ECU Codes 14, 23, and 45

  • Hardway
    Hardway
    Member
    • 86
    #1

    ECU Codes 14, 23, and 45

    After I picked up my car from the paint shop yesterday I saw the check engine light was on. I pulled the codes this morning and it returned the following.

    14 – VSS
    23 – Idle Switch (On/Off Diagnosis)
    45 – Injector Leak

    I disconnected the battery first for about 10 minutes and reconnected. I figured the paint shop drove it around their complex and never got above 3mph so maybe it needed a reset, no luck. Took it for a drive and reset it, no luck. My speedo works so I am not sure why the VSS would be throwing a code. It seems to idle just fine and does not smell rich or anything. I was wondering if there is anything obvious I should investigate before going through all the tedious troubleshooting that the manual shows?
    1988 300zx Turbo GL - 5spd, t-tops, all stock and staying that way.
  • Hardway
    Hardway
    Member
    • 86
    #2
    I have an update. I installed an inline fuel pressure schrader valve over the weekend as well as a new fuel filter and did an injector leak down test. I let the system pressurize to ensure there were no leaks, started the car, and it ran fine. The idle pressure was around 28psi which I thought was rather low for fuel injection. Even as I revved the engine the pressure would climb a little but then come back down. I shut the car off and it pressurized up to 33psi and stayed there for almost 5 minutes then dropping down to 32psi. After another 3-4 minutes it dropped below just 30psi. I released the pressure from the gauge and disconnected. Unless I am missing something I think its safe to say I don't have a leaky injector. Does anyone know what sensor picks up on a leaky injectors?

    I checked my TPS connector and the contacts were a bit green on the plug. I ordered a new one and plan to install it this weekend. My speedometer still works so I don't know what to do about the VSS. I cannot even find a replacement unit so how would I go about replacing my supposed bad one or repairing it? Any guidance is greatly appreciated.
    1988 300zx Turbo GL - 5spd, t-tops, all stock and staying that way.
  • michaelp
    michaelp
    Senior Member
    • 9384
    #3
    Z31 base fuel pressure is 37psi. It should be ~30psi while idling with the FPR vacuum hose hooked up.
    - VG30DET (HE341) 86 300ZX - 1982 280ZX Turbo - Headered NA 1986 300ZX 2+2 - 2000 Xterra -
  • Hardway
    Hardway
    Member
    • 86
    #4
    Good to know. I will double check it later this evening. I appreciate the info!
    1988 300zx Turbo GL - 5spd, t-tops, all stock and staying that way.