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Re: Fuel Flow all over the place
Posted: Mon Aug 01, 2022 4:59 pm
by azjoe67
I'll have to break out my scope, see if it shows anything.
In the mean time I moved the FT-60 to FF2 and it's not fixed, but better. On FF1 I would see 3-6GPH fluctuations, on FF2 it's down to 1-2.5.
Re: Fuel Flow all over the place
Posted: Mon Aug 22, 2022 10:42 am
by Markdun
I scoped my erratic FF measurements (Red Cube, Rdac XF, Jabiru 2200, Xtreme EFIS) and we found a 60v negative spike on the ground. Fix was installing a different voltage regulator.
Re: Fuel Flow all over the place
Posted: Mon Aug 22, 2022 2:43 pm
by rainier
Yeah, those regulators have been trouble for a long time. Usually radio noise. First time I read that it affects a fuel flow sender.
Re: Fuel Flow all over the place
Posted: Tue Aug 23, 2022 1:11 pm
by azjoe67
Interesting. I haven't checked my alternator / regulator. It's worth a look.
Re: Fuel Flow all over the place
Posted: Tue Sep 20, 2022 5:07 pm
by azjoe67
I'm stumped. I've tried everything y'all have recommended, no joy.
I get the same bouncy reading with two different FT-60. I've tried known clean, measured clean, isolated power, no joy. (My ship's power didn't give me anything unusual on the scope). I've tried both FF1 and FF2, same readings. I've moved the FT-60 all over the place to see if placement makes a difference. Nope. I've tried both 5V and 12V on the pullup resistor. I'm on the clean 12V right now. No change. About the only thing I haven't tried is to use the clean power on both the FT-60 and the RDAC.
Any more thoughts?
Thanks.