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Electroair Ignition Vacuum Transducer
- Thread starter Vansconvert
- Start date
rocketbob
Well Known Member
It consists of some passive analog components that can be easily replaced with some basic electronics knowledge.
Did you call them? https://www.electroair.net/
BoydBirchler
Well Known Member
I have one of these systems. Electroair didn’t make them, they were purchased private label from Electromotive. Electromotive went out of business a while ago and I was about to say they they were gone. The MAP sensor came from them as did all of the other components for the original experimental system. I just followed the link and it looks like someone bought them and reopened the doors. I have a bad sensor also. The output of the sensor is inverse to the current automotive ones so they won’t work. There is a board mounted sensor and they condition the signal for the computer. They used to be impossible to deal with, but I might try again. FYI, you can just disconnect it and run with straight fixed timing. I have been doing that for a year. Curious how did yours fail? What problem was it causing?
I checked their website and it says they are not currently selling or repairing products. They are looking for somebody to buy the company.
Anyway, I went to do my run up, flipped the switch to test the advance and nothing happened. Was as if I didn't even flip the switch. The switch tested out as good.
Your system must be different than mine. I don't have a switch to flip to test the advance. The MAP sensor is totally separate from the ignition coil unit. Maybe yours is an earlier version than mine.
Take a look at the picture I posted in the original post. The manifold sensor is directly above the coil unit. But they are two separate units.
A few years ago, when I first had problems with the MAP sensor, I spoke with Mike, the owner of Electroair. I was looking for some specs for troubleshooting the system. He indicated that they bought the entire system except for the Mag sensor from Electromotive and had no info or specs for it. I got a known good unit from him and through testing created the pressure vs output curves. As of a year ago, that is how I know that the curve doesn’t line up with automotive sensors. Mike confirmed that with Electromotive out of business, they had no way to support the experimental system with parts.
I did manage to get a manual from Electromotive on the computer, and did find the MAP sensor in a manual, but no data on it.
I am certain that Jeff Rose just purchased the system from Electromotive with the RPM based advance was set to zero and the adjustment taped off. Then the MAP sensor provided “ vacuum” advance based on MAP. The system design seems to go back to technology from the 80’s.
The original problem that had with the MAP sensor was, when hot, it was consuming too much power from the computer and overloading the power supply.
Now, I am finding that the MAP advance is too much sometimes causing detonation when cruising at 60-62% power. I now have the MAP sensor disconnected.
Last year I purchased an RV-6A with a 2015 vintage ElectroAir and was having serious problems. I called up Rick Hafley at Smooth Power, Llc. https://smoothpowerllc.com/ and he went up and beyond to help me out. Sent manuals for my set up and we were able to make things work. Turned out I had a ground issue but the MAP sensor was causing too much of an advance. He suggested I cut in a switch on the Green wire that would cause the system to default to 25 degrees. I put a switch on the dash and flipping it off made everything run extremely smooth. I don't get the advantages of the advanced curve but I can do without for now as it runs perfectly. The last 80 hours have been trouble free. They even offered to upgrade to the latest version at a significant discount but the timing wasn't right. Just an option if your system can do the same. Took about a half hour to cut in the switch.
Thank you for the info.
That is it. Not made by Electroair, but purchased from Electromotive.
Crash'nF16
Member
I had a similar issue with the same style MAP sensor about a year ago on an RV-8 I had purchased. Suddenly I was seeing CHT's about 30 degrees hotter than normal on takeoff and eventually traced it to the timing being too far advanced. I wired in a switch as you did, but I also connected the timing advance signal wire to one of these. The indication is a little erratic but I can see what the controller is providing for timing advance all the time now. I even made a little photocell dimmer for it out of some components I had in an old Radio Shack electronics kit.
If you want to restore the normal timing curve, you might be able to by taking that MAP sensor apart. It has four op amp circuits, each of which has gain resistors. Two of those resistors are potentiometers. The sensor takes 5V in and scales it linearly starting at 24" MAP down to ~1v (or the opposite of that, i can't remember exactly). My sensor was just outputting 2.5V all the time regardless of the pressure it was sensing. By adjusting those two potentiometers, I was eventually able to restore the curve to begin advancing at 24" and stop advancing around 17". I'm sure there's a less gross way to do this, but I disconnected my MAP sensor line from the engine and provided the suction...myself. I had the timing advance milivolt signal hooked up to my multimeter and a friend to read me the manifold pressure my EFIS was reporting. After about 30 minutes of trial and error with the potentiometer adjustment, I had the timing curve restored.
Electroair told me they can't source the components for this sensor anymore and that I could send it in for them to bench test, but I would almost certainly need to replace the entire ignition system with a new one. I figured it would be worth it to see if I could fix it myself. I did take a look at Digikey and found that the pressure sensor it uses has been out of production for many years, but it looked like some are occasionally available on eBay. I may try to get one if that sensor does go bad some day.
The other nice thing about having the switch is that if I'm taking off from a high altitude field in the summer, I can turn the advance off to help keep my CHT's down.
Here's what the MAP sensor looks like inside. The two blue rectangular components in the top half of the image with the screws are the pots.
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