I have a new BME 102 EVO thatran great for the first 12 flites then it started acting up, quit in the air and would not start. Tried again today and isolated it to the ignition system. I was not getting any spark but when I plugged the battery in to the ign directly( to check the switches) it would spark. No spark by prop rotation however. This would lead me to suspect the H.E. sensor or the ign box itself. Are the sensors prone to failure.
I ran a Pro-spark for years and am familiar with intermitents in wiring. I checked under all the heatshrink and could not see anything but one has to almost cut or redo the wires themselves to be sure.
Is there any way to check the sensor with a multimetre? I see on C&H site they have an ignition tester. Are all three wires active?
I also had a plug cap come off in flite. I noticed the Bosch metal cap version but does the NGK short reach plug work in the BME?

Yes I emailed BME but I want to be back torque rolling soon

How did you get the spark without triggering the HE pulseswitch?

Which CH ignition module do you have? Do you have the Synchro-Spark built in, or external?

It's possible that your pulse switch is bad, but unlikely. CH's tester is a good idea, IMO, to check all the wiring and the pulse switch.

Rather than calling BME, call Bill at CH about this. BME makes the engine and slaps on the ignition from CH.

Also, are you checking for spark from both leads?

Good luck,
Erich

the ignition will fire when turned on and off, which is a GOOD way to test the sensor..The tester fires the ignition without the sensor, but does not directly test the sensor....The sensor is bad if the ignition fires when turned on and off, but not when the crank is rotated...There is no way a sensor will be intermittent unless one of the wires is loose..Either it works or it doesn't...this only applies to U S made ignitions, the others need rpm to fire....Syncro spark modules have no effect on this, except that a syncro spark equipped ignition will fire more than once when the crank is rotated back and forth....

I am wondering about the wires going to the sensor. They have some type of glue supporting the wires for the soldered part of the wire right at the sensor. From there back I cut silicone tubing(lengthwise) to wrap around the wires. Perhaps the weight of the tubing did more harm than good? I had a tywrap at the engine mount point fitted loosely.
Interestingly I am using an EDR opt kill switch. When i bypassed the EDR I started to get interference. It did seem worse last time at the field when I bypassed it again. I remember reading the Pro-spark instructions saying that if the unit is defective it can cause interference. How the EDR covers it up is beyond me.

hate to be the harbinger of bad news, Tapio, but it's more than likely not the pickup that is bad.

First off, all plugging the ignition into and out of circuit does is charge the capacitors and then trigger them to discharge when the voltage is removed. . instant spark. THis means that the output side of the ignition AMPLIFIER circuit is good. Nothing more.

On the CH, there is a synchro spark module between the ignition pickup and the ignition amplifier. CH ignitions can be ordered with no Synchrospark, meaning fixed timing. All the synchrospark does is reatrd timing in relation to RPM. The Synchrosaprk modules CAN go bad, as evidenced that the spark is made when voltage is applied and removed.

The actual crank pickup is merely a magnetically activated transistor that uses a changing magnetic field to affect its conductivity. Magnet swings past, transistor either turns on or shuts off. . simple as that. IF this pickup is going bad, you can spin the motor over at high speed with a drill and get a spark sometimes. IF the wires have a bad spot, and are not making contact or there is a bad solder joint on the pickup, using a heavy handed "flexing" of these wires can sometimes cause contact, which will result in a spark whenever the contact is made and then broken. This is the most likely failure point for this ignition on the BME.

