Idle timing 15 to 25

Discussion in 'Technical' started by MikeZ32, Mar 26, 2017.

  1. MikeZ32

    MikeZ32 das Über member

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    G'day all, drove the Z today and out of no where started to ping past 3000rpm.

    Have a Conzult LCD in the car and noticed the idle timing is fluctuating between 15 degrees up to 25 degrees.

    AFM readings seem normal and TPS hasn't moved past 0.44V at idle.

    Haven't ruled out a boost leak between the AFM and turbo which may be causing it but the timing is a bit troubling.

    I recall WazTTed and JEDI a while ago saying a faulty neutral switch which can cause big jumps in base timing (in AT to MT converted cars) however my ECU was always a manual ECU which should not affect timing in such a way?

    Anyway, I may just ground the neutral switch, Waz reckon you can give me a breakdown of what needs to be done?

    Could I just ground PIN 44 coming out of the ECU?
     
  2. QLDZDR

    QLDZDR ID=David

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    I am interested to hear how this gets patched because I remember reading that Cam (300zx9)? experienced this jump from 15 to 25 when he installed the SAW kit. I was looking for a method to overcome that.
     
  3. Chrispy

    Chrispy Pretentious Upstart

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    That would have also been a Auto ECU.

    Haven't heard of this issue on a manual ECU. Bit odd...

    Does your car have a clutch switch?
     
  4. MikeZ32

    MikeZ32 das Über member

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    Could also be where my base map was copied from.

    Myself and Sandeep use the same tuner and my base map was basically kept on file by the tuner and he copied it onto my Manual ECU with NISTUNE board.

    Perhaps the base code was copied over which included the auto code for neutral switch timing? I'll need to do more research into that. Maybe Sandeep's ECU was an auto unit.
     
  5. QLDZDR

    QLDZDR ID=David

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    Yes I have an Auspec NA Auto and Auspec Auto ECU and the exact SAW still in the box (which was on Cam's NA auto/manual/auto again)
     
  6. TWIN TERROR

    TWIN TERROR Well-Known Member

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    You maybe onto something. A few years ago I had a new chip written for my e.c.u and had the same symptoms showing on my ecu talk. I have a couple of spare chips in the shed with various tunes so I swapped one in to see what would happen and the idle timing went back to normal. My car appeared to run great with the new tuned chip just the idle timing on ecu talk fluctuated. I even checked the base timing with a timing light at the time and it was fine. I know for sure my original ecu is a manual ecu and I even have a spare manual ecu for rainy days but perhaps the tune could be auto specific ?. I don't seem to feel it is a major concern but would be interesting to see what others tell you.
    Cheers
    Dave
     
  7. 90TTZ

    90TTZ Back From The Dead

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    When you say the timing is fluctuating between 15 and 25 (I'm assuming this is at idle), I would be paying attention to the closed TPS signal (not the voltage). If this is cycling on and off with timing then you need to reset the closed TPS switch reference by disconnecting the grey plug that is wired into the TPS for about 5 seconds.

    Once you have done that and the timing remains stable check the base idle timing with a timing light and ensure it is the same as what Consult is displaying. If it is significantly different to this then it is highly likely the timing belt has jumped a tooth or two.
     
  8. MikeZ32

    MikeZ32 das Über member

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    Interesting, so Dave I'm assuming that even though you saw the timing fluctuations on ECU talk at idle, it did not affect the way the car ran?

    Let me ask you for another favour when you next drive the car, let's say you're cruising around at 2000-3000rpm, what does it show for timing? Mine is showing 30-35 degrees.


    Hi Carl, indeed it is just at idle and would occasionally fall back to 15 from 25 randomly.

    You'll have to school me a bit here on the TPS signal.

    How would would I verify if the TPS signal is fluctuating? Plug in the laptop and find it in the full Conzult software? Or get the multimeter out but where to take the reading?

    I'll give it a boost leak test first tomorrow to eliminate and waste the rest of the day hunt down the the timing issue as well. :rolleyes: Damn Zs, seems to know when it's not getting your full attention and starts throwing a fit.
     
  9. 90TTZ

    90TTZ Back From The Dead

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    In Conzult you can see in the image below in the bottom RHS pane the first variable says CLSD THL/POS. It will have a green arrow next to it when you are at idle but maybe different depending on the version you are using.

