After traveling, there was high air pressure in the fuel tank? is it normal?

the fuel is constantly rotating round the fuel lines, the fuel is pressurized, so any fuel that is not used by the injectors is sent back to the tank.. this give a constant flow and pressure to the tank. the pressure in the tank is regulated by the pressure relay that lets air into the tank to lower the pressure. this is regulated by the ecu and your speed. if the pressure drops or is to high in the tank the engine can cut out on the fuel rail there is a fuel pressure regulator this keeps pressure on the fuel line coming into the injection system. some systems have duel line feeds from the tank for 2 rail systems, this system was not reliable due to the amount of feed pressure needed to fuel 2 lines. and can cause pressure leaks. some systems have a pressure regulator controlled by the ecu on the return line, this is more fuel efficient as it keeps the fuel at a steadier flow back to the tank and give a better fuel spray into the engine. hope this help you.

Fuel rail pressure switch poss leak would cause this smell

Hey jessica, from what you describe it sounds like a fuel pressure problem. A vehicle can have "weak" fuel pressure & may still be drivable but will not perform well on a hard acceleration. First get the fuel pressure checked and PLEASE go to someone who will use a fuel pressure gauge not stick a screwdriver in the test port and see if fuel sprays out! I believe the fuel pressure spec. for this vehicle is 55-60 psi with the key on. The codes po171,174 indicate "both banks lean" which could be caused by a lack of fuel pressure. These codes can be caused by a M.A.F. sensor problem (Mass Air Flow sensor). Common problems with M.A.F. sensors - they can get dirty and not work properly. I still highly recommend the fuel pressure test first! If it lacks pressure you know you have a bad pump. If the vehicle has a replacable fuel filter this needs to be checked & or replaced then re-check fuel pressure. If fuel pressure is OK then check for problems with the M.A.F. ( Dirty, Air leaks between sensor & engine throttle body, defective sensor) Hope this helps!

Have you actually checked the fuel pressure with and without the gas cap? If you have a tank venting (EVAP) system problem (e.g. blocked vent on gas cap, plugged canister, or one of the two vent valves stuck shut), you can draw too high a vacuum on the tank which will cause a fuel starvation problem.

You will have to figure out if it is a fuel or spark problem to proceed.
Vent in gas tank could be causing the pressure in the tank to cause a loss in pressure to the injectors. Something electrical such as a relay could be failing.
Is the check engine light on when the engine is running ?

The wash has made water seep into the IGNITION circuit, HT Circuit and the fuel system. Normally a good air pressure cleaning is needed to spray out all moisture after a wash and if not the performance of the car will be effected thereby undermining the working of the engine.

So cehck the wirings, check the HT coils and check if the fuel contains water. If so this can come up with the pumping when the tank gets empty and produce misfiring, splutter and jerks. So a check on the fuel filter will confirm this as it will be seen, if so remove and clean tank and change the filter.

Use of high pressure air to clean out the water will solve the issue. If water is within the ignition system, then remove caps, covers and blow out.

Hi, the computer has sensed through the fuel tank pressure sensor that the vapor cannister is not evacuating properly. I have pasted details on the EVAP system below. Check the purge valve on top of the engine as shown below (#1 in picture). Make sure the electrical connector is on the valve, that the wires are not damaged, and check the hose for kinks. If all looks good, I recommend you replace the valve. A new valve is $23 at autozone. Please let me know if you have more questions and thanks for using FixYa.


Description & Operation
EVAP Canister
The canister is filled with carbon pellets used to absorb and store fuel vapors. Fuel vapor is stored in the canister until the control module determines that the vapor can be consumed in the normal combustion process.
EVAP Control System
The evaporative emission (EVAP) control system limits fuel vapors from escaping into the atmosphere. Fuel tank vapors are allowed to move from the fuel tank, due to pressure in the tank, through the vapor pipe, into the EVAP canister. Carbon in the canister absorbs and stores the fuel vapors. Excess pressure is vented through the vent line and EVAP vent solenoid to atmosphere.
The EVAP canister stores the fuel vapors until the engine is able to use them. At an appropriate time, the control module will command the EVAP purge solenoid ON, open, allowing engine vacuum to be applied to the EVAP canister. With the EVAP vent solenoid OFF, open, fresh air will be drawn through the solenoid and vent line to the EVAP canister. Fresh air is drawn through the canister, pulling fuel vapors from the carbon.
The air/fuel vapor mixture continues through the EVAP purge pipe and EVAP purge solenoid into the intake manifold to be consumed during normal combustion. The control module uses several tests to determine if the EVAP system is leaking.
The EVAP system consists of the following components:
EVAP Purge Solenoid
The EVAP purge solenoid controls the flow of vapors from the EVAP system to the intake manifold. This normally closed solenoid is pulse width modulated (PWM) by the control module to precisely control the flow of fuel vapor to the engine. The solenoid will also be opened during some portions of the EVAP testing, allowing engine vacuum to enter the EVAP system.
EVAP Service Port
The EVAP service port is located in the EVAP purge pipe between the EVAP purge solenoid and the EVAP canister. The service port is identified by a green colored cap.
EVAP Vent Solenoid
The EVAP vent solenoid controls fresh airflow into the EVAP canister. The solenoid is normally open. The control module will command the solenoid closed during some EVAP tests, allowing the system to be tested for leaks.
Fuel Tank Pressure Sensor
The FTP sensor measures the difference between the pressure or vacuum in the fuel tank and outside air pressure. The control module provides a 5-volt reference and a ground to the FTP sensor. The FTP sensor provides a signal voltage back to the control module that can vary between 0.1-4.9 volts. As FTP increases, FTP sensor voltage decreases, high pressure = low voltage. As FTP decreases, FTP voltage increases, low pressure or vacuum = high voltage.

You may be referring to the lowering of pressure in your fuel tank. As fuel is used, the pressure in the fuel tank drops to prevent vapours in the tank escaping to atmosphere. Ths is to comply with emission standards. The further you drive, the lower the pressure. When you remove the tank cap, air rushes in which makes you think it's coming out.

You are right. There are three pumps. It sounds like the transfer pump in the front tank is bad. The in tank pumps just supply the high pressure pump to keep it primed. You need the front pump.

change air filter.and fuel filter. replace plugs and wires.check tires air pressure.