Car Won’t Start After Getting Gas (12 Reasons Why)

If there’s anything more annoying than a problematic car, it is a car that will not start. When the tank is full and the fuel gauge is not miscalibrated, there should be no reason a car won’t start after getting gas, right? Well, let this article enlighten you on why that is not quite the case.

Usually, a car stalls after getting gas when air, fuel, and spark are delivered out of proper proportion to the engine. There could be a bad ignition coil, leaking valve, or a clogged air/fuel filter. In some cases, the problem is due to a faulty wire connector or system component.

Here are 12 of the most common reasons a car won’t start after getting gas:

  1. Dead or corroded battery
  2. Broken alternator
  3. Bad starter motor or circuit
  4. Lack of spark
  5. Non-working key fob
  6. Unaddressed trouble codes
  7. Restricted fuel filters/injectors
  8. Damaged fuel pump
  9. Jumped or skipped timing belt
  10. Stuck purge control valve
  11. Faulty security system
  12. Wheel lock

For your engine to get ignition, fuel delivery, and compression right, all components revolving around these systems must be in a functional, healthy condition. If one performs amiss, it creates a domino effect that carries over to other systems in your vehicle. It is, therefore, crucial to adhere to scheduled maintenance and proper care for your wheeler. More so, get to learn each of the above causes and their respective fixes in this guide.

Person Starting Car and Turning Key Ignition

Reasons a Car Won’t Start After Getting Gas 

1. Dead or Corroded Battery

If your car won’t start right away after getting gas or the engine cranks slowly, you may be dealing with a battery that is discharged or expired or one that has loose/corroded battery terminals. Especially when purchasing a secondhand vehicle, it is pretty easy to forget about the battery’s shelf life. Often, owners only check on the usable life of their battery once it shows signs of having trouble holding a charge or starting issues begin to occur.

Behaviors resulting in a voltage drop include leaving the lights on for extended periods and running the battery completely empty. It is never advisable to do the latter as an emptied-out battery will not allow your engine to roll over and your alternator to start charging it. More so, it can be troublesome looking for another car in the middle of the road to jump-start your vehicle.

The typical battery lifespan is between three and six years. So, if you suspect your battery is why your car won’t start after getting gas, you can rule it out by boosting the battery and testing the alternator to see if it charges at more than 12V. Doing this would be hitting two birds with one stone – with the outcome pointing to a dead battery or faulty alternator. Not to mention it eliminates unwarranted battery replacements without working around the battery or cleaning its posts first.

2. Broken Alternator

The alternator (view on Amazon) is usually the second suspect when the battery checks out after testing. And rightfully so, as it is the component that generates electricity and stores excess electrical power in your battery, ensuring your engine will fire right up the next time you need it to. It is also what helps power up your headlights, wipers, radio, window defroster, heater, and heated seats. Simply put, it is your vehicle’s charging system.

While it makes sense for a discharged battery to be associated with a defective alternator, you should not jump to this conclusion straight away. If the alternator is acting up and your battery is not getting charged, then you might want to check for a worn or slipping accessory drive belt first. Watch out for a slow cranking starter, dimming headlights, and a warning light, too, as they indicate a poor alternator output. Depending on your car’s make and model, its instrument panel may or may not come with an alternator gauge. Either way, you may want to test the alternator with a proper gauge to see if it shows approximately 14 volts.

3. Bad Starter Motor or Circuit

As its name suggests, a starter motor helps physically turn your engine over and get it to fire. And out of all the items in this list, it is probably one of the easier causes to detect, as problems with the starter motor are usually accompanied by clicking sounds when turning your keys in the ignition. Because the starter motor depends on your car battery to supply power to start the engine, it may give the illusion of a weak battery symptom. If the starter does not turn altogether, it may have a shot relay or solenoid, or the ignition switch may be at fault.

When cranking the engine, owners usually hear a click or series of clicks, which would indicate that the starter motor is not engaging with the flywheel. This occurrence is due to the loss of teeth on your starter’s drive gear or the engine’s flywheel. In whichever case, your car won’t start after filling with gas if it has a broken starter motor. You may need a starter replacement, which can cost up to $350.

4. Lack of Spark

The spark plug ignites the air-fuel mixture and fuel in your engine. Without a properly working plug or timed spark, your vehicle suffers engine misfiring and can become inoperable. However, it is important to note that bad spark plugs are not the only culprit behind the lack of spark. Cracked porcelain insulators, worn electrodes, a flooded engine, and problems with the ignition module, circuit, or switch are to blame, too. Also, plugs degrade with age.

Use an adjustable spark tester – one that can test for 40KV, 30KV, and 10KV spark – to examine the proper arc of each spark plug wire or ignition coil. Also, visually inspect the distributor cap (if applicable) for looseness, moisture, cracks, carbon traces, or other types of damage. Ensure all cylinders are firing with the right timing with the use of a timing light – this is quite useful when diagnosing issues with the timing system.

But if you think the problem is engine flooding (indicated by a strong fuel odor under the hood) and not the spark plugs, remove the plugs, dry them out, replace them, and start the engine again to see if it turns over completely. If it still does not and all other engine and ignition components have checked out, then take your vehicle to the local mechanic.

