Why Your Car Won’t Start After Getting Gas: Common Causes and Solutions

You pop into a gas station to fill up your tank for the week; you top it off, hop back into the driver’s seat, turn the key, and the car won’t start or struggles futilely to turn over. This can be a deeply embarrassing moment if there are people in line behind you.

While you pop the car in neutral to push it out of the way, you will wonder why your car struggles to start after getting a gas fill-up.

The most likely culprit in a newer vehicle is the EVAP purge valve is stuck open. This is part of your car’s emissions control system and helps to trap potentially harmful fuel vapors from escaping into the atmosphere.

Though it’s not the only thing that might be keeping your car from starting after getting gas, to ferret out the problem and determine if there’s anything you can do or if it’s time to call the tow truck, we’ll need to zoom in on some of the most common reasons why your car won’t start after refueling.

Understanding the Reasons Why Your Car Won’t Start After a Gas Fill-up

A malfunction in the car’s emissions control system is one of the more common reasons why a newer car doesn’t start after getting gas. However, there are certainly some other nuts and bolts reasons that could be afoot that have nothing to do with the EVAP purge valve.

1. An EVAP Purge Valve Problem

A lot of newer cars have an emissions control system that includes a special EVAP purge control valve. Suppose it gets stuck open, and you fill your tank all the way full. In that case, the valve could let fuel into the intake manifold, which makes it impossible for the car’s ECU to get the fuel/air mixture right when you try to turn it over.

In some ways, this is very similar to flooding an old-fashioned carbureted engine. After a few minutes, the excess fuel in the manifold will dissipate, and hopefully, the car should start again like normal.

How To Fix

Even if you get the car started again after a few minutes, this problem will likely persist and need to be repaired by a mechanic.

The cost to have a mechanic repair a stuck EVAP purge control valve ranges between $150 to $300.

2. Deposits or Water in the Fuel Tank

In an older vehicle tank deposits, varnish and water that normally sits in the tank can be agitated with the onrush of fresh fuel. This can sometimes send deposits or potentially contaminated water close to the intake for the fuel line. You turn the key, and the contamination is momentarily sucked in, resulting in your car’s engine not turning over after filling up.

From there, varnish and tank deposits can severely clog the fuel filter or prevent the fuel pump from delivering the necessary flow of fuel to the engine. In the case of water in the gas tank, it can get passed through the fuel system to the fuel rail, where it can wreak havoc with the pistons or cause hydro lock in the cylinders.

Any one of these tank contamination problems can easily cause starting problems after getting gas. This is not the sort of thing that will improve with time, and you’ll need a tow truck to take your car to a mechanic to have the tank purged and the fuel system repaired.

How Much Dose It Cost To Fix?

The cost to have a fuel tank purged varies from $50 to $150. The cost to replace a clogged fuel filter ranges from $75 to $150. The cost to replace a fuel pump ranges from $250 to $650.

The cost to fix a case of hydro lock will depend on the damage to the engine and fuel system, but averages around $3,000.

3. Air in the Fuel Line

Gas pump nozzles are supposed to be able to tell when the fuel in the tank is full and shut off automatically long before the fuel level has a chance to ascend the tank nozzle. However, they’re not perfect and rarely well-maintained.

When this happens, it can cause a small volume of gasoline to momentarily siphon out of the tank, which might be able to draw air into the fuel line. This affects fuel delivery and the fuel system’s pressure, causing the car not to start after refueling.

How to Fix Air in the Fuel Line

To get the air out completely out of the fuel line, you’ll need to have a mechanic bleed the fuel system. This costs around $100 to $150.

Though there’s also the concern that there’s an air fault somewhere in the fuel rail or the fuel lines, which might also need to be repaired to prevent the problem from happening again.

4. A Clogged Air Filter or Air Intake

A badly clogged air filter or air intake from something like an unknown mouse nest could also cause the car to not start after getting gas. In a scenario like this, the obstruction might have been poised to clog the air intake before you stopped the car.

When you go to start it, the engine cycle drawing in more air is just enough to finally pull it into the intake completely. This is even more likely to be an issue if you recently had the car stored for a while.

If you open up the air filter, you might be able to see the clog in the air intake and remove it. Though if any debris goes further in, the wisest move is to have the car towed to a mechanic. They can clean out the air intake and test all other related components, like the throttle body, to ensure nothing is getting drawn into the engine. This usually costs around $110 to $220.

5. A Clogged Fuel Filter

Fuel filters naturally clog over time, and a severely clogged fuel filter can cause your car to not start after a gas fill-up, especially if you’ve gone more than 30,000 to 45,000 miles without having the fuel filter replaced. It’s even more likely to be a problem if you stored your car or didn’t drive it for a month or more before getting gas.

In a case like this, you might notice the engine feeling down on power, idling rough, and being hard to start. Then you get some bad gas, or the new fuel in the system sends a clog of tank deposits into the fuel filter, impeding the necessary fuel flow to get the car to start normally.