One more thing, you can bypass the Synchrospark module by shorting like-colored wires on the input and output sides of the module, allowing the pickup to give a signal directly to the ignition amplifier. If you do this, and it fires when spun over, you have a bad synchrospark module. there may be a warranty issue with this, though. However, three shorting wires with alligator clips can accomplish this with little evidence of tampering

NOW. .I just had a CH ignition fail, for the SECOND time, due to a bad synchrospark module, OR the associated amplifier circuitson the inputs side of the ignition. If you have a bad transistor in the main amplifier, it can shut down the "normal" operation of the ignition but you will still get the connected/disconnected spark from the coils. It all traces back to where the failure is. I sent the ignition in, the synchrospark module was replaced I put it in the plane for 5 great flights, then parked the plane for 3 days. . Came out and tried to fire the engine and NOTHING. I have a spare crank pickup, and it did not help by changing it. Power to the ignition was 5.4 vdc, and it would spark during connect-disconnect testing.

Your best bet is to call CH ignitions. their number is 307 857 6897. They are on the web at www.ch-ignitions.com .

I raised a bit of cane when I called them about the second failure, and they sent me a new ignition as I am sending mine back in.

Best of luck getting your BME running again.

So color me wrong..A failure rate of 1 or 2 out of 1000 syncro spark circuits is pretty remote, but possible,,....I haven't (or won't) use 1000 syncro spark circuits in the foreseeable future, as most of my ignitions use mechanical advance..The failure rate of my sensors is so remote they're put into the engine with 5 minute epoxy..Usually the problem is a loose wire at the solder joint caused by flexing...The turn on/off test has always worked for me....
FWIW, the BME pickup is solidly mounted and flex is pretty remote...
My circuit has
One toroid coil, (6 wires) 3 diodes, 3 or 4 resistors, 4 capacitors, a TIP31C and a N6241 thing...Which is the amplifier ?
Sometimes when a circuit is bad I can replace the 6241 and it works again....

Gee, the whole bloody thing is a switching amplifier. No way in hell that pickup is going to turn the coils on and off all by its lonesome. Primary voltage in the coils is probably close to 50-60 volts at peak, and the supply voltage is only 4.8-6. Okay. . inductive "kick" makes the spike, but the miniscule .5-1 volt signal from the pickup would never result in a coil firing if the module was not amplifying that signal to saturate the coils during on dwell time.


BTW your "module" and the CH, 3W, and DA ignition modules all use the same basic circuitry to fire the coils. Just a simple switching amp that has the timing of its pulse controlled externally, by a Synchrospark module, mechanical advance, or the auto-advance circuits in the pickups on DA and 3W engines.

you could probably hook up a synchrospark advance/retard unit on the input side of a DA./3W style ignition and it would keep time just fine, thank you very much.

The v into the coil is in the order of 300vdc not 50-60. The sensor is just that,
it trips an SCR which dumps the HV, stored in a cap, into the coil

Thanks, TK, I forgot what that 6241 thingy was...CRS, ya know...

Thanks for the upgrade on induced voltage, TKG. I guess in the smaller coils more primary voltage is necessary to get proper seconday output. Time to reactivate my "electronics dedicated" brain cells and study this circuit a bit more closely. Since I'm constantly trying to "reinvent the wheel" anyway, maybe I can find a way to just ditch the external timing circuits normally found in these units and develop a simple, bulletproof,and adjustable circuit for timing control. Seems a serial time delay circuit, with less delay as frequency increases, would be the simplest design, and no chips involved. Add in a couple of variable resistors or inductive cans for tuning, and you'd have an infinitely adjustable timing curve.

CH's mechanical spark advance is a foolproof system too. Great for us elecronically handicapped.

I checked the lead wires carefully last night , with the beep on my multimetre also and could not find an intermittent or total discontact. I was tempted to order a second ignition but now I am wondering which one ?? My unit is the synchro spark and I could not be talked into mech. advance. I ran a Pro-Spark for hundreds of hrs with only occasional wiring probs but they seem to have gone into the shadows also.
I will call C&H , I guess they do not have e-mail, prefer to call anyways.

A friend had a spare HE sensor and now the unit would fire with both sensors. I will ship the ignition unit back and hope it doesnt take all summer to come back!

Glad you have it figured out, Tapio. Let us know how it all turns out for you.