A Couple Nistune Newbie Questions

  • RMWheeler300zx
    RMWheeler300zx
    Member
    • 40

    A Couple Nistune Newbie Questions

    I'm trying to find the cause of a lean condition in idle causing NOx to be too high for emissions. I have a few questions about the Nistune Logging.

    1: The logging feature is supposed to show what the ecm sees, correct?
    2: Injector Duty cycle seems very low for OE Injectors (1 - 10%)
    3: O2 Sensor shows 0v, is this normal for the Titania sensors, or is the ECM not looking at O2 Sensor at all since Nistune Upgrade, or does it just not show anything for O2 Sensor at all without a WB?
    I can e-mail to log file to anyone who wants it for the information. The drive was a short in town test drive.
  • G-E
    G-E
    Junior Member
    • 6320

    #2
    High nox = hot, timing too retarded, or too lean…
  • RMWheeler300zx
    RMWheeler300zx
    Member
    • 40

    #3
    Timing was dead on (as tested by the smog shop), we already know it's running lean, that's what I'm trying to isolate. If I have no other choice, I will have to just enrich the idle fuel maps, but I would prefer to find out why the ECM is not enriching automatically.
  • jaqattack02
    jaqattack02
    Senior Member
    • 1185

    #4
    Stock injectors?
    Prius… because Pretentious wouldn't fit across the back of the car…

    Cheap, Fast, Reliable - pick any two

    My 1986 Turbo Build
  • G-E
    G-E
    Junior Member
    • 6320

    #5
    Fix your egr ?
  • 88sinZ
    88sinZ
    Senior Member
    • 2019

    #6
    You really need to swap in a wide band 02, and feed signal to the ECU to properly monitor AFR

    Let's elaborate

    1.Logging feature is explicitly by command. you must order the system to log runs. i know the NisTune User manual is shite but read through it again to get baselines.

    2.Have you adjusted your values (K, dwell, MAF adj. for system) for your setup?
    3.I'm going to take a swing and say you still have the OE 02 sensors… junk em, go wide band if you're running NisTune and plane to pull out more power.((((((also, narrowband sensors usually take "in-or-out" readings so if you're seeing 0V the whole time i would imagine some sort of overly rich condition, watch your oil condition and cyl compression before you gas it down or wash em out))))))

    * I don't want a log file, take it to a tuner

    Get it running straight and take it to a reputable tuner. Likely chances are they know nistune on 240's, but its related, get ready to put some more cash up.
  • RMWheeler300zx
    RMWheeler300zx
    Member
    • 40

    #7
    I apologize for the late update, this week has been hell. I decided to try swapping the NTK O2 Sensor I bought (that retarded shop claimed was bad), and remove the Denso Sensor they put in, when I found something that made me less than happy. My O2 sensor harness was left sitting on my exhaust manifold crossover and the two connectors are fused together! I can't even separate them to check the wiring. Anyone know where I can get an O2 Sensor pigtail for the 89 Z31. I'm wondering if the pins in the connectors are destroyed as I can see some remains of the Weatherpack seal amongst the melted plastic.
  • jaqattack02
    jaqattack02
    Senior Member
    • 1185

    #8
    Just unplug it and leave it unplugged. Not really needed anyway.
    Prius… because Pretentious wouldn't fit across the back of the car…

    Cheap, Fast, Reliable - pick any two

    My 1986 Turbo Build
  • RMWheeler300zx
    RMWheeler300zx
    Member
    • 40

    #9
    I'd like to, but here in the land of emission Naziism they won't pass the car if the O2 sensor is disconnected. I ended up cutting the melted connectors off and splicing the wiring directly, still no voltage signal from O2 Sensor, so I'm going to ignore it and try tuning it up without it. I'm just looking at making it more rich around 15mph to hopefully get the NOx within spec to get my tags, then I will try to find a shop that's familiar with Nistune to do a full dyno tuning job. Anyone know of someone in San Diego County that knows Nistune?

    Injectors are stock spec, new replacements though. The A/F Ratio during the 15mph segment of the test was more around 15.7:1 if I saw the screen right on the emissions program. Since then I've put the factory air box back on, reconnected the FTS (which came off while driving around warming new cat up), and have finally got my license for NISTUNE.

    My knock sensor isn't connected due to damaged wiring, but I would imagine the ECM would just see it as no knocking (Knock sensor generates signal from vibrations, no signal no knock?).
  • G-E
    G-E
    Junior Member
    • 6320

    #10
    With nistune you can disable the o2 feedback anyway, they recommend it for tuning… the wideband is far more sensitive and you don't want the ecu compensating while you're trying to find ideal values
  • G-E
    G-E
    Junior Member
    • 6320

    #11
    RMWheeler300zx wrote: I'm just looking at making it more rich around 15mph to hopefully get the NOx within spec to get my tagsFixeth thine EGR man

    RMWheeler300zx wrote:
    My knock sensor isn't connected due to damaged wiring, but I would imagine the ECM would just see it as no knocking (Knock sensor generates signal from vibrations, no signal no knock?).
    The sensor always makes noise, the ecu then decides if that noise is normal or erratic and strong enough amplitude to consider it a knock
  • RMWheeler300zx
    RMWheeler300zx
    Member
    • 40

    #12
    The car will be getting some more proper repairs later, but being unemployed, I'm just trying to get the smog and registration done. Electrically the EGR is functioning; I will see what I can diagnose with it mechanically tomorrow. I will be going crazy trying to keep my mind occupied the last half of this week anyways do to some more serious issues I'm having.