S30Grit

280Z Requires Starting Fluid for Cold Starts

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    yep, I see that. Oh well...

    If it was me I would have a spark indicator on it, a fuel pressure gauge on it, a stethoscope on the injectors, and have someone else cranking while I watched for everything else.

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    3 hours ago, Captain Obvious said:

    So, I got a question.... When you say it won't start without a spray of starter fluid, how long are you cranking it for before saying it "won't start"? Reason I ask is that I removed my cold start valve completely and it definitely takes longer to start without it than it did before I took it off. Maybe five seconds of cranking? I'm wondering if you just are giving up too soon.

    What happens if you crank the engine for fifteen seconds straight? Sounds like a short amount of cranking, but with your hand on the key, it doesn't feel like a short time.

    I've definitely tried some starts over 5 seconds (and yes, my hand gets tired with just that due to the small key!).  15+ seconds hasn't been tried, but is that extra strain on the starter motor? I've always used starters sparingly (i.e. <5 seconds) my whole life due to concern of heat/wear on them for long starts, but that may be a completely unfounded concern!

    I've also tried some ~5 second starts, waiting 10+ seconds, then repeating. But I'll try some other approaches as well.

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    1 hour ago, Dave WM said:

    yep, I see that. Oh well...

    If it was me I would have a spark indicator on it, a fuel pressure gauge on it, a stethoscope on the injectors, and have someone else cranking while I watched for everything else.

    This does seem ideal.  Right now, my main focus will probably be tracking down the injector signal pulse issue since I know they aren't firing (and checking CSV).  After that, I'll be re-confirming those previous things like fuel pressure and strong spark, etc..

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    what are the engine temps when you are having problems with starting please, maybe you covered it already.

    I just tested my spare engine on the test stand, with the CSV disconnected and the fuel pressure at zero, it started almost instantly. this was at 82f which should not need the CSV and even connected it prob would not have fired since the temp was too high for the thermotime to activate.

     

    Edited by Dave WM

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    6 hours ago, Dave WM said:

    what are the engine temps when you are having problems with starting please, maybe you covered it already.

    Dave WM - Ambient temperature has been around the 80's previously when trying to start, so I'd guess coolant/engine temp wouldn't be too much lower than that, maybe 70F if I had to guess. 

    Thanks for the video.  Definitely good to know that it should crank right up without issue in warm weather regardless of CSV!  I'll check mine just out of curiosity

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    I have a new thought.  Maybe the AFM blade is sticking shut during the low air flow of starting.  That would lower the injector open time, delivering less fuel.  Maybe pop the cover off the AFM and watch it, or prop it open.

    Also possible that you have a vacuum leak that also allows air to bypass the AFM.

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    This is one vacuum hose that isn't OEM and doesn't seem to be sealing properly.  Might try clamping it before replacing to see if that helps.  As for the AFM, not sure how that guy works yet.  But I think the FSM has some basics checks that I can do on it.

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    Smoke test is a good way to find vacuum leaks. plug up the throttle body with a stryofoam cup, get a cheat stogie, I like to use a clear tube connected at the brake booster fitting, puff on the stogie and blow smoke  in the tube. You should feel resistance, but as it fills with smoke look for leaks. I recently found a few using the method, one was a missing injector o ring and the other was a split on the valve cover vent pipe.

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    2 hours ago, S30Grit said:

    Dave WM - Ambient temperature has been around the 80's previously when trying to start, so I'd guess coolant/engine temp wouldn't be too much lower than that, maybe 70F if I had to guess. 

    Thanks for the video.  Definitely good to know that it should crank right up without issue in warm weather regardless of CSV!  I'll check mine just out of curiosity

    Well if its in the 80's or upper 70's its def not a CSV issue. Forcing it to fire at higher temps may help the starting but that's really just covering something else that is wrong.

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    31 minutes ago, S30Grit said:

    This is one vacuum hose that isn't OEM and doesn't seem to be sealing properly.  Might try clamping it before replacing to see if that helps.  As for the AFM, not sure how that guy works yet.  But I think the FSM has some basics checks that I can do on it.

    Take the black cover off of the side of the AFM.  It is just a press fit with some light sealant to hold it in place.  There is a damper weight that moves with the AFM vane.  If you move the weight the vane will move, and vice-versa.  It should start moving as soon as the engine turns over.

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    21 hours ago, S30Grit said:

    I've definitely tried some starts over 5 seconds.  15+ seconds hasn't been tried, but is that extra strain on the starter motor?

    Yes, I would agree that 15+ seconds of continuous cranking is disconcerting and not something that you would want to be necessary. But I'm trying to make sure I have an accurate handle on the problem.

