No PTANK Sensor Output When Using Hybrid Tune - Fuel Gauge Issues - Negative Pressure Buildup

FlashPro questions & answers specific to the 2006-2011 Americas Civic Si
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funktech
Posts: 1
Joined: Sun Oct 09, 2022 11:10 am

No PTANK Sensor Output When Using Hybrid Tune - Fuel Gauge Issues - Negative Pressure Buildup

Post by funktech »

Hello,

When using a hybrid calibration on my 2009 FA5, the data logs do not have any sensor data from the PTANK sensor.

I am pretty sure the vapor canister vent solenoid stays shut the entire time the engine is running. This results in a lot of negative pressure building up in the fuel tank to the point it starts to deform. After shutting off the engine, pressure comes to equilibrium with ambient atmospheric pressure and it makes a lot of noise for a few seconds as the tank expands. If I disconnect the vent valve electrical connector on the charcoal canister, the pressure problem goes away.

My fuel gauge is unreliable. I ran out of gas when the fuel gauge had 3 bars left. When I fill the tank, the gauge doesn't indicate a full tank, its about 3-4 bars shy of full. After driving around for awhile, it indicates a full tank but then does not come down until after driving close to 100 miles.

I have a one-way check valve from the purge solenoid that mounts next to the intake manifold under the hood, during research I realized I could be loosing boost if I don't have a check valve in place.

I am working with E-Tunez, they were aware i was having some issues, but once I confirmed the exact behaviour of the evap system, they gave me a different tune that uses the base-map from an Asian civic Si.

I think I found a forum post that seems closely related to the problem I am having, but it is old - around the time Hondata started to offer the hybrid tune instead of having to choose between AFM or MAP based tunes. viewtopic.php?t=16501&start=30

Before I flashed the new tune, I reconnected the electrical connector on the vapor canister vent solenoid. When I loaded the tune, I received a warning in FlashPro mgr. about the tune being a race tune and new features are not supported and that I may have fuel tank issues. After loading the calibration, the PTANK sensor now has output and the pressure issue in the fuel tank is gone.

Has anyone else out there dealt with this issue, what was the solution? I was really liking the hybrid tune I was running, this alternative tune just doesn't feel the same. Exhaust sounds different, throttle response is different, its bucking a little in lower gears when engine is cold.

Thanks for reading.
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