    Before attempting to reset make sure your Closed TPS voltage (THRTL POS) is ~.44V). To reset, unplug the grey TPS connector and watch the THRTL POS climb to 5.14V, reconnect and then the CLSD THL/POS should be good.

    [​IMG]

    EDIT: Just read you have Nistune. You can see below there is an indication that says TPS Idle. This will light RED when TPS is closed.

    [​IMG]
     
  10. JEDI-77

    JEDI-77 Jedi Master

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    Pinging

    Mikey, is it pinging under light throttle or when you put the boot in?

    Also, and someone please correct me if i'm wrong, I don't think a boost leak would necessarily cause pinging on a TT. You might be down on power, and you could have higher intake temps due to the turbos having to work harder to maintain boost pressure, which I guess could induce pinging under high loads. But on a turbo car, any boost leak after the MAF would cause a rich condition wouldn't it? The MAF would assume X amount of air entering the engine, and so the required amount of fuel will be delivered. But with some of that air escaping, you would now have excess fuel in the combustion chamber and hence a rich condition.

    A bit different on NA obviously, because the manifold would be under vacuum and hence sucking in extra air after the MAF, so in that case, I can understand how a vacuum leak could cause pinging. But not on a boosted car where you have positive pressure, not vacuum. Having said that, I guess if you have a leak in the intake piping going to the turbo, then that could introduce extra air as that part is under vacuum. But anything after the turbo would be forcing air out, not in. Am I missing something?

    You remember that I had heaps of pinging problems on my old NA, at about 2500-3000rpm under light throttle. I had some theories about why, but none that were popular on this forum. Either way, I could never sort it out. The only way I solved it was by getting a custom tune and taking out a whole heap of timing in those cells where it was pinging.
     
  11. AndyMac

    AndyMac Better than you

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    No, you're right. If it's leaking on the intake side of the turbo after the MAF then yes, if it's big enough it can cause detonation, but anywhere else it would cause a richening of the mixture.

    If it's pinging it's more than likely related to ignition timing than AFR's, and as there's an existing concern regarding timing, even though at idle, it'd be the logical place to start, as whatever is throwing it off may be reflecting through the map.

     
  12. MagicMike

    MagicMike Moderator Staff Member

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    Although I have no data to back it up, I would be looking at the Cas and the cas pins. The more I look around, the more issues people have with unexplained pinging. What controls the timing? The CAS.

    Of course this is secondary to the idle/neutral switch.
     
  13. MikeZ32

    MikeZ32 das Über member

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    Good point Mike, it's usually overlooked for a lot of things. Bloody CAS, it's made by Mitsubishi,
     
  14. MikeZ32

    MikeZ32 das Über member

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    Light throttle or full throttle. Basically as soon as it tries to come onto boost (from around 3000rpm) you get hesitation and can hear the detonation past 3000. Originally I thought it was a leak but then noticed the timing issue.

    If it's a leak after AFM but before the turbo itself it will be sucking in unmetered air that will result in a lean mixture as Andy already said.

    If post turbo and the charge air is escaping the system then it'll be rich.
     
  15. mr_sky

    mr_sky New Member

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    I picked up a new Z not too long ago and had similar symptoms. Started with me trying to work out why it seemed to be running safety boost. Base timing was bouncing around on idle and I could hear some pinging under accel. Found an intake pipe clamp loose on drivers side. Tightened it up, reset the ECU, problem gone. Boost level up and stable timing

    Not sure if applicable here but worth a look.
     
  16. WazTTed

    WazTTed Grease Monkey

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    pm sent !!
     
  17. MikeZ32

    MikeZ32 das Über member

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    Thank you simmo! I'll text you once I get the wire grounded. Will just ground pin 44 directly out from the ECU.
     
    Last edited: Mar 29, 2017
  18. WazTTed

    WazTTed Grease Monkey

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    Ground it in the engine bay its a lot easier :) do you want a pic ?
     
  19. MikeZ32

    MikeZ32 das Über member

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    yes please if you have one.
     
  20. WazTTed

    WazTTed Grease Monkey

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    [​IMG]

    you need to cut the yellow with blue stripe wire, insulate the end closest to the battery , then ground out the wire that leads back into the brown connector !! :) you can check this via datascan /conzult..

    this is a issue with people that have manual converted cars as 99% dont have the correct manual alternator harness as there 250 bucks !!
    [​IMG]
     

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