5. Non-Working Key Fob

While proximity keys and starting devices have made it convenient to start vehicles, they are also among the top reasons why your car won’t start after getting gas. Furthermore, key fobs are known to cause havoc for owners, especially when they go out unexpectedly or in dire situations. Replacing the key fob battery is very easy to do. Looking for it when it goes missing is a different story. However, things can get pretty technical and tedious – like resolving computer trouble codes and involving a car locksmith – if you require more than just a battery replacement to get your engine running.

6. Unaddressed Trouble Codes

Present-day vehicles have a computer (a.k.a. PCM, ECM, ECU, etc.) that controls multiples sensors and actuators – part of which is responsible for enabling your car to start. If these sensors receive false or insufficient input, they can prevent the engine from starting. So, even if the check engine light does not come on, scan for trouble codes using a Foxwell OBDII NT624 Elite Diagnostic Scan Tool (view on Amazon) and resolve them, if any, before proceeding with other troubleshooting steps. Here is a list of sensors whose trouble codes you should watch out for:

  • Crankshaft Position Sensor (CKP)
  • Camshaft Position Sensor (CPS)
  • Throttle Position Sensor (TPS) – monitors the throttle valve position and helps the computer regulate air-fuel mixture according to engine requirements
  • The Manifold Absolute Pressure (MAP) – compares barometric/atmospheric pressure to the intake manifold vacuum
  • Mass Airflow (MAF) – tells the computer the amount/density of air entering the engine; degree of usage, dirt or foreign matter can prevent the sensor from working
  • Engine Coolant Temperature (ECT) – determines how much fuel the engine needs; when bad, it can affect ignition timing and operation of the transmission or cooling fan

7. Restricted Fuel Filters/Injectors

There are several ways to go about verifying if this is why your car won’t start after getting gas, and all are reliant on the symptoms that come with the issue. If your engine does not start at all, look into the other items in this list. But if your engine runs momentarily then dies, then it could be that fuel is not getting to the cylinders. This could be due to several factors – one of them being debris collected in the tank and become engine sludge, preventing fuel pressure buildup. Running your vehicle to empty is another contributor to clogging your fuel filter. Depending on how poorly your engine reacts when you turn on the ignition, you may need to check other components of your car’s fuel delivery system.

For fuel-injected vehicles, there should be a Schrader valve on the fuel line going to the injectors. You can do a quick test to ascertain the cause of your no-start issue via this valve with a screwdriver after turning the ignition on and priming the line with fuel. Fuel should squirt out when pressing on this valve. Getting so much as a dribble of or no fuel would confirm a problem with one of the three – filters/injectors, fuel pump, or fuel pressure regulator. Additional steps such as comparing fuel pressure with manufacturer specs and using a nod light to test if injectors are receiving the pulse signal from the computer will help you close in on the culprit.

8. Damaged Fuel Pump

Appropriate fuel pressure is crucial for your car to start, especially if it has a fuel-injected engine, and this is made possible by the fuel pump. It keeps fuel moving from the tank into the combustion chamber of your engine and runs continuously any time the engine is running (including when the car is idling). Essentially, the pump has more mileage compared to that of your car and, as such, is prone to fail over time. And when the fuel pump weakens or gets damaged, your vehicle ends up with nothing to run on – hence, it will not start even if your gas tank is filled to the brim.

Some owners would ‘ear out’ or listen for a buzz or sputter a short while after turning the ignition on. These same folks assume the fuel pump is dead if they hear nothing inside the vehicle or back by the filler neck of the fuel tank. While this process has some truth, it does not apply to all kinds of vehicles as some do not have an audible buzz or in-tank sound, while others have fuel pumps that will flow only while the car is cranking. In both instances, the ‘ear out’ method may prove difficult. The same goes for diagnosing and repairing a broken fuel pump, which is best left to experts.

Note: Certain vehicles like Ford models have an inertia switch. This switch automatically cuts power to the fuel pump after a car is involved in a crash or accident, preventing it from catching on fire. If you have this on your wheeler and think that it was activated by mistake, you can manually pop the button back in – this should allow your car to start right up.

9. Jumped or Skipped Timing Belt

By definition, a timing belt/chain syncs rotation between the camshaft and crankshaft. But like other components, it is subject to wear or damage over time and after tons of mileage (and excessive oil saturation). A worn-out belt can skip a cog or two and cause an air leak, ultimately leading to a poor or non-existent combustion. Worst-case scenario, a bad timing belt can result in disastrous engine damage, warranting the entire power mill to be replaced.

While removing the timing cover and visually inspecting the belt/chain condition is relatively easy for specific vehicles, the reverse is true for most cars. Replacing a bad timing belt requires a certain level of mechanical skill due to the top-end work required. Performing a leak-down test, checking compression pressure, and inspecting the pistons and valves with a borescope make up the easy part. Putting back the timing belt in the correct position afterward is not as convenient.

