Presumed no spark ignition scope pattern

quickstudy

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Posted this on Supra Forums as well. I'm struggling to understand what is keeping my car from starting. It was running poorly with Emanage Ultimate after a head gasket replacement, and i found my valve timing was off, first dumb mistake. I fixed that and triple checked the cps alignment, cranked it, and it sputtered with a few chugs of ignition, but then the battery was dead. I hooked up a shop charger, but spaced and reversed the polarity. Second dumb move. Sigh. This blew a main fuse, but i dont see any other blown fuses.

now it cranks but won't start. No sputter of ignition. Two inductive timing lights both fail to trigger off the plug wire. I put brand new coils on and rigged up a plug tester and I was surprised that all the coils fire random test plugs outside of the engine, though the sparks look faint. tried two ignitors, neither working.

the Ig- signal looks abnormal, hoping for help understanding what it is showing me.



red is IgT going into EMU, purple is IgT to to he ignitor. blue is IgF. Orange and green are IgA and IgB.
I have good cps signals, not shown.

I haven't tested the injector circuits yet. Is the ignition system ok? photo_1588543741464.jpg
 

quickstudy

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ok, I'll report back. but with 650cc injectors it has never started without the EMU, but if i get my timing gun to fire, or a sputter of ignition, that would be interesting.
 

figgie

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ok, I'll report back. but with 650cc injectors it has never started without the EMU, but if i get my timing gun to fire, or a sputter of ignition, that would be interesting.
You need to disconnect the injectors. You are testing for ignition. No need to fuel dump into the chambers when it is not needed.
 

quickstudy

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You need to disconnect the injectors. You are testing for ignition. No need to fuel dump into the chambers when it is not needed.
Thank you for replying, good thought. I cut fuel with emanage when testing and can verify injector open times are negligible. when i did the scope tracing i turned fuel back on for a few seconds, since fuel affects spark lines. it didnt look different to my eye with injectors off or on, fwiw.
 

figgie

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the reason to disconnect fuel is that you do not want any fuel during the cranking test. You are not starting the car. You need that emanage out of the way to make sure OEM stuff is working (and more than likely it is short of the TCCS getting fried).

the stock igntion system is very simple. The ignitor controls timing. if it is not working, it is not getting the proper signals from the TCCS. Get that emanage out of there.

On a side note, 650cc/min injectors on an emanage, i am going to say this out loud. How have you not grenaded that motor is beyond me.
 

3p141592654

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I would suspect that the reverse polarity has blown a fuse or fusible link that you have not caught. Your ignition waveform look ok to me. Surely enough to validate that the ECU is alive and that the CPS signals are being read and the ECU is interpreting them correctly.

I would look at IG1 and IG2 from the ignition switch. Verify both are providing 12 V when the ignition switch is on. IG2 can be verified by confirming 12V at the injector resistor pack and +B at the ignitor. IG1 should be good given the ECU appears to be working. You can see here there are a lot of fuses and links that can be fried. At a minimum confirm EFI, Engine, and ignition fuses are good.

 

quickstudy

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I would suspect that the reverse polarity has blown a fuse or fusible link that you have not caught. Your ignition ...
thanks Jon, I was hoping you might weigh in. Scope patterns are not my thing. Figgie's suggestions are also good. I actually did check all fuses, but i will give it another go round, and try without the Emanage. I'm not sure what the concern is with damaging the motor. my lexus afm is normally paired with 550 injectors, so cutting fuel a bit doesn't seem extreme or dangerous. It ran well before i found a small head gasket leak that looked like damage from installation. I've got egt monitoring, wideband, and i will get a professional tune once its running. I thought EMU was a reasonably common setup.
 

quickstudy

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the reason to disconnect fuel is that you do not want any fuel during the cranking test. You are not starting the car. You need that emanage out of the way to make sure OEM stuff is working (and more than likely it is short of the TCCS getting fried).

the stock igntion system is very simple. The ignitor controls timing. if it is not working, it is not getting the proper signals from the TCCS. Get that emanage out of there.

On a side note, 650cc/min injectors on an emanage, i am going to say this out loud. How have you not grenaded that motor is beyond me.
good point. i will cut fuel when bypassing EMU. My motor is built and should be able to handle the power. Im confused about your side note.
 

figgie

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good point. i will cut fuel when bypassing EMU. My motor is built and should be able to handle the power. Im confused about your side note.
To run 660 you would have to scale afm frequency which means even more aggressive ignition timing than oem.

