Refueling is difficult

[mwillems]

Could be wrong. But the stop happens at the pump side of the equation. Car is the tank. Class dismissed.

The pump stops when the fuel does not flow smoothly down to the tank, and instead it backs up. As soon as the pump detects this fuel coming back, it shuts off. And that is the way it should be. What should NOT happen is that the fuel backs up instead of flowing smoothly down the line to the tank - and that's the car side of the equation.

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[Starship Enterprise]

Could be wrong. But the stop happens at the pump side of the equation. Car is the tank. Class dismissed.

This is our gas tank. It is commonly referred to as a "Saddle Tank".

It is closer to being 2 tanks with a hump in the middle that gas has to pass across. If there is too much back pressure from filling up too fast, the pump thinks the tank is full before the other side fills up. Some nozzles pump the gas faster than others or are more sensitive to back pressure, resulting in different experiences for everyone.

Literally a Mustang issue for decades.

Class dismissed.

 

[steveo1960]

Same here. Also same on wife’s 24 VW Atlas. The suggestions made by others work for me.

 

[AZ_Ryan]

This is our gas tank. It is commonly referred to as a "Saddle Tank".

It is closer to being 2 tanks with a hump in the middle that gas has to pass across. If there is too much back pressure from filling up too fast, the pump thinks the tank is full before the other side fills up. Some nozzles pump the gas faster than others or are more sensitive to back pressure, resulting in different experiences for everyone.

Literally a Mustang issue for decades.

Class dismissed.

No. Sorry. I never once experienced this on my last four mustangs. Nor have any of my friends. I maybe heard about this once or twice on the S197. Never on the S550 or S650. This is NOT a common issue. And it doesn't have anything to do with the gas tanks.

 

[Starship Enterprise]

No. Sorry. I never once experienced this on my last four mustangs. Nor have any of my friends. I maybe heard about this once or twice on the S197. Never on the S550 or S650. This is NOT a common issue. And it doesn't have anything to do with the gas tanks.

Did you ever Google the issue...... because if it never happened to you and 3 other people, it doesn't exist? and it's mentioned a LOT on 7G forums.

Now if you want to debate what's a "common" problem that's a gray area, but manufacturing design issues on the vent tube, and filler neck are documented. If the car didn't have the saddle tanks, the filler neck and vent tubes would not have been an issue.

There are many individual factors that lead to one "common" issue.

Whatever, I got better things to do than argue on the interwebs. what a friggin waste of time. No one is going to be on their deathbed wishing they said just one more thing on a message board.

Mustang Refueling Problems — Causes and Fixes
Many Mustang owners, especially those with S197 (2005–2017) and some earlier models, report difficult or repeated shut‑offs during refueling. This is often linked to fuel tank venting issues and filler neck design.

Common Causes

• Ventilation blockage: The fuel tank’s vent system must allow air to escape as fuel enters. In early models, the vent path can be obstructed by debris, a clogged hose, or a stuck vent valve S197 Mustang Forum.
• Filler neck design: Pre‑2008 models had a filler neck that didn’t vent the driver’s side of the tank well, causing backpressure when filling the second half S197 Mustang Forum.
• Clogged EVAP system: A blocked charcoal canister or vent hose can slow or stop fuel flow S197 Mustang Forum+1.
• Manufacturing defect: Ford acknowledged a defect in some S197 tanks (TSB 05‑15‑12) causing slow filling, especially above 1/4 tank RepairPal.
• Pump pressure differences: Station nozzle pressure can cause the Mustang’s fuel pump to detect backpressure and shut off Mustang7G.

Symptoms

• Pump shuts off every few seconds or stops mid‑fill.
• Fuel backs up into the filler neck instead of flowing smoothly to the tank Mustang7G.
• Problem worsens when fuel level is above 1/4 tank S197 Mustang Forum.

Workarounds and Fixes

• Turn the nozzle upside down or sideways — this can create a small gap to relieve backpressure Mustang7G.
• Trickle fill slowly — especially when the gauge is near 1/4 tank S197 Mustang Forum.
• Clean or replace the EVAP vent hose — check for debris, condensation, or blockages S197 Mustang Forum.
• Replace the vent valve or charcoal canister if clogged S197 Mustang Forum.
• Replace the filler neck hose — Ford’s TSB recommends this for affected models RepairPal.
• Upgrade to a later‑model tank — post‑May 2008 tanks have a vented filler neck S197 Mustang Forum.
• Empty the tank before filling — some owners avoid the problem entirely S197 Mustang Forum.

 

[Sofa King]

Could be wrong. But the stop happens at the pump side of the equation. Car is the tank. Class dismissed.

Not necessarily... a pinched or damaged fill neck could cause this issue.

 

[AZ_Ryan]

Did you ever Google the issue...... because if it never happened to you and 3 other people, it doesn't exist? and it's mentioned a LOT on 7G forums.

Now if you want to debate what's a "common" problem that's a gray area, but manufacturing design issues on the vent tube, and filler neck are documented. If the car didn't have the saddle tanks, the filler neck and vent tubes would not have been an issue.

There are many individual factors that lead to one "common" issue.

Whatever, I got better things to do than argue on the interwebs. what a friggin waste of time. No one is going to be on their deathbed wishing they said just one more thing on a message board.

Mustang Refueling Problems — Causes and Fixes
Many Mustang owners, especially those with S197 (2005–2017) and some earlier models, report difficult or repeated shut‑offs during refueling. This is often linked to fuel tank venting issues and filler neck design.