Note: The power booster vacuum hose, a blown head or intake manifold gasket, and any other main vacuum hose are other areas in your vehicle where an air leak could take place.

Car Engine Timing Belt

10. Stuck Purge Control Valve

The purge valve (otherwise known as exhaust gas recirculation) is part of the evaporative emissions control system that helps lower engine temperature and harmful emissions. Normally, this valve stores harmful fuel vapor into a canister until it routes it into the intake manifold for burning. When this valve gets stuck open, the excess emissions collect inside the power mill, causing engine flooding before start-up. When this happens, a driver would need to depress the gas pedal to open up the throttle body and bring in extra air required for combustion.

The best fix for this problem is simply replacing the vapor canister purge control valve. To gain access to it, you will need to go through the air filter housing (view on Amazon), loosen the vacuum hose clamp, remove the air intake tube from the throttle body, and loosen the fuel hose connected to the purge valve or canister vent valve.

Exercise caution when performing this procedure, as detaching the vacuum tubing from the defective valve can prove difficult and sometimes get torn in the process. They also recommend replacing the purge solenoid by the EVAP tank while you are it. There is no need to reinstall a new purge valve – you will need only to reverse the steps taken to get to the old one. Make sure to consult your owner’s manual on how to test the valve.

11. Faulty Security System

Depending on your vehicle, it may have an engine immobilizer as part of its anti-theft security system. If this system becomes faulty or its chip fails, it may erroneously disable your car’s fuel or ignition system. If you’re unsure how to address the situation, a security warning on your dash can help point you in the right direction.

Running a diagnostic scan will also give you more specific trouble codes to tell you precisely what is at fault. Your owner’s manual can become handy at this point. However, security issues are impossible to resolve unless you have the appropriate equipment in your garage. If you have none, consult your nearest dealer.

12. Wheel Lock

Another security feature that may potentially be why your car won’t start after running out of gas and refilling is a wheel lock. It is an anti-theft feature where the steering wheel is pushed back against the locking pawl when the key is removed. When in the lock position, you would not be able to turn the key and start your car. Luckily, disengaging this feature is easy – all you have to do is nudge the wheel from side to side as you turn the key. This step will remove the steering wheel from the lock position, allowing you to start your wheeler.

Other Things Worth Checking

Person Checking Engine

While the below parts are not part of the above list, it is important to check them if your car won’t start after getting gas:

Air Filter

An air filter with accumulated debris buildup reduces the airflow into your vehicle’s intake, which ultimately prevents spark and combustion from taking place. Make sure to regularly check your air filter condition and replace it as needed.

Cold Injector

This component is like a regular injector with its own thermo switch and control module that only operates when the engine is cold. If either the switch or the module circuit fails, your engine may not start in cold weather. Fixing issues with this injector requires your service manual.

Fuel Lines

The downside of using ethanol-free fuel is that your fuel lines can freeze in extremely cold weather. Thankfully, adding a can of Iso-Heet to your fuel tank and keeping the tank at least half-full during winter help address this problem. Ensuring your fuel is water-contamination-free also prevents water icicles from forming inside the tank.

Fuse

When a fuse is blown or shorted, it prevents circuitry like fuel injection or the ECM itself from working properly. In turn, these systems prevent your car from starting. Inspecting the wiring of your fuses when the car is shut off will immediately tell you which ones are damaged and require replacement.

Ignition Cylinder

Sometimes, the ignition cylinder (view on Amazon) binds and prevents the engine from turning over. To confirm if this is the problem, remove the cylinder and test to see if it can turn on its own. If it doesn’t, swap it out. Otherwise, you may need to replace both the steering column and ignition cylinder. Do not forget to program the new cylinder and keys to your vehicle’s security system (if you have one).

Ignition Key or Switch

It’s easy to forget that the ignition key/switch – tumblers in lock cylinders, electrical contacts, key bumps, and all – can wear out and become unusable over time. This is especially true for car models where the key is used in the doors and trunk.

PRNDL Shifter

This switch is found only in automatic cars and can malfunction with too many beverage spills or can get worked out of adjustment. When this happens, the computer will recognize the car as being in a parked or neutral state and will not start.

Conclusion – Why Your Car Won’t Start After Getting Gas

To recap, here are 12 of the most common reasons a car won’t start after filling with gas:

  1. Dead or corroded battery
  2. Broken alternator
  3. Bad starter motor or circuit
  4. Lack of spark
  5. Non-working key fob
  6. Unaddressed trouble codes
  7. Restricted fuel filters/injectors
  8. Damaged fuel pump
  9. Jumped or skipped timing belt
  10. Stuck purge control valve
  11. Faulty security system
  12. Wheel lock

Whichever type of troubleshooting you do, refrain from repeatedly cranking your engine in the hopes that it will fire up. Instead, use the charge left in your battery to locate the fault by performing a diagnostic scan, for instance. If cranking multiple times cannot be helped, wait several minutes in between repetitions so as not to drain your battery dry or toast the starter motor. Most importantly, remember to call for help.

Kris Peter

Adventure seeker and off-road enthusiast. I love the thrill of going off-road and taking on the elements.

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