ECU A+B LEFT failure

[bohkmx]

Hi Guys

I had serious issues with the left engine and constant ECU failures, though without the engine cuts out.

So after these faults happen, then the left engine shows only full power and 2290 RPM the rest of the time. If you reset the ECU sometimes it clears the errors but the remainder of the flight the RPM is stuck on 2290. I cannot say if this is a true RPM as the power feels the same and if I lower the power then 2280-2300 RPM still remains and I just adjust the fuel flow to the same.

To reset the ECU you should remember to put on the pumps and pull alternate air, but still the engines can sort of stop for 1-2 seconds and then start again which of course is very uncomfortable.

Now we are changing the governor on the left engine, so hoping that will help, but apparently this has happened a few times so hope this helps people if they get in the same situation.

BoB

[bohkmx]

Btw when they downloaded the data, there was a memory write error so the errors could not be found which does not exactly make it easier to fix.

[carym]

If there was that much difference in RPMs you would definitely feel the asymmetric thrust. Looking at your AI it appears you were coordinated. Did you have to use a lot of rudder pressure (or trim) to remain coordinated? If not, it would suggest that the RPM output from the computer to the G1000 was inaccurate. In my experience, when there is a problem with the prop governor, you know it with asymmetric thrust. Off hand, a failure in both ECU A and ECU B makes me think that it is a sensor problem and not a mechanical issue.

Good luck figuring this out.

[bohkmx]

Yes, no pressure on the feet and pulling the power would reduce, so I agree with your assessment that it was probably not mechanical.

[bohkmx]

this seems to have been fixed now. We had the governor changed.


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[carym]

I am really surprised it was the prop governor. When I had problems with the prop governor (in my C310) it was really noticable in my feet. In fact, I ended up shutting down that engine and feathering the prop and flying the rest of the way to my home base OEI. I am glad it is fixed, but personally I would still be on the lookout for some other problem. Just be forewarned.

[egibs01]

Same thing happened to me last week. Two mild shudders out of the left engine and bing L&R ECU failure....upped the pucker factor for the last 60 miles back home. Mechanic suspected water in the fuel, enough to trip a fault, but other than the annunciation, no indication of trouble on the remainder of the flight.


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[Steve D]

I have had ECU failures on the left engine (Thielert 2.0) before. The engine carried on running but it sure does increase the "Pucker Factor". Eventually the fault was traced to the high pressure sensor on the common fuel rail. It required replacing the original sensor with a new MB design.

When a similar fault occurred on the right while on the ground. Replacement of the sensor with the new type solved the problem immediately.

[carym]

I have had ECU failures on the left engine (Thielert 2.0) before. The engine carried on running but it sure does increase the "Pucker Factor". Eventually the fault was traced to the high pressure sensor on the common fuel rail. It required replacing the original sensor with a new MB design.

When a similar fault occurred on the right while on the ground. Replacement of the sensor with the new type solved the problem immediately.

I think I've mentioned this before. I have had the same thing happen to me just after rotation on departure. Pressing the ECU TEST button rewset the fault and I kept flying to my destination (which happened to be my mechanic). Engine download showed the fault was due to a "slight" turbocharger overboast which Thielert said was not an issue and there was no need to do anything about it. Still one doesn't like to see these failure warnings.

Tomorrow we download the engine data to see why my left engine starts on, and only uses, ECU B. No one yet has been able to explain why I don't get an ECU A error , even tho it appears the ECU A is not operating. I removed the inspection plate from the left engine ECU this weekend and didn't see anything that looked loose or disconnected I'll follow up (on the other thread I started) as soon as I learn something new.