EIS noise

[hudgin]

Found that the spark plug insulators on the inside of 6 of the plugs had a dark black soot spot on them. I interpeted that to be cracks so I replaced them. Then I crawled up under the insrtument panel and rerouted the antenna wire that I had tied in with the power wire for the EIS. Will fly it tomorrow.

[hudgin]

I went flying and it still has the radio noise. Before the noise was kind of a hiss along with a popping. The hiss is now gone and the popping more pronounced. When I switchd to the mag all noises went away whatsoever. Then the all radios quit after 4 touch n goes so had to land nodo. Come to find out it my headset quit. Interestingly the radio noise doesn't start till you get off the ground. I guess I will shield the power wire to the EIS.

[rv9av8tr]

This happened to me once, I found one Electronic Ign plug wire was loose and the "popping" noise was the plug wire sparking. Push on all your plug wire sockets (both ends) and make sure they are "snapped" in place.

[hudgin]

I will check that again. I have REM37BY plugs and the wires have that spring on the end of them. Before I tighten them down I check to see if they have spring tension of them and pop back out. On the coils I check to see if they stay snapped in cause of the air pressure inside the cap pushes them back off.

The plane is down now cause we are putting in an electric aileron trim system and louvers in the cowl.

[Rainier Lamers]

Originally Posted by hudgin

I went flying and it still has the radio noise. Before the noise was kind of a hiss along with a popping. The hiss is now gone and the popping more pronounced. When I switched to the mag all noises went away whatsoever. Then the all radios quit after 4 touch n goes so had to land nodo. Come to find out it my headset quit. Interestingly the radio noise doesn't start till you get off the ground. I guess I will shield the power wire to the EIS.

Is your popping sound related to engine RPM ?
If not I may have a suggestion:

It is very possible to introduce spark discharges between various parts of your airframe if they are not electrically connected (or the connection has corroded).
This is directly related to airflow and tends to happen in dry conditions. This is one of the reasons all metal work in an aircraft needs to be electrically connected to each other (and to the negative supply rail preferably at a single point).
Cases of spark discharges inside engine bays have been known to be responsible for engine fires if mixed with fuel/vapour leaks. Ensure that all metal parts like engine mounts, radiators etc are connected in particular if you are using rubber shock mounts (which make beautiful isolators).

In a difficult case some time back we only managed to find the location of the spark discharge by running the aircraft engine in darkness - it was discharging between a coolant radiator which was isolated right across nearly two inches of space into a mounting bracket. Every time it did that there was a strong "pop" on the intercom. During daylight the spark was almost invisible.

Rainier
CEO MGL Avionics

[hudgin]

I have just assumed that it was in sinc with the RPM cause it is deffinatly related to the EIS. At one time taxing back to the hanger you could barely here it and it seemed to be in sinc with the RPM. There is an antenna farm about 10 south of KRBD which also seems to have something to do with it. When you are more than 20 miles away from them the noise is gone. But it will come back sometimes with a vengance but go away just as quick. The other day when I flew it the noise didn't come back till I was on short final. Shielding the power wire made no difference.

[steve carter]

I am chasing the same problem. Have replaced all plugs and have ohmed all wires with no defect found. Will check power wire but noise is definitely coming from EIS and not mag. I am firing bottom plugs (IO 540) with electroair EIS. Still looking for source of noise

[hudgin]

We still have the noise in our radios but not near as bad. As time has gone by I have seperated the ignition wires from the CHT and EGT harness and shielded the ignition wire at the switch all the way to the control box and seperated that wire from rest of the harness. I read tht if I had automotve plugs the problem would go away. I also read that the battery ground wire and engine grounds needs to be one of those multi stranded flat wires like what the current Cessna's with the glass panels use. I haven't done anything about that yet cause the avionics factory rep is coming out next week to look at them to repair and update some issues.

[G3i Ignition]

Where does your electroair power come from? The main power lead could have some ripple in it. Move it to the switched side of the master solenoid with a circuit breaker in line. Get it away from avionics/main buss.
May need to install a 25 ? 26kfu cap in line with this lead also to filter and aid in noise suppression ripple.
Thomas S.
www.G3ignition.com

[hudgin]

That is how it is wired. When you say get it away from the avionics/main buss, how far? It was in the bundel so I took it out and ran it by it self and moved it so that for most of the length it is at least 1/4 inch and as much as 3 inches from the rest of the bundel. I don't have any type of filter in it. Interestingly yesterday there was no noise at all except from another airplane that was quite a distance away.