There is a thread by 3p on the decompile of the tccs and in it, the direct relation of afm and ignition timing.
 

quickstudy

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To run 660 you would have to scale afm frequency which means even more aggressive ignition timing than oem.

There is a thread by 3p on the decompile of the tccs and in it, the direct relation of afm and ignition timing.
i am aware, i worked a little on the decompile and have the code. with emu i can adjust timing as well as scale afm frequency. i am starting with lexus afm and opening bypass air a little so afm scaling roughly matches the injectors, then i will build my maps from there. equivalent would be to scale down the a stock afm frequency and adjust fuel to adjust for the falsely low air flow reading. My goal is to preserve as much of the stock engine look, character and technology of the car while adding power. Right now i just want a basic start. too late to do much tonight. i did verify that i have ig1 and Ig2 voltage. will proceed with other TCCS checks from TEWD next weekend as we are due for cold weather.
 

3p141592654

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The fact that things changed after the reverse polarity event is a red flag that something is different. Usually the alternator circuit fries and the main fusible link blows. I am wondering if the B+ to the coils is bad. Did you scope B+ during your tests? You could try temporarily jumping that with a wire to the battery.

What is the yellow trace? It cannot be the secondary waveform since there are 3 coils. , can you explain how that was measured? I would try to do a classic secondary measurement of one coil if you have the capacitive probe. Or, scope one of the 3 Igx wires from igniter to coils. Based on IGf and the big spike in the yellow trace it sure looks like the coils are firing which makes the lack of an actual spark very strange unless B+ is weak.
 
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quickstudy

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Thanks, it is puzzing. The yellow trace is Ig- from the test connector. I don't know how it is generated but it's what I usually use and it seems to be a composite of all cylinders.
I definitely have B+, just checked again. I have no visible spark. i rigged 2 spare plugs in a grounded carrier and hooked them to the first coil pack for plugs 1 and 6. at the primary connector I have over 12 V. previously I had a weak spark, but I tested in the daytime now rather than night, so maybe that's why i saw nothing. I also fixed the plug gaps, which were too small.

I don't have a way to test primaries directly.

The ignitor has JJ's ground mod so it's well grounded.
 
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quickstudy

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Update: I completed my tests. eliminated emanage. did voltage tests for sock ecu from TSRM. all relevant tests were normal ( excluding tests requiring the car to be running). The original ignitor only shows firing on Ig- lead every 6th firing of IgT. I know, every third would make more sense. IgT, IgF, IgA and IgB all look normal. IgF mirrors Ig-. The total peak voltage on Ig- looks like 2 v when it fires and there is no visible spark.

A spare ignitor fires every time with IgT, plugs visibly spark. Im not sure why i see no spark line, but I can think of a few reasons.


When i tested the original ignitor per TSRM, it appeared to work inconsistently, so that matches my test results.

Im going to consider this question resolved.



thanks for the help :)
 
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quickstudy

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It's running! It did need the ignitor, but the other problem was fouled plugs from all the start attempts, as Figgie suggested. I went back to new stock copper plugs until i have everything working. I was using iridium one grade colder.

New plugs and new Igniter and it is starting without EMU.

Thanks again for the help.
 

quickstudy

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So it runs with a new igniter?
It only worked with both new igniter and with new plugs. The trace i posted was with a spare igniter, but the plugs, though new iridiums, had become fouled enough with testing setting up EMU that once i got a good igniter in it still wouldn't start. I was still thinking igniter, but finally got smart and changed the plugs too and it started right up. So the scope pattern was showing primary coil firing with plugs so fouled they weren't sparking at all. The iridiums didnt look that bad and were gapped to 32, but they were bad enough.

But clearly my first igniter was bad, because even the primary coil was only firing occasionally. In one sample it fired once for 6 IgT pulses. Changing nothing else, the spare igniter fired the primaries once for each IgT pulse. So I think reversing polarity on the battery charger and attempting to start the engine with fouled plugs is one of the few ways you can ruin your igniter. Would the fouled plugs add to the strain/heat on the igniter power transisters?
 

quickstudy

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I hate to admit it, but the igniters are fine. it was just plugs fouled. now that i have it running well i went back and checked. Seems like i had trouble getting my pc oscilloscope to trigger correctly on certain time scales. I don't want to leave a thread with incorrect info.