09ssbeast

I have a 2009 cobalt ss sedan. Every time i try to fill my car the gas pump clicks off every dollar or if i fill it up too fast. Mind you this is all the time. it takes me 10 min to fill my tank because the filler neck thinks the gas tank is full. what could be the problem? I already replaced the fuel pressure sensor

exninja

iTrader: (1)

obstruction in the filler neck?
are you using the pump right?
Does it overflow if you keep filling when it clicks off?

T-fog

^^ this
Have you tried not pressing the handle all the way down? Maybe the vent valve is starting to fail and can't keep up as your filling ? Or you could pull the nozzle out a little as you fill your car see if that works as well?

Just to be clear you replaced the pressure sensor right?

I want to say its a vent valve issue.

tomj77

iTrader: (2)

Had same issue, tried replacing solenoid on manifold and in canister, did nothing, so I ended up up replacing the entire vapor canister and the tank pressure sensor that is in the canister, that fixed it

09ssbeast

^^ this
Have you tried not pressing the handle all the way down? Maybe the vent valve is starting to fail and can't keep up as your filling ? Or you could pull the nozzle out a little as you fill your car see if that works as well?

Just to be clear you replaced the pressure sensor right?

I want to say its a vent valve issue."



Even if i dont press the handle all the way down it clicks off after a dollar or two. There is not fuel over flowing either. Its frustrating that it takes 10-12 min to fill a 12 gallon tank -___-.

The sensor on the manifold was also replaced. So i guess the next thing is to replace the charcoal canister???

Slowbalt2000

iTrader: (1)

try just pulling the handle out a little bit so there is a gap between it and the filler neck, this should allow some of the excess pressure to escape

blueLNFftw

iTrader: (16)

It is nothing like you guys think.


OP you need a new vent solenoid. The most common one to fail is the one on the very front of the intake manifold. Do that one first. If the problem persists than you need to replace the one on the tank as well. They are about $25 a piece.

Slowbalt2000

iTrader: (1)

the one in the engine bay is called a purge solenoid and is normally closed. that shouldnt affect the way the tank fills.

blueLNFftw

iTrader: (16)

It does though. Seen it happen.

Slowbalt2000

iTrader: (1)

OP use a code reader to check and see if you have any codes, go from there. dont just throw parts at it

umrdyldo

iTrader: (1)

I completely agree. either solenoid can cause this issue. The evap purge on the manifold is a much more common failure point.

Slowbalt2000

iTrader: (1)

describe to me then how that solenoid can affect the fill of the gas tank

09ssbeast

Even if i pull the handle out a bit it doesn't change anything.

09ssbeast

The code is a P0451 EVAP emissions control system. Just plugged it in yesterday

Slowbalt2000

iTrader: (1)

sensor measures air pressure or vacuum in the evaporative emission (EVAP) system. The engine control module (ECM) supplies a 5-volt reference and a low reference circuit to the FTP sensor. The FTP sensor signal voltage varies depending on EVAP system pressure or vacuum. The ECM also uses this FTP signal to determine atmospheric pressure for use in the engine-off small leak test, DTC P0442. Before using this signal as an atmospheric reference it must first be re-zeroed. The sensor performance test includes checks for sudden changes in pressure or signal oscillation and a pressure range check.

This turbocharged engine is equipped with a one way flow check valve that prevents boost pressure form entering the purge line and EVAP system.

Conditions for Running the DTC

P0450
The engine is running.
The estimated ambient air temperature is warmer than -7°C (+19.4°F).
The EVAP canister vent valve has been open for more than 3 seconds.
The vehicle speed is less than 29 km/h (18 mph).
DTC P0450 runs continuously when the above conditions have been met.
P0451 - Part 1
The engine is running.
The vehicle speed is greater than 0 km/h (0 mph).
The ambient pressure is greater than 68 kPa.
The estimated ambient air temperature is warmer than -7°C (+19.4°F).
The fuel level is between 12-88 percent.
DTC P0451 runs continuously when the above conditions have been met.
P0451 - Part 2
The EVAP canister purge solenoid valve is closed and the EVAP canister vent solenoid valve is open.
The vehicle speed is between 10-75 km/h (6-46 mph).
The time since engine start is greater than 450 seconds.
DTC P0451 runs whenever the above conditions have been met.
P0452 and P0453
The engine is running.
DTCs P0452 and P0453 run continuously when the above condition has been met.
Conditions for Setting the DTC

P0450

There are sudden changes in fuel tank pressure greater than a calibrated amount for up to 30 seconds.