    You said that the engine refuses to start on it's own when it's cold, but with a quick spray of starting fluid it starts up and RUNS instantly.

    I'm wondering if the problem is more accurately described as "when the engine is cold, it takes a lot of continuous cranking (like fifteen seconds) to get it to light off. But once it does start, it runs fine".

    I would apply a different approach to troubleshoot those two different scenarios.

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    Video of the problem is always good. how about a video of your cold start procedure with the starting fluid. Be sure to include things like engine temps etc..

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    Another guess.  I went back to the first post but can't be sure.  How old is the fuel in the tank?  Old fuel will often lost volatility.  Sometimes it will last for years, sometimes it goes bad in months.  

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    3 hours ago, Captain Obvious said:

    Yes, I would agree that 15+ seconds of continuous cranking is disconcerting and not something that you would want to be necessary. But I'm trying to make sure I have an accurate handle on the problem.

    Sure thing, I'll give it a go.  I don't have easy access to a battery tender where I'm at, so for this test I may also run jumper cables to the car.  Testing two variables at once, but still useful data I think.

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    44 minutes ago, Zed Head said:

    Another guess.  I went back to the first post but can't be sure.  How old is the fuel in the tank?  Old fuel will often lost volatility.  Sometimes it will last for years, sometimes it goes bad in months.  

    That was definitely a problem when I first got the car, but the mechanic drained a good amount of fuel and put in fresh fuel about 2-3 weeks ago.

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    8 hours ago, S30Grit said:

    Sure thing, I'll give it a go.  I don't have easy access to a battery tender where I'm at, so for this test I may also run jumper cables to the car.

    Yeah, I wouldn't want to have to crank twenty seconds every day, but just once to see if it will eventually start without the ether could potentially be a helpful data point.

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    Had a few hours to work on it today, spent most of it putting the new injectors in.  I came to a few realizations:

    1) (Rant Warning). I learned to NOT to trust parts willy-nilly from zcardepot.com.  I purchased the injector holders on their site, https://zcardepot.com/products/fuel-injector-base-holder-trigger-280z-280zx-75-83?_pos=5&_sid=a8aee91be&_ss=r# because one of mine was cracked.  I figured if I ordered them from somewhere, surely a Z parts specialty store would sell something that fit.  NOPE.  My two-piece OEM holders fit perfectly and they screw right in.  These cheap parts from "Standard Motor Products" (which isn't named on the zcardepot product page) do not align with the screw holes on the intake manifold.  It's close to aligning, but too far off to even get a thread in.  Of course I had no drill/bits with me to bore them out, so I used some sand paper and a screw to 'bore' one of them out enough to barely fit. I cracked the other messing around with it.  Frustrating to say the least. +1 for the OEM purchasers... Makes me scared about buying other parts for the Z.

    2) CSV was definitely gunked up. Cleaned, soaked, and clicked the solenoid with some injector cleaner.  It sprays now when given 12v w/fuel pressure.  Likely too warm today for the thermotine to trigger it anyway (75F).  And as discussed previously, CSV most likely isn't cause of my starting issues.

    3) Battery voltage while car was off is around 12.2V.  When cranking, it drops to around 10.25V.  Battery isn't fully charged from all the cranking it's done lately, but these numbers still seem normal.  https://tontio.com/auto-guides/car-battery/car-battery-voltage/

    4) It was getting dark and probably around 60-65F outside when I tried to start it for the first time today.  I couldn't even get it to start on starting fluid (only sputtered).  This is probably the coldest outside temp I've tried to start it (unsure if related).  Also it maybe has some air in the fuel lines that needs to clear out, and since my injectors aren't firing (#5 below), not sure the air was getting pushed out.

    5) To sanity check the mechanics work, I checked one of the injector wiring harnesses.  While cranking, an LED on the harness did NOT turn on.  While messing with the key in the ignition, I saw the LED flicker 1 time, not even a "pulse" but a flicker.  I'm still determined this is the cause.  Something in the ignition assembly (even tho it's new) or other EFI wiring must not be connected/grounded right. 

    I found it bizarre with the key in the ON position, and the motor not started: both pins on the injector harness had +12 volts.  Either pin would light up a test light with the other end grounded.  One pin is supposed to have +12v at all times, but I thought the other pin should be floating, waiting to ground pulse to complete the circuit.  Tomorrow I'll be doing FSM tests related to this circuit tomorrow.

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    The situation where you're getting +12 on both sides of the injectors is normal. It only takes a small amount of current to light up the test light and you'll pull that small amount through the injector on the floating side. It's not enough current to click the injector, but it'll pull enough to light the test light,

    In fact, you'll see that same situation even if you pull the connector off the injector completely. You'll pull current through one of the other injectors. Like this:
    injectormeasure1.jpg

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    On 10/18/2019 at 8:14 PM, Zed Head said:

    Take the black cover off of the side of the AFM.  It is just a press fit with some light sealant to hold it in place.  There is a damper weight that moves with the AFM vane.  If you move the weight the vane will move, and vice-versa.  It should start moving as soon as the engine turns over.

