Strange CH ignition problems

[KrisW]

Not trying to start a war here. . but I'm at my wits end.

Over the last month I've gone through 2 ignitions. Both have been in my posession for a good while. Here's the symptoms:

Run great, no problems. Next day, things go downhill very rapidly. First the engine starts and runs great, then in the air, after a few minutes, I start getting roughness, misfires, actuall cutouts and then the engine catches and runs again, but after landing the engine runs smooth as silk with good power. Occasionally I will get a cutout on the ground, especially right after landing, but it's more like a glitch than stoppage. The engine also rattles badly, as if the timing is far in advance of where it should be, then will clear up and run normally, then start the entire misfire/rough running prblem again . all inside a minute.

Then it will start to bite my hand while flipping the prop, no matter how fast I swing it over. Sometimes cycling the power switch will make this go away, sometimes not. Letting things cool down a bity does not seem to alleviate the problem very much.

I was experiencing this problem at a Meet, to the point that eventually the engine would not re-start, merely giving me a little pop but not running over. Switching to my backup ignition got an immediate start with full power. Switching back to the original ignition (all within 5 minutes) finally got a start, but bad misfire and rough runnning throughout the rpm range.

Now the 2nd ignition has started to show the same exact symptoms, went to the point of no-start, seems to overly advance the timing in the air to the point that the engine is rattling and detonating, as well as misfiring and having no power.

I swapped out the entire ignition power circuit, going to a 10 amp Fromeco electronic switch, 4800 ma pack and 5.4v regulator, with no change in performance or problem. I've also switched crank pickups, but it did not seem to alleviate the problem. But who knows. . I might have 2 degraded pickups.

So. . any advice is appreciated. I've been chasing my tail on this one for over a month, and except for the ignitin boxes can't really see anything else that could be causing this.


One other thing, I'm using DA or 3W caps, with 1000 ohm resistors in the caps, on both ignitions. Is this okay to do, and can it cause problems? I'm pretty sure the leads already have resistor type shielded sparkplug leads, but can't really see any problem with using the resistors to help suppress RF interference.

And, why haven't I sent the ignitions in yet?? I'm stubborn!!!!

[bosshoss]

all i can say is, i have had the same or close to the same problem. BME 102 EVO w/ CH ign.

the Synchro Spark module went bad in the ign.

you seem to have some confusing circumstances.

my ch needs resistor plugs. I dont think the caps are resistive.

good luck.

[KrisW]

You're right hoss. . Forgot about the Resistor plugs on the CH, which the resistor caps take the place of with the non-resistor CM-6 plugs. I figured it was a problem developing with thetiming modules, but wanted some 2nd opinions before I shipped them off. Costs money for repairs, youknow.

All this information floating around inside my lil ole head. . hard to get it all sorted sometimes

My whole problem with this scenario is that I can;t get the engine to run badly on the ground, after it was totally out of whack in the air. If I could get the prblem to repeat after landing, and not just when it wanted to, I'd have sent these ignitions off immediately.

[TKG]

What engine and how old are the ignitions??

[KrisW]

	Quote: Originally Posted by TKG
	What engine and how old are the ignitions??

BME 102-110, TKG, Thanks for responding.

I have them in the mail to you, Priority Mail.

Both are in the 2-3 year old range, but one has been on the shelf for a while. Probably 150 flights on the other.

[TKG]

There is a possible problem with the 3w type caps installed on a rubber boot lead. The spike will start to damage the carbon core causing noise and bad running. If you like this cap then we need to change to the stranded wire leads like we use on the Bosch cap for the same reason

[KrisW]

	Quote: Originally Posted by TKG
	There is a possible problem with the 3w type caps installed on a rubber boot lead. The spike will start to damage the carbon core causing noise and bad running. If you like this cap then we need to change to the stranded wire leads like we use on the Bosch cap for the same reason

Sounds reasonable to me. I'm sure you guys get all sorts of stuff back from customers, and shake your heads wondering what the guy thought he was doing. If changing over to a metal core lead helps with this problem, I'm all for it. There's also the issue of kicking back during starting, and then the misfire/dropouts that occured. I'm sure you guys will look the ignitions over and give your best advice on how to proceed.

The only reason I prefer this design of cap is due to the Silicon insulator inserts, which have a much higher temperature rating than the rubber inserts a lot of people use. Give it 20 or so flights and usually one of the inserts degrades, and has to be replaced. Even with air blowing directly on the plug caps, one of the rubber inserts melted on my Falkon ignition, and all my 3W ignitions with the rubber inserts did the same thing. 3W learned a biter lesson from this, I'm sure, and now uses the same silicon inserts that DA used form the beginning. So, now, I kind of insist on using the Silicon insert plug caps, to assure against any further problems of this nature.

Thanks.

[bcchi]

	Quote: Originally Posted by KrisW
	Sounds reasonable to me. I'm sure you guys get all sorts of stuff back from customers, and shake your heads wondering what the guy thought he was doing. If changing over to a metal core lead helps with this problem, I'm all for it. There's also the issue of kicking back during starting, and then the misfire/dropouts that occured. I'm sure you guys will look the ignitions over and give your best advice on how to proceed. The only reason I prefer this design of cap is due to the Silicon insulator inserts, which have a much higher temperature rating than the rubber inserts a lot of people use. Give it 20 or so flights and usually one of the inserts degrades, and has to be replaced. Even with air blowing directly on the plug caps, one of the rubber inserts melted on my Falkon ignition, and all my 3W ignitions with the rubber inserts did the same thing. 3W learned a biter lesson from this, I'm sure, and now uses the same silicon inserts that DA used form the beginning. So, now, I kind of insist on using the Silicon insert plug caps, to assure against any further problems of this nature. Thanks.

We now have silicone boots for all spark plugs. You may have a temp related problem with the Syncro Spark modules ,depends on build date we alway check this on repairs and fix under warranty if this the problem
BCCHI

[Tired Old Man]

There's another issue that has been cropping up on the 14mm aluminum caps. Seems the metal contacts inside the cap have been opening up, breaking contact with the top of the plug at times. It causes a miss that comes and goes. The fix is to insert a short spring inside the top of the cap to assure constant contact between the cap and the plug. Retain the spring with a liberal dose of dielectric silicone grease. The spring has to have a diameter small enough to sit inside the contacts and large enough to make as much of the diameter of the plug end as possible. Better would be large enough to fit tightly around the top of the plug.

The issue is not limited to any one type of ignition, but to all that use the 14mm aluminum plug cap. If you're using a CM-6 plug then you have potential for the issue, regardless of ignition or engine type.

[krayzc]

are the connections deans plugs or something else on the ones that were giving you issues?