?ECU failure

[carym]

It has now happened to me. About 750 hours on engines. Here is a copy of the email I sent to my mechanic this weekend.

I think I have an ECU failure. A couple of weeks ago when I went to do a run up the left engine ECU check didn't do anything. I pulled the left engine ECU breaker and pushed it back in and retested but again I got no response. I then shut down (turning off everything). When I restarted the plane everything seemed to work normally, so I assumed it was just computer startup glitch.

I decided to do some local flying today. Again, when I pressed the ECU test button on the left engine nothing happened. I pulled the left ECU breaker and tried again but nothing happened again. When I flipped the left ECU switch to ECU B there wasn't any engine "shutter" as it should happen. I then pulled the left ECU A breaker and nothing happened. But, when I pulled the left ECU B breaker the engine quit. It seems that I have a bad left ECU A. But, if that is all I would think that when pressing the ECU test button something should happen.

I am reluctant to fly the plane over to him, even though it is only 35 miles away. Would anyone else fly the plane to a certified mechanic knowing that one of the 2 ECU's on one engine apppears to have failed?

[RC7]

Did you get any ECU failure messages? Is it possible that just the ECU test button is the problem?

[carym]

Did you get any ECU failure messages? Is it possible that just the ECU test button is the problem?

Thanks for the response. No ECU failure messages. That was puzzling and made me think it was just the test button problem, too, until I pulled the left ECU B breaker and the engine quit! I actually did this several times to make sure that I did things correctly, pulling the ECU A breaker did nothing, pulling the ECU B breaker caused the engine to quit every time.

[Doug]

It has now happened to me. About 750 hours on engines. Here is a copy of the email I sent to my mechanic this weekend.

I think I have an ECU failure. A couple of weeks ago when I went to do a run up the left engine ECU check didn't do anything. I pulled the left engine ECU breaker and pushed it back in and retested but again I got no response. I then shut down (turning off everything). When I restarted the plane everything seemed to work normally, so I assumed it was just computer startup glitch.

I decided to do some local flying today. Again, when I pressed the ECU test button on the left engine nothing happened. I pulled the left ECU breaker and tried again but nothing happened again. When I flipped the left ECU switch to ECU B there wasn't any engine "shutter" as it should happen. I then pulled the left ECU A breaker and nothing happened. But, when I pulled the left ECU B breaker the engine quit. It seems that I have a bad left ECU A. But, if that is all I would think that when pressing the ECU test button something should happen.

I am reluctant to fly the plane over to him, even though it is only 35 miles away. Would anyone else fly the plane to a certified mechanic knowing that one of the 2 ECU's on one engine apppears to have failed?

Cary

Sorry to hear, I agree that its likely more than just a bad switch. It almost as if the complete B ecu for the engine has failed, are there any in-line fuses in that loop? Do you have any announcuations?

Be interesting to hear what your mechanic thinks and his advice on flying plane to him. If he's having trouble getting answers I can pass along the North American contact for Technify.

Best of luck

[carym]

Sorry to hear, I agree that its likely more than just a bad switch. It almost as if the complete B ecu for the engine has failed, are there any in-line fuses in that loop? Do you have any announcuations?

Be interesting to hear what your mechanic thinks and his advice on flying plane to him. If he's having trouble getting answers I can pass along the North American contact for Technify.

Best of luck

It is like the ECU A has failed on that engine, but I just don't understand the lack of annunciations. There is no in-line fuse, only the circuit breakers.

My mechanic says that I need to get the plane to him to be able to do all the testing required. He points out (although he is not the one flying) that I really only have to worry about the engine failing on takeoff!!! He has too much going on right now and won't be able to get to it for a few weeks, so that will give me time to get my courage up to fly the plane when I know the ECU (or something in that circuit) is bad.

[Aart]

First failure in about 750 hours. Not too bad.. I've had a few, but they did come up as 'ECU fail' on the display. And btw always turned to be a spike from some sensor and could easily be re-set. Your indications are indeed a bit puzzling.

Out of interest. Here is Europe the ECU's need to be factory checked every 5 years. Does not apply in North America?

As to flying to the service station with one ECU: what are the chances of ECU-B failing at that take-off.. Plus you are going to be on your toes during that take-off, and you are going to be flying a light plane. I'd say, the risk here is very small. But here I am, in my comfy chair

[GHY92368]

With my DA-42TDI, I recently had an issue with my right ECU B. I had the same issue that my mechanic was about 40nm away and told me to just fly the plane to him. He explained the theory with redundant systems and why there is two ECU's per engine. I relied on my single engine training and decided to fly. I flew the plane to him last week without incident and is now being repaired. I am not recommending you should fly your plane with any mechanical issues but letting you know that I decided to fly my plane based on my comfort level. You should make your decision to fly based on your own comfort level. Good luck!!

[carym]

First failure in about 750 hours. Not too bad.. I've had a few, but they did come up as 'ECU fail' on the display. And btw always turned to be a spike from some sensor and could easily be re-set. Your indications are indeed a bit puzzling.

I, too, have had a few ECU fails that were easily reset without further issues. This time it doesn't look the same. I am hoping it is just an electrical problem (like a connector) rather than a fried ECU.

Out of interest. Here is Europe the ECU's need to be factory checked every 5 years. Does not apply in North America?

It is not clear, just as the prop overhaul issue isn't clear. However, I believe the consensus in the US would be that it is not required and, therefore, it hasn't been done.

As to flying to the service station with one ECU: what are the chances of ECU-B failing at that take-off.. Plus you are going to be on your toes during that take-off, and you are going to be flying a light plane. I'd say, the risk here is very small. But here I am, in my comfy chair

I think I will need your comfy chair . Clearly, both the POH and the engine manual say DO NOT FLY. If I see any sign of engine abnormality during takeoff roll I will shut down on runway (we have a 5000 foot runway). I probably will not retract gear until above 1000 feet AGL in case a voltage drop during gear activation causes an ECU failure. I will also ask for "flight following" from ATC before I depart. Any other suggestions from you or others would be greatly appreciated.

[GHY92368]

I should elaborate more with my ECU issue. My Right ECU B fail, I believe is a sensor issue. When I swap ECU's both function properly. Your issue more than likely is a bad ECU.
Any POH or engine manual for any plane is going to say DO NOT FLY with any engine abnormalities. I recommended you do not fly. I am just letting you know what I did and how it ended up.

[Steve]

Cary:

Do you need a ferry permit to make the flight? I would assume that the aircraft is not airworthy with an INOP ECU, but don't know for sure. I also suspect a bad connector somewhere. Can you get at them easily to reseat them? Good luck,

Steve