Failed ignitor, or ignition pickup?? Help plz

[Kevin]

Opinions plz

So, a little background info here. I was an ASE master tech for 15 years, so I'm plenty familiar with diagnostics, electronics, turning wrenches, etc. But that's with cars, and I haven't done it in awhile, so I'm rusty. Granted bikes aren't that much different, but just like cars, each make has their diagnostic "quirks", and I'm not familiar with them. Hoping a Kawi tech can chime in here.

Got a 2001 ZX6R 600-J2, 13k miles - the project bike from the other thread. It hasn't run in probably two years. Got it fired up tonight and found a problem with the primary ignition cutting out intermittently - probably the problem that got it initially sold and why it hasn't run for so long. Needs carb work too, but that's another story.

Here's what happens:
It'll run, then the ignition will cut out for a moment, then back on for awhile, then off for a moment and back on, usually in quick succession - enough to kill the engine. It'll continue to do this. If it's at idle, the engine dies (as expected). At higher RPMs, it'll cut out for a moment when the ignition glitches and catch itself when it comes back on and continue to run. It doesn't appear to be load related, but I could be wrong - it's got carb problems too, so it dies when I snap the throttle. The tach needle stays where it's at as the engine RPM's drop momentarily without spark. When it catches again, the tach needle snaps to the new, lower RPM. I do notice that the lights in the cluster dim momentarily when it glitches.

The problem was very prevalent when the bike was cold - to the point where it wouldn't run. As the bike warmed up, it got better, until it got to operating temp and the problem disappeared entirely and it purred like a kitten for 10 minutes without a glitch. Got up to operating temp, fans on, etc. After that, I couldn't reproduce the symptom. I'll try again in the morning when it's cold. Hoping the problem comes back, I want to know that I fixed it, not just throw (expensive) parts at it and wait for it to fail again while I'm riding in the mountains...

So here's what I've observed and measured: Standard low impedance test light on the primary side of an ignition coils (measuring the coil ground coming from the ignitor) shows that the ignitor is putting the coils directly to ground when it glitches. This happens clear as day - the test light momentarily goes to full brightness, no question about it.

Measuring the ignition pickup is where it gets a bit fuzzy. I don't have a scope to measure the wave form, just a pretty good (professional) fluke DVOM.

Resistance across the pickup:
Spec: 452 - 462 ohms.
Measured: 387 ohms cold, 502 ohms with engine at operating temp.

Cranking voltage produced by the pickup:
Spec: greater than 3.7V (DC volts measured through something called a "peak voltage adapter")
Measured: ~2.3V AC

The service manual wants me to measure the voltage with this special "peak voltage adapter" in between the pickup and a DVOM set to measure DC voltage. Of course, I don't have this special peak voltage adapter, so I'm using AC volts - that's how I would measure this same style magnetic pickup on a car.

While running and monitoring the AC voltage produced by the pickup, I see the voltage increase with RPM, between ~8-10V at idle to ~20V at ~3000 RPM. I don't observe the DVOM voltage dropping out when it glitches, but the DVOM may not be fast enough. I've captured the glitch with the min/max function on my DVOM but cannot confirm that the signal is dropping out - either it's not happening or the meter does not catch it in the min/max readings. The meter says it will catch transients of more than 1ms, but we're talking about a sine wave produced by a magnetic pickup, not straight up AC voltage. I wish I had a scope - it's the proper way to measure the sensor's output.

So, according to the resistance measurement, it's out of spec *maybe*, depending on the temp it should be measured at, which the service manual does not specify.

According to the voltage reading, it's out of spec while cranking *maybe*, since I'm not using the proper measurement tool.

In my experience, ignition modules usually fail when they get warmed up, pickups, when they're cold. No abnormal voltage drop anywhere in the system. I have not checked the power and grounds to the ignitor - didn't seem like the type of problem that could cause this symptom, and the only place I can think of where the power to the ignitor could momentarily drop would be through the ignition switch, and I just can't imagine an ignition switch behaving this way. As always, I could be wrong.

My gut tells me it's the ignitor, but also that it could be the pickup, but my tools *kind of* tell me it's the pickup.

Any thoughts? Tricks to testing these things?

TIA!

[brennahm]

Those boxes rarely go bad.

You already admitted you have carb issues, you CANNOT expect your bike to function when the intake system is malfunctioning. Eliminate known problems first.

[Kevin]

I am eliminating known problems first. On a bike that hasn't run for two years, I expect to rebuild the carbs. But a fuel system problem won't cause the CDI to ground the ignition coils. First fix the things that are falling off, then fix the one staring you in the face. Then go after the rest.

I'm not expecting the bike to function - I'm expecting to pinpoint and repair the obvious problem with the ignition system, which is causing the bike not to run before I move on to the malfunctioning carbs, which are causing only a lean condition at tip-in and off the idle circuit.

Why do I get the feeling that you're doggin on me because I called you out on the other thread?

Even so, thank you for the feedback about the CDI's rarely failing. I thought the same thing. It's one more clue that it's the pickup. Besides, the pickup is the cheaper of the two (if I'm gonna throw parts, that is.)

[Bashed]

I had a simular experiance with a 98 zx9 back in the day. You say the problem went away essentially when it got warm. The part on the motor (pickup) will get hot with the temp rising, unlike the cdi which will not as it is not bolted to the engine. If I was an internet betting man I would replace the pickup from your description of symptoms. Like others have said, cdi rarely go bad, but a few models have, and usually you can smack the unit to induce an occurance, if indeed this is the case. Late 80's honda's inpaticular. My problem ended up being a faulty connecter @ the cdi unit.

[Kevin]

LOL - glad I'm not the only one that knows that trick! I was smacking it with a screwdriver handle last night after it stopped acting up, but couldn't induce the problem. I'm off to steele's to see a man about a pickup.