    I still think that this is worth doing.  If the vane is stuck you'll get less fuel.  It's not uncommon, I think that confirming the vane isn't stuck is one of the checks in the FSM.

    As far as the starting fluid non-start is concerned, where are you squirting the fluid?  You should squirt it in to the manifold after the throttle blade for best effect.

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    A fully charged battery is 12.6v, so you need to get it charged up. It also drops a lot when cranking, how old is the battery. Probably not a direct cause but EFI and ignition systems don't like low voltage. Things get wonky when the voltage drops too much

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    Another guess and one that happened to me except that it happened when things got hot.  The EFI relay coil would get an open circuit and not actuate the relay during starting.  Just crank, crank, no start.  You could jump the EFI relay pins as a test.  

    One more - you say that you're not getting the injector test lights flashing during starting.  This could also be caused by loss of injector power.  Put a meter on an injector plug and see if you lose power during starting.

    The best way to solve these EFI problems is with a detailed list of tests and knocking them off one by one.

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    12 hours ago, Captain Obvious said:

    The situation where you're getting +12 on both sides of the injectors is normal.

    Gotcha, good to know, makes sense as it was a lower power LED bulb.

     

    10 hours ago, Zed Head said:

    I still think that this is worth doing.  If the vane is stuck you'll get less fuel.  It's not uncommon, I think that confirming the vane isn't stuck is one of the checks in the FSM.

    As far as the starting fluid non-start is concerned, where are you squirting the fluid?  You should squirt it in to the manifold after the throttle blade for best effect.

    A few things on the AFM.  Relatively sure the AFM is actually a new unit (more parts someone threw at it).  The vane opens with ease by hand.  I'm working on my own and can't watch it during startup.  But I'm actually spraying the starter fluid in a tube connected to the AFM, and since I'm getting a sputter at least, I think I can assume the vane is opening at least some.

     

    10 hours ago, Patcon said:

    A fully charged battery is 12.6v, so you need to get it charged up. It also drops a lot when cranking, how old is the battery. Probably not a direct cause but EFI and ignition systems don't like low voltage. Things get wonky when the voltage drops too much

    Battery is 10 months old, spent most of it's life on a battery tender in a garage.  I tried the jumper cable start (my working car has a solid 12.8V or so) and didn't make a difference in terms of starting. I also tried starting for 15 seconds non-stop in the jumper cable config and no dice.

     

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    10 hours ago, Zed Head said:

    One more - you say that you're not getting the injector test lights flashing during starting.  This could also be caused by loss of injector power.  Put a meter on an injector plug and see if you lose power during starting.

    Grit, I'm not really suggesting things that you should do on a whim, I'm suggesting things that I would do if I had your problem.  I'd use a mirror to see the AFM.

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    image.png

    This the first group of tests some of you may recognize from the FSM.  At the beginning of today, I flunked this thing BAD.  Spent a lot of time tracing down grounds/wiring issues and made some improvements. Results of before and after are:

    • 1-1 (throttle valve)
      • Before: Fail, 2-3Mohm.  
      • After: Pass
    • 1-2 (throttle valve open)
      • Before: Fail, open circuit
      • After: Pass
    • 1-3 (AFM)
      • Before: 180 ohm, 180 ohm, 100 ohm
      • After: Same
    • 1-4 (air temp sensor)
      • Before: 1.7 Kohm  (weird temp reading)
      • After: Pass, 2.3 Kohm
    • 1-5 (water temp sensor)
      • Before: Fail, 8 Mohm
      • After: Pass, 2.3 Kohm
    • 1-6 (air regulator)
      • Before: Fail, 27 Mohm
      • After: 61 ohm (?)
    • 1-7: Pass
    • 1-8: Pass
    • 1-9: Pass
    • 2-1: Pass
    • 2-2: Pass
    • 2-3: Pass

    Where a "Pass" is a resistance of just a few ohms.  Even after "fixing" these wiring issues, still won't start.  Injectors still not pulsing while cranking.  I didn't have time to focus strictly on EFI wiring, but cleaned as many grounds as I could get my hands on.  Maybe drop resistors aren't supporting enough current, or issue at relay pins like Zed Head mentioned...

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    Well the biggie is the water temp sensor, at 8meg it would run big rich, the 2.3k must have been a cold engine (not run in a while, long enough to cool down). the air regulator must be the heater resistance. the water temp sensor should have made a huge diff.

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