Excess Pressure in the Gas Tank :-(

[Lee_Burough]

My TTA builds excess pressure in the gas tank on extended drives. The fuel pump is relatively quiet at first, but really howels after an hour of highway driving. Its quiet again after relieving the pressure in the gas tank.

Please help me understand how the evaporative system/cannister functions relative to fuel tank pressures....It seems to me that something isn't venting properly

What is the most likely culpret with this excess pressure? Could something be installed incorrectly?

Don't hold back, make me smart on this evaporative system

Thanks

 

[salvageV6]

ECM grounds the solenoid line to cause purging.

Must be over 176*F, over 5mph, over 1 minute run time of engine, and over a certain tps I think.

Grounding the ALDL pin port will also cause it to activate.

Check valve in the system line prevents boost from pressurizing things.

I'd check the check valve and for proper grounding of the ECM solenoid when the ALDL test is done.

Power is supplied to the solenoid via ECM/SOL fuse hot in run , bulb test, and start.

Pink is hot green is commanded ground wire.

 

[Lee_Burough]

SalageV6, thanks for the reply

I will need a little translation though....Your color code explanation for the wires went right over my head -my lack of understanding the technicalities, not your explanation I'm sure

Let me restate what I think you said, OK?

The ECM grounds the solenoid line to cause purging....I'd check the check valve and for proper grounding of the ECM solenoid when the ALDL test is done.

Grounding the ALDL pin port will also cause it to activate.

Pink is hot, green is commanded ground wire.

My confusion is about how the colors will help me to ground the ALDL pins to test the solenoid function: When I'm trying to ground the ALDL, do I just ground the pink wire? (That sounds like the wrong thing to do to me) If not, help me understand what I need to do to safely ground the ALDL to check the solonoid function.

Thanks for being patient with my ignorance here