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Stalling Engine Trivia

Discussion in 'Diagnosis/Help' started by Bers, Apr 11, 2015.

  1. Bers

    Bers Active Member

    Hello, dear internet

    I recently has a couple of engine stalls/misfires (for the last 150km or so).
    The car did not show any of these signs for the last 14 years :).
    This is new, so to start with, it otherwise runs fine.

    - Sharp, sudden misfire on ALL cylinders, for a split second.
    - On the highway, when it happens, car will keep going (short power interruption when driving, but it comes back).
    - If the interruption happens while idling, engine will die instantly.
    - When it stalls at idle, most of the time it will not restart for a couple of minutes (2-4 min avg interruption).
    - When I try to restart it, engine will turn as usual, but it will not fire at all (for as long as the interruption lasts).
    - When it won't start, engine turns but RPM signal stays flat on the tach.
    - When interruption is felt while cruising, RPM signal is momentarily lost (even if I keep moving forward with gear engaged and engine turning).

    Investigated items:
    - Power to ECU is good. Verified with a voltmeter attached to E01 and +B (even when stalled, power is still delivered to ECU).
    - ECU is clean (opened up, no visible damage, no cracked solderings).
    - Battery terminals are OK. I even added an additional new ground wire to the body, but it did not change anything.
    - No loose relay beside the battery (EFI main, etc).
    - I tried provoking the interruption when the car seems to run fine, by pressing/moving ECU/coil/ignitor/distributor connections, but nothing I did seems to provoke the problem, whatever I do it just seems to die on it's own after a while.

    Following these symptoms, I applied the following reasoning:
    1) Since the problem is correlated with RPM signal loss, I rule out fuel delivery issues. Prove me wrong... but can an engine run without RPM signal?
    2) Since playing with ECU/coil/ignitor/distributor/harness connectors does NOT make the engine stall, I *think* the problem is WITHIN an ignition-related component.
    3) Given the comb meter RPM signal is lost when this happens, my suspicion is drawn around the igniter, the ECU and the ignition coil.

    I think my biggest clue is the loss of RPM signal when engine dies.
    From that point I have no clue, however, how to tell which is bad.

    Has anybody a clear mind to help me refine my thought process and pin-point this issue?
    What other investigation can I carry to confirm/infirm the problem lies either in igniter/ECU/coil unit?

  2. ST165-2765

    ST165-2765 Well-Known Member Donated!

    I think your correct in thinking its not a fuel problem

    So...................lets look at the BGB and find out where your rpm signal is coming from


    Your rpm signal is coming from the igniter and thats a good place to start your investigation.
    Your igniter is bolted to the firewall and gets its ground from that connection. I would unbolt it and clean up the 2 contacting surfaces and use some dielectric grease

    I had a similar problem for about a year car would run fine and suddenly die and I eventually traced it to a faulty engine wiring harness. When it would die I would go in and look around and replace igniters and distributors and coils and still the problem came back and I decided that the only thing I had done every time was move the engine wiring harness around while I was replacing the various components so the next time it died I just tried moving the engine wiring harness around and found that by wiggling the harness in the area of the distributor I could get the car to start again

    So hopefully your problem is as easy as an igniter ground issue....if not then I'll see what the tests are for IGT & IGF and all the other signal are
  3. toyotawes

    toyotawes Active Member

    RPM signal will also disappear if the coil/igniter is simply losing power. I had a car with a slowly worsening ignition switch which when bumped the wrong way would kill the car as though the key had been shut off. You may have an intermittent bad connection somewhere along the path from the battery to your coil.
  4. Bers

    Bers Active Member

    Very interesting. Thank you very much for this, it would also make a lot of sense given my symptoms.
    My suspect #1 still is the igniter (ICM Module), but I will also keep my eyes open for this and possibly do some more testing before ordering a 300$ ICM.

    For now, I have checked my secondary ignition coil resistance, which is 75K ohm (above normal).
    I will probably change it, although I don't think this is my main problem (when I disconnect high voltage wire from coil to distributor, I still have an RPM signal, therefore it seems something else also failed).

    My current theory is the igniter went bad, which might have damaged the coil (too much dwell time, maybe?).

    Not sure about anything. Could still be as simple as a bad connection, although I can't find any evidence of it (wiggling connections and harness doesn't change anything, good or bad).
  5. toyotawes

    toyotawes Active Member

    Do you have a factory manual? I know there are instructions for testing the igniter in the manual I have for my 85, havent looked at the bgb for my 87 to see if similar instructions are there...

    Do you know if the igniter is the same on the n/a 3sge? I believe I have a good spare kicking around somewhere.
  6. Bers

    Bers Active Member

    Thanks for taking the time to respond.
    I did buy dielectric grease and made sure the ICM was properly grounded.
    It did not fix my issue, however. It seems like it's getting worse over time :(.
    I checked my coil resistance, and it was somewhat off (75k ohm). This is about 7 times as high as it should.
    However, my symptoms are much closer to a failed igniter modules, such as described in the link below:
    e.g. http://www.tegger.com/hondafaq/igniter-operation/badigniter.html
  7. Bers

    Bers Active Member

    I do have the Big Green Book from Toyota.
    I tested the coil, but I am not yet done with the igniter testing procedure.
    The thing I am afraid of is whether or not it has to be in a "stalled state" for me to carry any conclusive investigation.

    I will probably end up bringing test wires from engine compartment to the cabin with a test light/voltmeter, for diagnostic while it goes bad.
  8. Bers

    Bers Active Member

    About the igniter, they are different part numbers :
    8962020221 (GTS) vs 8962120030 (Turbo)

    Given I am unsure about actual difference, I would avoid using the wrong part.
    Thanks anyway, so many parts are interchangeable on ST162/ST165, it was a good guess.

  9. Bers

    Bers Active Member

    I finally had some time to pursue investigation.
    It was a wiring/harness problem, pretty much like everyone else with similar symptoms.

    One of the wires on the coil connector looked like crap, was badly bent/corroded and snapped off while I was looking around. I Replaced it and the car runs fine since.
    All other wires around going to the fuse box, AFM, resistors & diagnostic connector looked clean & solid, so I'm happy this is solved and confident it should not be a problem again.

    Thanks very much for the help, I appreciate.
  10. toyotawes

    toyotawes Active Member

    Glad to hear you got it taken care of. Intermittent problems are the worst!

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