P0451 - Part 1

The FTP is greater than 7 in H2O or less than -16 in H2O for more than 4 seconds.

P0451 - Part 2

The fuel tank pressure changed 0.68 kPa compared to a reference value stored at the last cold start.

P0452

The FTP sensor voltage is less than 0.1 volt for more than 4 seconds continuously or 50 seconds cumulative.

P0453

The FTP sensor voltage is more than 4.85 volts for more than 4 seconds continuously or 50 seconds cumulative.

Action Taken When the DTC Sets

DTCs P0450, P0451, P0452 and P0453 are Type B DTCs.

Conditions for Clearing the MIL/DTC

DTCs P0450, P0451, P0452 and P0453 are Type B DTCs.

Diagnostic Aids

P0450 and P0451
A restriction in the EVAP canister or vent lines could prevent fuel vapor pressure from bleeding off fast enough. If the vent system cannot bleed off pressure fast enough, the re-zero procedure may not complete successfully, which could cause this code to set.
Ensure that the reference port on the FTP sensor is unobstructed.
An FTP sensor that is skewed or does not have a linear transition from low to high may cause this code to set. Scan tool output controls, snapshot, and plot functions can help detect erratic sensor response. To test the sensor signal under vacuum conditions, use the Quick Snapshot and the Purge/Seal functions to capture data while commanding purge to 20 percent, then plot the data to look for erratic sensor operation. A similar test can be done for the pressure side of the sensor operation by applying pressure with the J 41413-200 while taking a snapshot.

Slowbalt2000

iTrader: (1)

Ignition ON, observe the scan tool fuel tank pressure (FTP) sensor parameter. The reading should be between 1.3-1.7 volts with the fuel cap removed, and change with fuel tank pressure. Increasing pressure causes decreasing voltage, decreasing pressure causes increasing voltage.

Circuit/System Testing

Ignition OFF, disconnect the harness connector at the FTP sensor.
Ignition OFF, test for less than 5 ohms between the low reference circuit terminal 2 and ground.
¤ If greater than the specified range, test the low reference circuit for an open/high resistance. If the circuit tests normal, replace the control module.
Ignition ON, test for 4.8-5.2 volts between the 5-volt reference circuit terminal 3 and ground.
¤ If less than the specified range, test the 5-volt reference circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the control module.
¤ If greater than the specified range, test the 5-volt reference circuit for a short to voltage. If the circuit tests normal, replace the control module.
Verify the scan tool FTP sensor parameter is less than 0.2 volt.
¤ If greater than the specified range, test the signal circuit terminal 1 for a short to voltage. If the circuit tests normal, replace the control module.
Install a 3A fused jumper wire between the signal circuit terminal 1 and the 5-volt reference circuit terminal 3. Verify the scan tool FTP sensor parameter is greater than 4.8 volts.
¤ If less than the specified range, test the signal circuit for short to ground or an open/high resistance. If the circuit tests normal, replace the control module.
If all circuits test normal, test or replace the FTP sensor.

firehawk618

iTrader: (2)

I agree. Please explain how the front EVAP solenoid can cause the problem the OP is describing.

Impossible.

Slowbalt2000

iTrader: (1)

based on the description of the code it seems like OP has a clogged carbon canister and possibly a bad fuel tank pressure sensor/wiring

09ssbeast

UPDATE on my car. There were a **** ton of spider webs in the Charcoal canister. Filled my tank up after it was cleaned out with no problems. But now yesterday when i went to fill up same F****** problem but not as bad. What else could it be

07blackg5

iTrader: (8)

if the canister was clogged up that bad, there is a good possibility the lines are as well

09ssbeast

my mechanic made sure the line were clear by using his air gun.

09ssbeast

UPDATE UPDATE UPDATE!!!!!!!!!!!!!!!! So the problem with the fueling was a tube in my filler neck. I guess someone tried to steal gas outta my tank and in the process the rubber hose got stuck in the valve that prevents gas from getting stolen. Totally blanking on the name of the valve. But anyways there was a 12-14 inch rubber tube stuck in there. That is why it took so long to fill up. My mechanic took it out and no problems after that. Me and him were completely shocked.

exninja

iTrader: (1)

What do I win?

T-Man

iTrader: (3)

A NEW CAR!!!

exninja

iTrader: (1)

Yuussssssssssssssssss