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VT80BL idle unstable

Old 02-01-2020, 03:38 PM
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Rudeboy
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Default VT80BL idle unstable

Hello,

At low speeds, the rpm of the fuel pump on my VT80BL is unstable.
You can hear this when the engine is at idle or slightly above.
You can also see it when using the pump test function to prime the fuel line : the fuel does not move at an even speed through the line.
In this video you can hear the oscillation at idle


Do you think this is a pump issue, or could it be something in the control of the pump by the ECU?
The engine runs fine otherwise, you can only hear the oscillation at low rpm.

Regards
Winibald Croux.

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Old 02-01-2020, 08:18 PM
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Try a throttle relearn and check the pulse of the throttle
Old 02-20-2020, 06:00 PM
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Rudeboy
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I've tried using different pulsewidths for cut-off, start-idle and full power settings
The oscillation stays the same.
It makes the same noise using the prime/pump test feature in the fadec, even without a receiver connected. So I doubt it's a receiver pulsewidth issue.

On diesel the oscillation is nearly gone, I suspect because that fuel is a little more viscous.

Could it be my pump is just "loose"? The engine has 17 hours now.

Regards
Winibald
Old 02-20-2020, 08:29 PM
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Originally Posted by Rudeboy View Post
I've tried using different pulsewidths for cut-off, start-idle and full power settings
The oscillation stays the same.
It makes the same noise using the prime/pump test feature in the fadec, even without a receiver connected. So I doubt it's a receiver pulsewidth issue.

On diesel the oscillation is nearly gone, I suspect because that fuel is a little more viscous.

Could it be my pump is just "loose"? The engine has 17 hours now.

Regards
Winibald
The easiest thing would be to try another pump, its hard to tell without looking at it.
Old 03-15-2020, 03:40 PM
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Kcripto
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Same happen with my bt80 brushless, I connect the pump backwards in the connector, invert the lines in the pump and test, I discovered this by trial and error.
Old 07-02-2021, 02:50 AM
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Old 07-02-2021, 02:50 AM
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Old 07-02-2021, 02:50 AM
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Old 07-02-2021, 02:51 AM
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Old 07-02-2021, 02:51 AM
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