I'd like some help if this sounds familiar to anyone. I posted this on FG in the 2.4 section also but wanted to try here in the general forum.

I've been flying my TBM P40 with a DA 85 for a few months now. About 3 weeks ago, I had what I thought was an engine problem when the motor would cut out at some speeds usually downlines. It was consistient. Then the problem got worse and I noticed that it was not the motor's fault because I would watch the throttle servo go to idle when I'm just running up in the pits an obvious failsafe condition.

Range checks WITHOUT motor running are good. Today I switched to a new RX and even switched to a different TX, and all have the problem. I changed to a new throttle servo also. Range check with motor running is VERY BAD it goes to idle immediately and I can see the failsafe trying to activate at most throttle speeds when I'm standing right over the airplane (it pulses for a half second or so and makes the motor sound like it's hesitating, but really it's just the throttle commanding it). This will happen with me simply holding the RX in my hand (either RX) with only the throttle hooked up, and with either of two TX's I am using for test.

Perhaps I may have put some stress on the spark plug wire in fishing it through the hole in the cowl in the past month? Are the spark plug wires fragile? Someone told me that if there was arcing inside with a broken "carbon wire" in that area it could give interference. I think he was talking from automotive experince.

My question is I thought 2.4 would filter out such noise? I have seen threads where 2.4 users share a SINGLE battery for both RX and IGN, but I guess what I'm asking is it possible that the high voltage side of the circuit is more likely to cause proglems if it arcs?

If one can share a battery with IGN and RX, it seems obvious that position of the components near each other (which I understand was a big no-no with 72MHz gear) with 2.4 equipment wouldn't seem to matter. I do have the RX batter near the carb, and the ign module is also near the carb, about 5" away. The throttle and Ign switches are separated by only 3" and that's the closest their wires get to each other.

The thing that bugs me is I had beautiful performance since mid July and after Labor Day something changed drastically, so it seems to point to something other than equipment layout.

The spark plug cap is on all the way, but I did need to repair the red shrink tube which bridges where the braided shield enters the metal cap. When the plug floods I always need to pull the cap off with needle nose pliers through a small hole due to the cowl hiding everything. Sometimes I pull too hard and the cap gets jammed in the hole maybe kinking the wire?

I just thought of something else. I have both the sensor wire and the spark cable going through the same hole in the fiberglass fuselage from the ign to the motor. Both are wrapped separately in plastic coil protector, but maybe that has found a way to work loose and fray? I wonder if there would be a path for noise to enter into the RX back through the sensor wire.

Does anyone have experience in this area?

thanks,
Joe