I have a great planes 300 1.60. I have installed a fuji BT-50ei on it with futaba fm receiver, 1 futaba 3004 for throttle; ailerons, elevators 3010 and rudder hitech high torque(forgot #). Flew the plane fine 5 times but now have interference with engine running. receiver mounted 2 feet from ign. module along with throttle servo(plastic connecting rod attached to throttle). I hope somebody has suggestions on how to fix this.

Before you go to any elaborate lengths, try twisting all of your servo extensions

I did try twisting all the wires. help

It is highly unlikely for twisting any wires to help. Make sure that you have not developed a loose metal to metal joint somewhere. Flying wires? Landing gear? Braces? metal clevis? etc. Also check your plug, has it carboned up? You are using a resistance plug, right?
Your antenna has not been compromised, has it, like being yanked and breaking inside the insulation (looks okay but isn't)?

I have looked for loose metal and the spark plug is resistor type. I will check antenna though. thanks

I have Fuji 50EI in new 260 Extra. Problem is range checking with antenna collapsed or with plane at far end of field. Jitters. All servos. Had base type antenna, changed to full length, no change. Seperated all leads. No change. Have a new receiver coming, will change it and xstal. Have been told that a damaged xtal can be the culprit. Also, may need a choke in the throttle leads back to the rcvr.
Talked to tech support at Hobbico, said I was doing everything right to locate the problem and if it persists to send the engine to them.
It was also suggested to me to isolate the EI module with aluminum foil grounded to the engine to test the the shield in the module was adequate.
Any others?

Make sure all your connections are tight and that no wires are near the antenna

Thanks. I've checked them all and antenna is away. Maybe the new rcvr will do the trick, I'll let you know.

If you would post pictures of the details of installation someone might observe a problem that might not be obvious to you. There is simply not enough evidence to respond.

Bill

Hi guys, Im having exactly the same prob, however, it occurs with the engine runnning, or off....I have replaced the RX's, the TX's the crystals, the batteries....no luck whatsoever. It only occurs when I move approx 6-10 ft away from it with the Tx. Sometimes when I come near to it with a glow starter, the vibrations on all the servos gets worse. It flew fine for 10 flights, and all of a sudden, without even shutting down, i turned it around and took off again, and went all over the sky as all the servos were going crazy. Pleeeeze help

The final fix for mine was I put a pcm reciever in and the problem was fixed. I have 30 - 40 flights since I went pcm, without one problem or interference. I believe I tried everything before going pcm. Hope this helps. Bill
The receiver I used was a Futaba FP-R138DP.

When I first started using gas engines I run into the interference problem. I solved it by putting a Bosch plug cover on it. I run the cover on all my gas engines now, and have never had another problem.

A club member has an identical problem. Has anyone seen a comprehensive checklist for gas engine interference on the web? He also switched to PCM but it would be good to actually find the cause of the interference.

Bill

While PCM would effectively mask the problem, it is not a true fix.
I would go back to PPM and find the problem.
Once fixed, I would recommend PCM for safety reasons.
Idle down or engine off Fail-safe

In the case of the Fuji 50IE, I have located the trouble after extensive troubleshooting. The last thing I did which showed the problem was to wrap the spark plug wire with aluminum foil, not touching either end of the wire to ground. Engine ran fine but still had some jitter from the control surfaces. Upon clipping the foil to engine ground, the engine stopped! With the foil connected to ground, the engine would not start. Took off the ground and all was well. I decided that the plug wire is leaking badly and am returning the EI module and associated wires to Hobbico for analysis.
I'll let you know what they respond.

I totally agree and am trying to encourage the club member to find the problem. Since someone else is troubleshooting I am searching for written information to give the club member to use as a guide.

Bill

Hobbico sent me a new EI module. *No info about the problem or if they looked at it, just sent a new one and returned my Bosch plug cover. Put new setup into plane-no more grounded plug wire but probelm persists to a lesser degree. Now that I have done everything in the world to this plane and engine to no avail, I have sent for a PCM receiver. I know that this masks the problem but I'd like to fly this plane before I get too much older.
I have no problem with any other gasser that I fly, and I have others of varying makes, Fuji 64, Zenoah 62, US 41, and several others with EI and without it. This Fuji 50EI is all by itself in the trouble department.

I assume that it range checks with motor off, but does not range check with motor running.

make sure that the batteries for receiver and ignition are separated. Everything related to the ignition should be separated from everything related to the receiver by at least 12" or so.

try a new spark plug. Make sure it's in tight.

if you have a rubber boot over the plug, see if you can replace that with a bosch metal boot. This is what cured my interference problem.


peter

Peter:
Have done it all and there is a Bosch cap on the plug. I'm left with the opinion that the radiation from the EI system should be addressed by the manufacturer. Hobbico services man said that people were saying that Desert Aircraft engines have plug wires with metal mesh covering. That's maybe the answer.
Pete

maybe try making a rf shield for ei module,stick it in a small clean cani and tape a metal cover over the open end the wires exit from.that should shield the radio from any rf coming from the module.i do recall reading many years ago that carbon build up on the plug caused rf problems seems that if there was no problem when new that carbon build up could be a problem.

Brand new plug.

Better to use PCM when you step up to GAS.....I know someone who had a simular problem and we found that the RX antenna was to close to the servo extentions going though the tail of the plane. Also make sure that you do not have any metal to metal at from the engine, try to use plastic clevis to hook up to engine control arm.

Did all that.

What I know for sure is that if you don’t find the problem it will eventually bite you. Posting pictures might help someone see something obvious that you may have overlooked.

Bill

Put in PCM rcvr, problem is gone. I know that I've not solved the problem, but that will wait until winter. Meanwhile, I can fly the plane.
Thanks for your suggestions.