How To fix

In a scenario like this, you must have the car towed to a mechanic or perhaps a rapid oil change shop. If you’re lucky, it’s just that the fuel filter itself needs to be replaced, and the fuel pump is operating fine.

Though if your car sat in storage for a few months before the problem started, you shouldn’t be surprised if the mechanic also recommends purging the fuel tank as well.

The cost to replace a clogged fuel filter ranges from $75 to $150.

6. A Bad Fuel Pump

A bad fuel pump from a severely clogged fuel filter and/or tank deposits frequently being sucked into the fuel system can cause a car to not start after filling the gas tank. When a failing fuel pump finally dies, it can happen surprisingly fast. Sometimes it just needs a minor incident, like contaminants from bad gas getting sucked into the fuel system, to kill the fuel pump finally.

Again, you likely would have noticed the steady decline in performance, hard starting, and rough idle of a failing fuel pressure before the fuel pump died. Usually, the death knell right before a fuel pump goes out is a mechanical whine or buzzing noise back by the fuel tank.

How To Fix

If it is a bad fuel pump that caused your car to not start after getting gas, you’ll need to get the car towed to a mechanic. Replacing a bad fuel pump is something that is better left to the professionals to repair safely.

The cost to replace a fuel pump ranges from $250 to $650.

7. A Bad Fuel Pressure Regulator

When a bad fuel pressure regulator has a point of failure where the internal bladder completely gives out, the regulator might have been failing and/or struggling to maintain a consistent flow of fuel to the fuel rail. When you turn the engine off to fuel up and start it again, the rapid changes in pressure can cause the regulator’s bladder to finally fail, completely preventing the engine from starting.

How To Fix

The signs of a bad fuel pressure regulator failing usually have you suspicious by the time the car refuses to start. Though when it goes, the only real option is to have it replaced. If you’re a capable DIY mechanic, you might be able to do this on your own. However, there’s no shame in having a professional mechanic handle the fuel pressure regulator replacement.

The part cost for a new fuel pressure regulator averages around $125 to $175 and will take an hour or two of your time to replace. 

If your fuel pressure regulator is integrated into the fuel pump assembly, or you feel that replacing it is outside your skills, a mechanic will charge you between $300 to $500 for parts and labor.

8. Dead Battery or Bad Alternator

A dead battery can prevent a car from starting at any time. Though when a car doesn’t start after getting gas, after only being shut off for a few minutes, it’s usually that the alternator has died or is dying and hasn’t been sufficiently charging the battery for a while.

In a case like this, the car likely would have died on you at a stall at some stop lights when the battery would have gone completely flat. It’s just the draw of current needed to start an engine is so high that the problem revealed itself at the pumps once the car was shut off.

How To Fix

If your car doesn’t start after getting gas due to a dead battery with a bad alternator, you’ll likely need to get the car towed home or to a mechanic. If you’re lucky, it’s just a dead alternator, which a modestly accomplished DIY mechanic can do on their own. Otherwise, you might need a new battery and a new alternator.

Depending on the size and model, a replacement alternator costs $125 to $250.

The cost of having a mechanic replace your alternator ranges from $225 to $400.

9. A Bad Starter Motor

If your car won’t start after getting gas and has been struggling to start lately, a bad starter motor might be to blame. This might not have anything to do with the fuel system or clogs in the fuel system that caused hard starting in the past and worn down the starter motor to the point that it finally died.

In most of these cases, the problem is that one or multiple teeth in the starter motor’s Bendix gear have broken off or worn down. Then there simply isn’t enough contact between the starter motor and the flywheel to get the engine to turn off. This can be compounded by a clogged fuel filter or dying fuel pump that also struggles to deliver the fuel needed to support vigorous internal combustion.

How To Fix

If a bad starter is the reason your car won’t start after getting gas, you might be able to tap the starter with a mallet to get it to engage properly. You might get lucky, and it will restart the car after 5 to 10 minutes. However, cranking relentlessly is more likely to cause further damage and strain the battery.

If you’re a modestly capable DIY mechanic, you might be able to replace the bad starter yourself. Though most people will have the car towed to a mechanic to repair it professionally.

The cost to have a mechanic rebuild a car’s starter ranges from $150 to $650, with professional installation.

The cost of a new starter motor ranges from $80 to $350 before installation.

10. Bad Spark Plugs or Coils

Bad spark plugs and/or multiple failing ignition coils could be the reason your car won’t start after getting gas. In a case like this, the fuel system delivers the fuel necessary to restart the car, but the spark isn’t occurring at the point of compression, and the fuel goes unburned.

In a scenario like this, you likely have multiple bad coils and/or multiple fouled spark plugs. When multiple cylinders don’t fire, there isn’t enough internal combustion happening in the correct sequence to get the engine to turn over and stay running. If the multiple failed plugs and coils happen to be first in the firing sequence, it could potentially even flood the cylinders preventing the car from starting.

