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a/f turns extreme rich when fans kick on

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  • a/f turns extreme rich when fans kick on

    as soon as my electric fan turns on my idle a/f goes from 14.6 - 12. This is a really sucks What can I do to keep it from doing this I might switch back to the old clutch fan.





    tbs
    Blue & Silver 81 zxt, 88 ECCS
    Z32 mas,450cc injectors
    ported exhaust manifold, cable throttle linkage
    t3/t4e 12psi , 3inch exhaust, K&N,
    ACT clutch, 240sx t/b, 1G DSM BOV
    Custom Intake FINISHED
    Ported and Polished N42
    Tan 88-89 conquest seats
    Sperco IC 18.5x6x3.5
    2.5 IC pipes
    Suspension work!!
    Nistune
    Zeitronix Wideband
    240sx transmission
    Soon:
    95 Maxima Alternator

  • #2
    Strange... where is your MAF mounted relative to the fan, and how much piping does it have between the filter/maf?

    Comment


    • #3
      The filter is infront of the radiator about 3 inches and the fan is on the back side of the radiator. I'm also rich though out the driving range as well not just at idle. I'm thinking that it might be voltage load causing the car to run differently it doesn pull around 25-30amps. I'm going to try putting back on my factory clutch type and see if it goes away.





      tbs
      Blue & Silver 81 zxt, 88 ECCS
      Z32 mas,450cc injectors
      ported exhaust manifold, cable throttle linkage
      t3/t4e 12psi , 3inch exhaust, K&N,
      ACT clutch, 240sx t/b, 1G DSM BOV
      Custom Intake FINISHED
      Ported and Polished N42
      Tan 88-89 conquest seats
      Sperco IC 18.5x6x3.5
      2.5 IC pipes
      Suspension work!!
      Nistune
      Zeitronix Wideband
      240sx transmission
      Soon:
      95 Maxima Alternator

      Comment


      • #4
        Are you logging MAF voltage at the ECU? You might see if it changes when the fan turns on. Might be something as simple as a non-shielded maf signal wire?

        Comment


        • #5
          I'll double check when I get home and see what the signal is before and after.





          tbs
          Blue & Silver 81 zxt, 88 ECCS
          Z32 mas,450cc injectors
          ported exhaust manifold, cable throttle linkage
          t3/t4e 12psi , 3inch exhaust, K&N,
          ACT clutch, 240sx t/b, 1G DSM BOV
          Custom Intake FINISHED
          Ported and Polished N42
          Tan 88-89 conquest seats
          Sperco IC 18.5x6x3.5
          2.5 IC pipes
          Suspension work!!
          Nistune
          Zeitronix Wideband
          240sx transmission
          Soon:
          95 Maxima Alternator

          Comment


          • #6
            ok here is the log before and after the fan kicked on. my maf volts increased from 1.25-1.33 most of the time and spiked to 1.45 volts and afrs went from 13.s to 11's. is this an interference problem or what? I might just pull that fan off and go back to clutch style.








            tbs
            Blue & Silver 81 zxt, 88 ECCS
            Z32 mas,450cc injectors
            ported exhaust manifold, cable throttle linkage
            t3/t4e 12psi , 3inch exhaust, K&N,
            ACT clutch, 240sx t/b, 1G DSM BOV
            Custom Intake FINISHED
            Ported and Polished N42
            Tan 88-89 conquest seats
            Sperco IC 18.5x6x3.5
            2.5 IC pipes
            Suspension work!!
            Nistune
            Zeitronix Wideband
            240sx transmission
            Soon:
            95 Maxima Alternator

            Comment


            • #7
              `

              Comment


              • #8
                Yup, it's most likely a maf signal interference issue IMO. As for exactly WHY your maf voltage increased on account of the fan, I can't tell you... but I would guess it's electrical interference (noise/crossover current) between the wiring or some kind of noise the fan is making. Check the voltage output and supply at the maf as well and see if it changes by the same amount, that will tell you if it's in the maf output (signal) wire, or something interfering with the power getting to the maf.

                Is your maf signal wire running in to the ECU shielded? Where are your e-fan wires routed? Maybe you have another e-fan you could try to see if it's electrical noise from that fans particular motor? You might even be able to build yourself a passive filter and still use that fan if it is indeed electrical noise causing the voltage change.

                Who knows though, I could be way off.

