Has anyone had trouble using a timing light with FAB9 coils? - Miata Turbo Forum - Boost cars, acquire cats.

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Old 05-18-2015, 12:36 PM   #1
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Default Has anyone had trouble using a timing light with FAB9 coils?

I finally got the car to run (again with Scotts help), and fixed all lumpy and idle woes due to a pesky vacuum leak. However, I am unable to verify base timing offset angle as my timing light doesn't function when clipped around cylinder 1 of the fab9 plug harness.

I thought my timing light was busted, but I checked it on an old Honda accord and it works perfectly.

Has anyone had any issues with this? Wondering if my timing light is not sensitive enough to read induction from these wires?
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Old 05-18-2015, 01:27 PM   #2
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Try clipping around a different cylinders harness?
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Old 05-18-2015, 01:37 PM   #3
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Take the COP out, stick an old spark plug in it, then grab one of your old plug wires. Hook the coil end of the old plug wire into the electrode on the old plug so that it makes contact with the center, and then plug it into the real spark plug in the head, then use the timing light on the old plug wire. It's a hack, but it works pretty well.

--Ian
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Old 05-18-2015, 01:56 PM   #4
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shouldnt need to do that, but if there's any insulation on the wires, you might need to pull that off to get a good reading.

is this the update module for the fab9 coils? they dont play well with real ECUs and you/we/i need to alter the msq for them.
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Old 05-18-2015, 02:47 PM   #5
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Quote:
Originally Posted by codrus View Post
Take the COP out, stick an old spark plug in it, then grab one of your old plug wires. Hook the coil end of the old plug wire into the electrode on the old plug so that it makes contact with the center, and then plug it into the real spark plug in the head, then use the timing light on the old plug wire. It's a hack, but it works pretty well.

--Ian
I just stuck a plug wire between the coil and spark plug and got the signal off that.

Brain, what is the latest adjustments needed for the fab9 cops to play nicer with MS? I had the original ignition module that gave me problems, switched to his new one and its been better but still seem to get some Breakup under certain high load/kpa conditions. Gapping plugs tighter helped a little as well.
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Old 05-18-2015, 02:57 PM   #6
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I'm unsure if this is the old or new version. The kit was shipped in October '14. I don't have any original plug wires to do the hack, this motor was replaced/rebuilt of a bp4w that had Toyota COPS. I switched up since I'm using 18psi's old VVT head and the whole mounting compatibility thing. Maybe with luck I can just harvest one off the accord to see if it'll fit

I wish I could find some oem coils locally. I really want to see this done.


If it matters, this was what FAB recommended:
Quote:
Dwell we usually recommend 3.2ms and .7ms spark duration
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Old 05-18-2015, 03:07 PM   #7
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The newer model has HENST on it, and it also has the aluminum backing plate sticking out of the sides to mount the screws thru.

Also, I think I was able to get a decent signal from the green wire near the connector on the module. Try clamping around that.
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Old 05-18-2015, 06:41 PM   #8
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Quote:
Originally Posted by Mech5700 View Post
I just stuck a plug wire between the coil and spark plug and got the signal off that.

Brain, what is the latest adjustments needed for the fab9 cops to play nicer with MS? I had the original ignition module that gave me problems, switched to his new one and its been better but still seem to get some Breakup under certain high load/kpa conditions. Gapping plugs tighter helped a little as well.
Yeah, the metal on the plug wire didn't reach deep enough into my Toyota COPs to make contact, thus the old plug as an extender.

Originally I tried doing it by putting the timing light clamp around the individual wires in the COP harness. I found that on the ground and signal wires it didn't pick up a signal, while on the power wire it did but it was telling me the *start* of the charging period rather than the spark firing, so the result was off by the dwell period.

The low-voltage wire approach may work, it depends on the details of your timing light and the coils in question. The "use a plug wire" method is simple, unambiguous, and should work with anything. Just don't touch it.

--Ian
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Old 05-19-2015, 12:50 PM   #9
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Quote:
Originally Posted by Mech5700 View Post
I just stuck a plug wire between the coil and spark plug and got the signal off that.

When I used to be a RB Nissan guy, this was the only way I could get a good read. They have a ground loop in the back, but never got that to work right.
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Old 05-19-2015, 04:00 PM   #10
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I thought I was having issues and it wasn't reading properly....then i realized I had my timing light clamp on backwards...installed the other way and she works like a charm on fab9 and any other ignition system.
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Old 05-19-2015, 07:46 PM   #11
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Clipping it onto the Green wire near the ignition module worked, but I had to set the trigger offset angle to nearly 24.1.

The idle is still a bit jumpy so I'm unsure if I should trust this, and I'm a bit reluctant to keep it idling/heat cycling before it's maiden voyage.
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Old 05-19-2015, 07:56 PM   #12
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nope. should be in the 4.8-7 range, nowhere near 24.1
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Old 05-19-2015, 08:48 PM   #13
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I double checked the mechanical timing and it still seems correct, I'm stumped. It won't hold idle
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Old 05-19-2015, 09:41 PM   #14
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Your harmonic balancer may be starting to separate. The outer ring may have shifted-falsifying the location of the timing marks. I had an issue with this, requiring huge amounts of offset to even get close.

https://www.miataturbo.net/megasquir...4/#post1167352
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Old 05-20-2015, 07:30 AM   #15
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That would be most unfortunate; it's a SuperMiata damper. The trigger wheel can only be installed one way, correct? I'm confused. Will check again, but timing marks all hit.
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Old 05-20-2015, 08:56 AM   #16
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Ah ok, I was assuming it was OEM.

As far as the wheel, I am unsure. I haven't had my hands on one yet.
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Old 05-20-2015, 09:08 AM   #17
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In static form, the TDC mark on the crank sprocket sits correctly on the arrow of the oil pump and the tick mark on the pully hits the T appropriately on the plastic cover. Could it just be one of those anomalies of swapping VVT into NA chassis?

I guess the real dilemma is, do I trust known values of 5-7 trigger offset angle, or do I trust what the light and what megasquirt is telling me is working?
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Old 05-20-2015, 10:05 AM   #18
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Did you try a wire from the accord?
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Old 05-20-2015, 10:37 AM   #19
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I tried the wire from the accord, but the pencil tip of the FAB9 cops didn't have a spring or anything to make contact with the terminal within the boot of the plug wire. It was a tiny hole in which the sparkplug head would slip into.
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Old 05-20-2015, 10:53 AM   #20
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Doesn't necessarily need to make contact, it should be able to jump the gap and give you a signal. did you try starting it up with the accord wire just to see?
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