ECU Codes + Parts

Discussion in 'Technical' started by Hellsheep, Aug 25, 2016.

  1. Hellsheep

    Hellsheep Administrator Staff Member

    Messages:
    244
    Likes Received:
    32
    Trophy Points:
    28
    Hey all, continuing to work through the issues with my Zed, it's going pretty well now however a few new issues have popped up.

    Code 21 Primary Ignition Circuit, looks like from what I can see it's likely PTU/harness that's dodgy and will need to be replaced, also from what I've read it's common for the PTU's to die.

    Code 13 Coolant Temp Sensor, so I've played around with the temp sensor and the wiring looks a bit dodgy/loose on the connector going into the sensor, and it looks like someone has previously put some black electrical tape around the contacts. I assume that it's been dodgy before and a simple fix was for them to do this. I suspect the best thing to do would be to replace the harness (or put a plug on it if there is meant to be a plug of some sort?) and sensor for good measure just in case the sensor itself is faulty?

    Looks like CarCraze sell Series 2 PTU's so I'll likely get one from there and get an auto electrician to do the plugs for me as pixie wrangling is definitely not my strong point!

    Looks like they also sell the coolant temp sensor. Just need to know what sort of plug should be on the end of the harness for the temp sensor as from what it looks like right now the contacts just push straight into the orange connector on the sensor side?
     
  2. Fists

    Fists Well-Known Member

    Messages:
    1,453
    Likes Received:
    34
    Trophy Points:
    48
    If all of your loom is starting look dodgy I would suggest looking into a EFI harness from wiringspecialties.com The price is up there a bit, especially factoring in shipping and exchange but if you plan to own the car for 5-10+ years it's a sound investment, you'll easily spend more by the time an autoelec has fixed every dodgy trace in the 25 year old unit. There are some fitment 'quirks' since they're derived from LHD cars but fully functional and good piece of mind.
     
  3. rob260

    rob260 Moderator Staff Member

    Messages:
    13,250
    Likes Received:
    276
    Trophy Points:
    83
    Location:
    Sydney (North)
    Also there are diagnostic procedures for your error codes in the EF & EC section of the manual http://www.300zx-twinturbo.com/cgi-bin/manual.cgi -if you have the time and a $20 digital multi meter you can do a thorough diagnosis before replacing any parts
     
  4. Hellsheep

    Hellsheep Administrator Staff Member

    Messages:
    244
    Likes Received:
    32
    Trophy Points:
    28
    Cheers checked the price and its reasonable. I do need to replace the knock sensor also and I guess now is the time, harness, knock sensor. Not sure I am going to have the time to do this myself however as it looks like a pretty lengthy job. I suspect it's much easier to take the engine out or apart to do the harness? Which plenum pull will be required for the knock sensor anyway?

    I agree it's a much better investment to do the job right the first time and whilst I'm not sure how long I'll have this car for its definitely a car I'm passionate about.

    Will do this, got a multi meter so I'll go through this over the next few days.
     
  5. Hellsheep

    Hellsheep Administrator Staff Member

    Messages:
    244
    Likes Received:
    32
    Trophy Points:
    28
    Did some further testing last night/today. Didn't have the multimeter, I have another Zed sitting around in pieces so I took the Series 1 PTU from that, I knew it was working before I pulled it apart. Check engine light now gone and Primary Ignition Circuit codes gone from ECU too.

    Fiddled around a bit with the coolant temp sensor, confirmed it's missing the connector from the harness side and is just contacts with electrical tape that's probably not too good plugged into it.

    I can reproduce the thermo fan always on by wiggling the wires, including bad idle and incorrect temp from ECU readings. If I wiggle them in the correct way the issue is gone and I get a correct temp reading and thermo fan working correctly and idle issues disappear.

    With the working PTU I am absolutely amazed at the car being an almost completely different vehicle to drive. There seemed to be a lot of hesitation before including during gear shifts and issues with starting rough/idling rough at start. Looks like I should invest in a series 2 PTU anyway just to ensure it lasts! Might pull apart the other Series 1 to see what happened later on as I found the tech article here about repairing them.

    Since it seems the connector is what's missing from the temp sensor is it worth me putting just a new connector on for now (gives me a little while longer to get some extra money together) and my next goal be the new wiring specialties EFI harness?
     
  6. rob260

    rob260 Moderator Staff Member

    Messages:
    13,250
    Likes Received:
    276
    Trophy Points:
    83
    Location:
    Sydney (North)
    New connector is easy to fit, should be able to grab one from Marcus with the PTU. Sounds like you have found your problems!
     
  7. Hellsheep

    Hellsheep Administrator Staff Member

    Messages:
    244
    Likes Received:
    32
    Trophy Points:
    28
    Cheers mate! I've shot them an e-mail with a list of parts... decided whilst I'm getting a couple things I may as well order a bunch of little bits and pieces I need at the same time. Bye bye money :D
     

Share This Page