Common Causes

• Ventilation blockage: The fuel tank’s vent system must allow air to escape as fuel enters. In early models, the vent path can be obstructed by debris, a clogged hose, or a stuck vent valve S197 Mustang Forum.
• Filler neck design: Pre‑2008 models had a filler neck that didn’t vent the driver’s side of the tank well, causing backpressure when filling the second half S197 Mustang Forum.
• Clogged EVAP system: A blocked charcoal canister or vent hose can slow or stop fuel flow S197 Mustang Forum+1.
• Manufacturing defect: Ford acknowledged a defect in some S197 tanks (TSB 05‑15‑12) causing slow filling, especially above 1/4 tank RepairPal.
• Pump pressure differences: Station nozzle pressure can cause the Mustang’s fuel pump to detect backpressure and shut off Mustang7G.

Symptoms

• Pump shuts off every few seconds or stops mid‑fill.
• Fuel backs up into the filler neck instead of flowing smoothly to the tank Mustang7G.
• Problem worsens when fuel level is above 1/4 tank S197 Mustang Forum.

Workarounds and Fixes

• Turn the nozzle upside down or sideways — this can create a small gap to relieve backpressure Mustang7G.
• Trickle fill slowly — especially when the gauge is near 1/4 tank S197 Mustang Forum.
• Clean or replace the EVAP vent hose — check for debris, condensation, or blockages S197 Mustang Forum.
• Replace the vent valve or charcoal canister if clogged S197 Mustang Forum.
• Replace the filler neck hose — Ford’s TSB recommends this for affected models RepairPal.
• Upgrade to a later‑model tank — post‑May 2008 tanks have a vented filler neck S197 Mustang Forum.
• Empty the tank before filling — some owners avoid the problem entirely S197 Mustang Forum.

Im on here all the time and ive never heard of anyone else with a fueling problem. Google isnt gospel. And I could care less about the S197 as thats not relevant. Did you read all the posts above saying they've never had an issue? Its not just me and three other people lol.

What I dont think you realize is different states have different pump and nozzles configurations based on state law for spillage and overfill. California is notorious for its pump fueling issues requiring people to turn the nozzles sideways or upside down on certian vehicles.

What im saying is, yes, some people in all kinds of cars have issues, but its the pump not the car. Many people who have had issues go to another station or brand and dont have issues.

 

[Starship Enterprise]

Yes it's the pump. That pump can work just fine on one car, but pull a car up with a saddle tank or faulty filler neck, or clogged vent valve, issues occur.

Other pumps with less pressure don't reveal underlying issues with a car's tank system. A car with no tank filling issues can go to any pump with no problem.

 

[mwillems]

Yes it's the pump. That pump can work just fine on one car, but pull a car up with a saddle tank or faulty filler neck, or clogged vent valve, issues occur.

Other pumps with less pressure don't reveal underlying issues with a car's tank system. A car with no tank filling issues can go to any pump with no problem.

Ah, but I was very careful NOT to squeeze the trigger hard. In other words, I kept the flow to a minimum to see if that made a difference. And it did not.

I’ll try other pumps. But this gas station is my regular one, and it’s never given me problems with any other car.

 

[Starship Enterprise]

Exactly!

 

[AZ_Ryan]

Yes it's the pump. That pump can work just fine on one car, but pull a car up with a saddle tank or faulty filler neck, or clogged vent valve, issues occur.

Other pumps with less pressure don't reveal underlying issues with a car's tank system. A car with no tank filling issues can go to any pump with no problem.

I would love to see your data in this.

 

[Ken H.]

JFC: Some of these rude replies... WTF?!?

This is a common fueling problem with the Mustang for literally decades. My 06 would click off while fueling if the nozzle pressure is too high. every station is different, and pressure can differ at every pump.

Holding the nozzle upside down works because I believe it leaves a gap which allows back pressure to escape.

What he said. The definitive answer!

 

[Ken H.]

Ah, but I was very careful NOT to squeeze the trigger hard. In other words, I kept the flow to a minimum to see if that made a difference. And it did not.

I’ll try other pumps. But this gas station is my regular one, and it’s never given me problems with any other car.

Keep your regular station. Turn the nozzle. Let’s move on. Everyone is happy. Beers on me

 

[Zig]

. Everyone is happy. Beers on me

but liquor is quicker

 

[Starship Enterprise]

I would love to see your data in this.

There's TSB's on it.

https://repairpal.com/problem/ford/mustang/hard-to-fill-up-with-fuel-500

https://themustangsource.com/forums...low-fill-548463/tsb07-21-12-213357d1621361008

The 2nd link shows an actual TSB for the S197. it says the TSB addresses the issue but says it only minimizes the issue. A TSB reflects hard data.

Yet forums talk about having problems filling for the 550/650 ad nauseum. So much that this forum linked to 3 other threads about it.

https://themustangsource.com/forums/f739/trouble-filling-gas-tank-549366/

What are we even arguing here? The people having problems are imagining it? At this point blaming the pumps is only looking at half the argument.

Personal experience. on my 06 GT I had filling click-off issues happen from time to time.....AT THE SAME PUMP I ALWAYS USE.

So the argument is that it's the pump not the car? My argument is some pumps just point out the inherent weak points in the car's fuel filling system. I haven't experienced it yet in my 2025 FWIW.

Anyway, I have 2 new kittens to play with. Brothers I couldn't split up. So here's a palate cleanser.

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