CDI Trouble?

[Planesmaker]

Of course, I was referring to the ground wire to swithes that turn ignition off, sorry if ambiguous. Tom

[Wheels]

I installed another CDI yesterday and the result was a total failure at the right mag check. The replacement CDI is suspect as it had been removed after a similar problem to mine, but I will switch the cannon plugs this morning and see if the problem moves to the other side, if so, great! I"ll order a new CDI, if it doesn't, boohoo as the adventure unfolds.

[trentp]

I had this same issue recently, we found that one of the wires going from the ignition switch to the module was worn down and was grounding out. We pulled the wire away from the metal clamp it was in and it has been perfect ever since.

[Wheels]

Just got a call from the test facility. The module failed. I have a new one on order. They must be very proud of the little fella cause it cost me 900 + dollars. I hope the other one is ok. Do they usually die in pairs?

[68niou1]

I'm not a smart guy- but I don't understand how you only had failure on one side and both modules are bad? Does not make any sense to me. Also I don't believe it is common to have both modules fail at the same time- that's why I had a spare

[Dusty]

Ignition modules
one thing that appears to happen is the modules fail to provide ignition for startup( having run perfectly the day before ,and usually not at a convenient location)
We suspect that one fails first but isn't detected as the engine starts ok and a mag test doesn't show anything wrong as the speed is well above normal cranking speed
When the other follows you're stuck(what appears to be two dead modules)
In aircraft with dual kill switches we will sometimes start on left or right mag only ( this wont work with combo switches) so far we havn't got a definitive answer but think we may be on to something,
Just hope this may help

[Wheels]

Found the problem. A broken wire (red wire) on the harness at the bullet connector. spliced a new section in and replaced the connector. No abnormal ops.
I used the pin method to find the break but it took a long time. because the break was at the connector and it wasn't a complete break. the couple of strands of wire that were still connected gave the indication of continuity but the "limpness" of the wire end indicated the break. I eventually broke the wire inside the rubber sheath while searching that area. Wow. What a lucky break. ha ha.
Test flight went well yesterday. Just made a lap. Today is a heavy weather day, so I am washing, waxing, and polishing.

[Dave S]

Wheels,

"What a lucky break" love the humor!

Got a question. There have been many comments on the relative merits or lack thereof on soldered vs crimped connectors. Hard to beat actual experience as opposed to theory. Was the offending break on a soldered or crimped connection? Also, can you comment on the length of service of the particular connector (years/hours).

Always looking for info which will help increase reliability of our craft.

Sincerely,

Dave S
KF 7 Trigear
912ULS Warp Drive

St Paul, MN

[Slyfox]

my opinion. with all my years working on cars and such. if you know how to solder. nothing else can beat it.

[Wheels]

Dave the calendar age of the plane engine install is 1999. Actual flight time is 590 hours. always hangared. Engine removed twice for maintenance on water empellor and oil seal replacement, then once for engine mount crack. These maintenance ops resulted in obvious disconnection and re connection of the harness and probably didn't help anything. the crimp was aircraft quality and I used the same method for the repair. I will have the boys at the local Avionics repair shop check my work and redo any suspected weakness.
I wrapped the entire bullet connection bundle in silicone self galvenizing tape. Then zip tied it for security. It aint movin.