                Comment


                • #9
                  ok I'll check out my voltages at the mas. my mas wire is shielded I'll double check the shielding to make sure its grounding. I'll also try it there with and turn off the fan to see if that helps. the wires for the fan run from the battery through a relay to the fan and ground back at the battery. Bernardd I'll send you an email shortly.




                  tbs
                  Attached Files
                  Blue & Silver 81 zxt, 88 ECCS
                  Z32 mas,450cc injectors
                  ported exhaust manifold, cable throttle linkage
                  t3/t4e 12psi , 3inch exhaust, K&N,
                  ACT clutch, 240sx t/b, 1G DSM BOV
                  Custom Intake FINISHED
                  Ported and Polished N42
                  Tan 88-89 conquest seats
                  Sperco IC 18.5x6x3.5
                  2.5 IC pipes
                  Suspension work!!
                  Nistune
                  Zeitronix Wideband
                  240sx transmission
                  Soon:
                  95 Maxima Alternator

                  Comment


                  • #10
                    I'm just coming in from playing with the z. and its got to be something with the fan no matter what temp I turned it on at my cars a/f's increased. I also checked for the mas shield and it’s there and has continuity with the ground. What electric fans is everyone else running? I don't know what mine is its some mystery fan that I bought so I don't know. My solution is to pull out my fan and go back to the clutch style.




                    tbs
                    Blue & Silver 81 zxt, 88 ECCS
                    Z32 mas,450cc injectors
                    ported exhaust manifold, cable throttle linkage
                    t3/t4e 12psi , 3inch exhaust, K&N,
                    ACT clutch, 240sx t/b, 1G DSM BOV
                    Custom Intake FINISHED
                    Ported and Polished N42
                    Tan 88-89 conquest seats
                    Sperco IC 18.5x6x3.5
                    2.5 IC pipes
                    Suspension work!!
                    Nistune
                    Zeitronix Wideband
                    240sx transmission
                    Soon:
                    95 Maxima Alternator

                    Comment


                    • #11
                      yes it could be introducing a voltage ripple.... one more reason to use a genuine oem fan, any car manufacturer will pick better stuff with better thermal and power characteristics than an aftermarket like flexalite or permacool

                      with the quest alternator, I can turn on the maxima fans, no lights dim, the voltage stays dead on as if nothing happened

                      jason was using a camry fan, others have used honda, chrysler and ford fans with good success... go junkyard hopping

                      Comment


                      • #12
                        do you guys have any years for those fans?
                        also how big is the z31 rad? This is the problem when talking z31 for the ecu and running it on a s130.



                        tbs
                        Blue & Silver 81 zxt, 88 ECCS
                        Z32 mas,450cc injectors
                        ported exhaust manifold, cable throttle linkage
                        t3/t4e 12psi , 3inch exhaust, K&N,
                        ACT clutch, 240sx t/b, 1G DSM BOV
                        Custom Intake FINISHED
                        Ported and Polished N42
                        Tan 88-89 conquest seats
                        Sperco IC 18.5x6x3.5
                        2.5 IC pipes
                        Suspension work!!
                        Nistune
                        Zeitronix Wideband
                        240sx transmission
                        Soon:
                        95 Maxima Alternator

                        Comment


                        • #13
                          turbobluestreak wrote: do you guys have any years for those fans?
                          also how big is the z31 rad? This is the problem when talking z31 for the ecu and running it on a s130.



                          tbs
                          Mine is off an early 90's Toyota Crammy V6. It's wired on high and I can honestly say it moves at least as much air as most "high performance" aftermarket fans. It only covers about 2/3 of the radiator (I think it's right around 14x16), but that's apparently all that's needed to keep my engine running perfectly cool in even the hottest weather.

                          You could actually get any OEM fan that fits right and moves enough air, just bring a tape measure and some wire to test them while you're there. A buddy of mone got his off a Ford Tempo, and it had a shroud almost prefectly fitting to the Z31 radiator.

                          Z31 Radiator Dimensions:
                          Core Size: 16 1/8" x 25 3/8" x 1 1/4"
                          Top header: 1 1/2" x 25 5/8"
                          Bottom header: 1 1/2" x 25 5/8"
                          Inlet kneck diameter: 1 3/16"
                          Outlet kneck diameter: 1 3/16"
                          Rows: 2
                          Mount type: Bracket/Pin Mount
                          Distance between transmission oil cooler fittings: 11 3/4"
                          Construction: Copper/Brass

                          Comment


                          • #14
                            thanks! I'll start the search for a new fan and untill I find one I'm going back to the factory fan.




                            tbs
                            Blue & Silver 81 zxt, 88 ECCS
                            Z32 mas,450cc injectors
                            ported exhaust manifold, cable throttle linkage
                            t3/t4e 12psi , 3inch exhaust, K&N,
                            ACT clutch, 240sx t/b, 1G DSM BOV
                            Custom Intake FINISHED
                            Ported and Polished N42
                            Tan 88-89 conquest seats
                            Sperco IC 18.5x6x3.5
                            2.5 IC pipes
                            Suspension work!!
                            Nistune
                            Zeitronix Wideband
                            240sx transmission
                            Soon:
                            95 Maxima Alternator

                            Comment


                            • #15
                              Mine are off of a lexus um...gs430? Some v8 toyota car platform. I don't know if that helps. OH, and they are supposed to be pusher fans, so I messed up on that one.

                              Terrible idea putting those wheels on...

                              Comment

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