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EIS noise

H

hudgin

Well Known Member
I bought a IO-360-A3B6D specifically to have an electronic ignition. We put an Electroair system on it. It has so much radio noise it is annoying. All the grounds are on the same point on both sides of the firewall and the engine is grounded to the same spot. Any ideas would be appreciated. Thanks, Doug
 
Did you buy the Electroair kit and use their spark plug wire?


http://www.electroair.net/faqs.html

Can I re-use my aircraft spark plug harness with the EIS?
No, you can not use a copper wire, or solid core harness. You have to use a noise suppression (a.k.a. resistive) spark plug wire in order to prevent unwanted RF noise from damaging the controller. Electroair supplies the appropriate harness wire with attaching hardware to complete your installation.
 
I purchased thier kit and used every thing in it including thier wires. I am aware of thier requirement to use thier supplied harness. Thier instructions also require that the wires be seperated by a certain amount so I bought some wire seperators from a hot rod supplier. I thought it would run better if I ran the EIS on the bottom plugs and the mag on the top. I am using REM37BY plugs set to the recomended gap. Thanks
 
EIS to top plugs

Klaus once told me it's best to run the EIS to all 4 top plugs and mag to bottom plugs. I think the reasoning is to avoid oil fouling of the EIS plugs, since they usually will be firing first.
 
Just got a call from Electroair and he suggested that the power wire was too close to an antenna coaxial. Or that the plug end of a wire might be defective. (Tail poking out the side or defective plug.) Well I happen to know that an antenna coaxial on the inside of the cockpit is going thru the same mounting hole as the EIS power wire with about a half inch seperation. It gives me somthing to look for.
 
I suggest you pull the bnc connector off the radio and run the engine first. That will tell you if EMI is radiated thru the coax shield of the antenna lead.
 
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.
 
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.
 
Ignition "popping" sound

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.
 
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.
 
hudgin said:
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.
Click to expand...

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
 
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.
 
electroair ignition noise

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
 
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.
 
On your EMI

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
 
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.
 
Going to the switched side of the master solenoid is the best place for + power, the battery absorbs and stabilizes power surges also. The 3? should be sufficient, 6? is the best, however not always possible. There is always some EMI in the main power feed from the EI coil divers as they charge and discharge. A 25 ?26kuf cap filter would still be beneficial, and also clean up any other EMI in the electrical system.
Thomas S.
www.G3ignition.com
 
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