EGT/CHT cylinder 1 reads 0

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cirimj82
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EGT/CHT cylinder 1 reads 0

Post by cirimj82 »

On a flight from Kansas to Texas, I was at 8,000 ft when a yellow FADEC Caution light flickered and I felt slight engine roughness. I quickly decreased the RPM where it seemed to fix the problem. I flew at a slower speed for a while and then started getting it again. Chose to divert to a airport in Oklahoma. The mechanic there is working with me but has no experience with a Liberty. We checked the #1 Injector, it was good. CHT/EGT sensors were swapped with #2 cylinder and it was still showing 0 on #1 (sensors are good). We are thinking this is a bad ECU (657440-1) but are looking for advice on what else it could be. I am a new owner and just looking for any advice I can get.

If the ECU is bad, does anyone know where I could get this one repaired. Boeing has a 50+ day wait on a new one and a $4200 price tag.

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Re: EGT/CHT cylinder 1 reads 0

Post by N645XL »

I'm not following what was reading 0 on cylinder #1? Was it CHT and EGT?

Did you ohm/ring out the low voltage harness servicing the #1 fault?

With two ECU's and two spark plugs I don't think it likely your CHT and EGT would go to zero. If the sensors are good I put my money on the harness wire.

Keep us posted.
Bob
P.S. Disclaimer is I'm not and A&P and never played one on TV or the movies. :-)

cirimj82
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Re: EGT/CHT cylinder 1 reads 0

Post by cirimj82 »

Thanks Bob, I’m really hoping it’s the wiring harnesses and not the ECU. The VM1000 is showing 0 for both the CHT and EGT on cylinder 1. 2-4 are showing normal.
I’m not a mechanic but I will pass along your suggestion of “ Did you ohm/ring out the low voltage harness servicing the #1 fault?” to my mechanic.
Thanks for the help, I will definitely keep you posted.
Best Regards,
Mike

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Re: EGT/CHT cylinder 1 reads 0

Post by N645XL »

Thinking about it more, have you connected a computer to the plane running the diagnostic software? If you’re getting the data to the computer I think(?) you can eliminate the harness as a suspect. I wonder if the VM1000 has a common circuit for CHT/EGT? Just thinking as I type. I don’t have the schematics handy.

cirimj82
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Re: EGT/CHT cylinder 1 reads 0

Post by cirimj82 »

My mechanic is running the diagnostic software as I type this. I am really keeping my fingers crossed that its the wiring harness and not the ECU. I will update when I get an answer. Thanks for your help Bob.

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BRADLOUTH
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Re: EGT/CHT cylinder 1 reads 0

Post by BRADLOUTH »

Trust me you do NOT want it to be the wiring harness..they now charge $17,000 for one and it takes 25 hours to replace....

Brad

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