and stores that in volital ram. The ECU will stay on after the key is turned off for about 5 seconds. Then it will shut down.

                              It sounds like to me that you have bypassed the power relay, in some way that the ECU is getting power from a different source.

                              I am running the 88-89 ECU, and it is a JWT ECU that had the modification to remove the checksum function in the box. Well, I had already made the changes to enable the checksumming in the box. So the first thing I found was that the ECU would not shut down, and the fuel pump, I cant tremember if it shut down or not. But that is where your problems I would be willing to bet.
                              So double check the wiring B+ to the ECU, check the EFI relay(injector relay) and ensure it is shutting down, then check the fuel pump relay as well.
                              I can tell you that you need to provide a ground to the fuel pump relay. The ECU unlike the 280 ECU provides ground to the fuel pump relay, and to the EFI (injector relay) to turn them on.
                              I had to clip one wire on the relays, and tie them into the relay contact wire that was hot all the time.
                              I can also send you a file of the X31 EFI wire harness if that will help. email me if you want @ mailto:mrjeff1@sbcglobal.net
                              Well, the fuel pump wiring is fine. The FPR is grounded through the ECU, just like on a Z31.

                              So then where is the +switched on the ECU? I think that is the real issue here because I don't remember the ECU getting any power from that circuit. I know the injectors are run through it, but not the ECU.
                              Attached Files
                              1976 280Z 2+2 Turbo
                              '81 L28ET, '84 Turbo ECCS, '84-'85 rotors + Toyota 4x4 front calipers + 240SX rears, Z31 DXD Stage I clutch kit, Evo intercooler, Tokico lowering springs and HP blues
                              "I drive an S30...your stock equipment is my future upgrade!"

                              Comment

                              Working...
                              X