Question for someone running the older Electroair system

Jbon · #1 02-09-2016, 06:53 PM

Hi, I just bought an RV6A which has a Jeff Rose Electroair setup in place of the right mag. The builder installed the Advance Meter with a toggle switch so you can turn the unit off to the default 25 degrees.

it doesn't seem to be working the way I would expect. The manual says that the unit is set at zero advance when RPM's are below 500 (to aid starting). Given this, I would expect to see "0.0" on the meter with the engine stopped. I'm seeing about 18.7. With the engine running at idle, the value is about 21. If I turn the switch off, I see 18.9. I should see 25 with the switch off. Correct?

My RPM drop when switching to the EIS during runup is about 175, and the engine runs a bit rough. I'm going to check the lower plugs, but I'm still thinking these meter readings are not correct and that there's a problem with the unit. If so, would the problem be in the module? Can these older units be repaired?

Thanks for the help.

FasGlas · #2 02-09-2016, 07:34 PM

Yes, it's working correctly. The engine starts at 0 degs and goes up to 18 degs at idle. This is set by one of the trim pots under the MAP box. The digital meter reads the mV from the advance pin on the main unit. It's showing the advance that it's set to when it starts. The Electro timing has nothing to do with the timing set at installation, you must install the timing pin and set the MTH to 0 degs (if you're using an MTH). You should see the advance go as high as 40 degs at high altitudes in cruise settings. Check your plugs and wires, make sure that are good. You can set the plug gaps to .036 or more with this system.

Don't forget that the magneto is set at 25 degs, so if the EI is under 25 degs it's less advanced than the mag and will the RPM drop will be larger. Watch the EI meter and see what it's showing you.

Jbon · #3 02-09-2016, 09:58 PM

Hi, Thanks for the reply. I guess I'm still confused. The "18" reading is with the engine shut down. When I start, I'm seeing around 21 at idle.

Besides that, when I tun the switch off, I would expect to see the unit default to 25, but I'm seeing a little over 18.

One thing I'm questioning is the integrity of the MAP hose to the module. Would a leaky line explain what I'm seeing? Still though, I don't understand why turning the unit off doesn't cause the advance to default to 25.

Thanks for helping me understand this.

flyboy1963 · #4 02-09-2016, 10:29 PM

I had excellent service from Michael at ElectroAir, even thought I bought a quite old 'gold' unit. Why not try them?
My 'kit' ( box full of stuff) came with 2 voltmeters that could be wired to show quite different things. Perhaps yours is showing voltage, not advance degrees, or some such thing; there are troubleshooting and install manuals you can download from their site, if that's helpful info?

Michael Kobylik <sales@electroair.net> if this is still current.

FasGlas · #5 02-09-2016, 10:48 PM

You are not reading the advance, you are reading the millivolts coming from the advance pin on the EI. They are 2 different things, this is a preset advance. This is what the EI will advance to after the engine starts, but the advance is RPM based and then MAP based. If you go the ElectroAir web page you can see the programmed RPM advance curve. At the slowest idle the advance will start at the preset 18 degs (or whatever you set it to). To test the MAP sensor for leaks just remove the hose and blow or suck into it and see if it holds pressure. If you connect a timing light to the engine you can see the advance working with RPM or MAP. These are great high energy systems.

BTW, what the 25 deg / Var switch is doing is shorting out the MAP sensor wire to the EI. What this does is stop the MAP advance so the total advance will stop at the peak of the RPM advance.

Pat Falley · #6 02-10-2016, 09:59 AM

I have a gold unit. At last condition inspection I noticed the MP hose was loose, it failed just inside the box. It was easy to replace. I have basic engine instruments, didn't really notice any change before or after.

Jbon · #7 02-11-2016, 09:16 AM

Quote:

Originally Posted by Pat Falley

I have a gold unit. At last condition inspection I noticed the MP hose was loose, it failed just inside the box. It was easy to replace. I have basic engine instruments, didn't really notice any change before or after.

Some good information here. My manifold pressure line is leaking, and I'm going to replace it today. You said that your MP hose failed just inside the box. Mine has a metal nipple where the hose attaches. My box seems to be riveted closed. Are you saying that there is a hose inside the box? If so, that's probably toast as well.

FasGlas · #8 02-11-2016, 09:48 AM

The rubber line going into the MAP box is swedged on a brass fitting. Here's how to change it. Cut the rubber hose at the end of the brass fitting and take some small tools and remove all the rubber out of the fitting, do not damage the brass fitting. Go to the auto parts store and get some 1/8" silicon hose and some RTV. Start to slide the new hose into the fitting, just a 1/4" or so, then apply a small amount of RTV around the hose and slide it all the way down, make sure there's some RTV all around the fitting. Let it dry and it will work like new and the silicon won't rot like the old rubber did.

Jbon · #9 02-12-2016, 08:31 AM

Quote:

Originally Posted by FasGlas

The rubber line going into the MAP box is swedged on a brass fitting. Here's how to change it. . . .

Someone had already changed this line, butting the new hose to the nipple and holding it in place with a piece of heat shrink. No wonder it was leaking! I added some RTV and a hose clamp, and it seems to be tight. Now at idle I'm seeing 27.7 on the meter instead of 20.7, so there's that.

I pulled the lower plugs and found them in fine shape. The ignition leads are 18 years old, but with only 200 + hours on them. They look good, but because of their age, I'm thinking of replacing them.

1800 RPM run-up is still showing a 150 RPM drop (vs 50 on the mag), but from what FasGlas is saying the different advance values account for that. Next, I'm going to take it up to altitude and see how the advance is working.

Thanks!

Stu McCurdy · #10 02-12-2016, 08:45 AM

Remember those blue ignition leads have a fine carbon center wire. When you bend them over onto the outside of the blue insulation before crimping the plug connector, it is very possible to break the carbon center. Be very careful to make an easy loop when you bend it over (I use an awl to bend around). Then use a meter to make sure you have good connectivity end to end.