S13 RB20DET RPM Counter Fix (Pin 7 ECU > Pin 19 Cluster)

Thread in 'Technical Questions' started by silverzx, May 13, 2020.

  1. silverzx

    silverzx Member

    Joined:
    Feb 2, 2010
    Posts:
    540
    Likes Received:
    0
    Location:
    Somerset
    Hey guys,

    Having some issues with getting the RPM counter working on my S13 which has been converted from a CA18DET to a RB20DET. The speedo works along with everything else, just not the RPM.

    Cars been passed around a few DW members over the last ten years and goes as far back to the original engine swapper James_H, project thread found here - https://www.driftworks.com/forum/th...dori-skills-in-and-also-drive-to-work.106087/

    Anyway the problem is the RPM gauge doesn't work, from what I understand RPM is pin 7 on the RB20DET ECU which is red/yellow. I haven't traced the wire the whole way but I believe it's supposed to go to pin 19 on the cluster plug which seems to of been cut and a longer peice of wire soldered on - which goes no where and I assume went to an aftermarket RPM counter once upon a time. I've tried to bridge the connection and still get absolutely nothing.

    Can anyone guide me on what to do next? Obviously I could trace the wire back from the cluster to the ECU but that means unwrapping a load of loom behind the dash which really I'd like to avoid. I could get a temporary piece of cable to run directly from the ECU to the pin 19 on the cluster plug, however I'm fairly certain the existing wire thats been cut (and I bridged) isn't the problem here.

    I've seen a few people posting about putting a 10k OHM resistor on the back of the cluster on here but really wanted to see if anyone had first hand experience and could advise what to try next. Also over on SXOC: https://www.sxoc.com/vbb/showthread.php?573752-S13-with-RB25DET-swap-how-to-get-tacho-speedo-working

    The ECU Octopus Wiring :wack: (showing pin 7 red/yellow RPM)
    ECU.

    The correct ECU diagram (to my knowledge).
    rb20detecu.

    The cluster plug showing pin 19 cut and soldered to a longer piece of wire that goes no where, I bridged these, made no difference.
    plug1.

    The other cluster plug that's irrelevant.
    plug2.

    The current situation.
    interior.

    Someone else postinmg about a similar problem.
    DWThread.

    Cheers everyone! :o
     
    #1 silverzx, May 13, 2020
    Last edited: May 14, 2020
  2. silverzx

    silverzx Member

    Joined:
    Feb 2, 2010
    Posts:
    540
    Likes Received:
    0
    Location:
    Somerset
    I can confirm fitting a 10K ohm resistor on the back of the counter has brought it back to life. Hopefully that'll help someone else one day!

     
  3. membizza s13

    membizza s13 Member

    Joined:
    Sep 24, 2009
    Posts:
    46
    Likes Received:
    2
    Location:
    bath
    Great bit of info, did the same after seeing your post, works perfectly!
     

Share This Page