Though this is the sort of problem that doesn’t usually pop up on you out of nowhere, chances are good the car has been giving off signs of bad plugs and coils for a while, and it finally reached the point of failure. Especially if your car has gone more than 75,000 to 100,000 miles without a tune-up.

How To Fix

If it’s just multiple fouled spark plugs that are causing the car to not start after getting gas, and the engine is flooded, you should try to wait 5 to 10 minutes to let the unburned fuel dissipate. Then attempt to start the car again. If it still doesn’t turn over, then you likely need to get a tow.

If you’re a reasonably accomplished DIY mechanic, you can probably replace your own spark plugs and probably even replace bad ignition coils. However, this can be a labor-intensive job that could eat a whole weekend with diagnostics and repairs. So, there’s no shame in having the car towed to a mechanic to have it professionally repaired.

The cost to replace spark plugs yourself is usually $20 to $25 per plug, not counting essential tools like a torque wrench.

The cost to have a mechanic replace your spark plugs adds an extra $125 to $250 in labor costs.

A full tune-up by a mechanic range from $250 to $750.

11. A Bad Crankshaft Position Sensor

Your engine’s crankshaft position sensor plays a critical role in helping the ECU coordinate the engine’s timing. If the sensor has been failing, the ECU might get the timing wrong to the point where the car can’t start after a momentary stop, like getting gas. This is a problem that has nothing to do with the act of getting gas. It’s likely a gremlin that’s been lurking and struck at the worst possible time. 

How To Fix

If the ECU turns on the Check Engine Light, and it’s a bad crankshaft position sensor will throw a code P0335 or P0340.

This is a relatively inexpensive fix; a mechanic can usually replace a crankshaft position sensor for $125 to $300. The part itself usually costs around $50 to $95, and the rest of the cost is labor fees.

12. An Ignition Key Security System Problem

Many modern-day inboard car security systems have a sensor that reads an RF signal from the key fob. If there’s a problem with the fob or the internal battery dies, the car will continue to run until you stop the engine. When you try to turn the key again, the car’s computer looks for the RF signal. If it doesn’t find it, then it won’t engage the ignition system even when you turn the key in earnest.

How To Fix

I’ve had this happen to me before. Usually, you can go back home, get the spare key, and the car will read the RF signal to turn over when you turn the key or press the start button. If this doesn’t work, then you’ll need to get the car towed to a mechanic, who will have the right tools to reset the system.

13. A Worn Out Key or Bad Tumblers

If your car uses a physical key, and it’s a few years old, the contours on the key can be worn down to the point where they don’t always match the tumblers inside the ignition cylinder of the steering column. It’s also possible to damage one of the tumbler pins if you once put the wrong key into the ignition system.

How To Fix

I’ve had this problem before, and usually, you can just jiggle the key a few times while pulling to the right on the steering wheel. With a little bit of luck, the tumblers will accept every millimeter of the key, and the car will start again.

If not, you might want to try using a lesser-used spare key, which will seat more firmly with the tumblers in the ignition cylinder. Otherwise, you’ll need to tow the car to a mechanic who will need to repair the steering column.

How to Fix a Car That Won’t Start After Filling the Gas Tank

Right off the bat, you need to put the transmission in neutral, then see if you can recruit a good Samaritan to help you push the car into a nearby parking spot. This will get you out of the way of anyone else who wants to get gas and keep you in the good graces of the gas station attendant.

In a perfect world, you would park the car with the drive tires facing toward the parking lot or the street. This will make it much easier for the tow truck to hook up quickly, should you need to tow the car to a mechanic.

Once it’s parked and safely out of the way, you can use the following steps to try to diagnose the problem.

Can Bad Gas Cause My Car to Not Start?

Filling up with bad gas from something like a low-end, rural gas station won’t immediately prevent your car from starting. The car should still have several minutes of good fuel remaining in the fuel lines from when you shut it off at the pump.

If you put your car in storage for more than a month or so without a fuel stabilizer in the tank, the gas can degrade. This can allow moisture, tank varnish, and other deposits into the fuel system.

It’s also possible for fresh fuel going into the tank to loosen deposits left in storage, which then get sucked into the fuel system preventing properly pressurized fuel from making it to the fuel injectors. In a scenario like this, bad gas lingering in the tank could cause the car to not start after getting gas.

Don’t get stranded

If your car stalls after filling up with gasoline, the most likely culprit is a stuck-open EVAP purge valve. If you’re lucky, a 10-minute wait might be enough to get the car started again. Then you’ll need to call a mechanic to have it repaired properly or risk another incident.

If you suspect it’s a dead battery caused by a bad alternator, and you can get the car started again, you’ll need to drive immediately to a mechanic or an auto parts store to have both the battery and the alternator tested. 

A bad starter motor, faulty ignition coils, or fouled spark plugs could also be the reason why your car won’t start again after getting gas, but these aren’t things you can fix in a service station parking lot and you’ll need to get the car towed.