Car Won’t Start Until It Cools Down [4 Easy Solutions]

Your car won’t start until it cools down due to a failed crankshaft position sensor, a bad fuel pressure regulator, and a faulty fuel pump. 

If you don’t deal with those issues and solve them, you can’t run your engine smoothly. And this guide will walk you through the steps to troubleshoot those problems and fix them. So, keep reading till the end. 

car won't start until it cools down

Car Won’t Start Until It Cools Down [4 Easy Solutions]

Don’t know why your car won’t start when it’s hot? Then, this chapter will disclose all the caveats that cause your car to not start until the engine cools down. 

1. Crankshaft Position Sensor Goes Bad

A defective crankshaft position sensor can be the caveat that prevents your car from starting until you leave it for a few minutes to cool. When your engine remains warm, the internal winding in the sensor expands. Consequently, it fails and stops the car from starting until it cools down. 

Stalling or hard starting, engine misfires, and engine refusing to crank or start are some signs of a bad crankshaft position sensor. And a failed crankshaft sensor means you won’t get any spark to start the engine. 


Once you determine the crankshaft sensor is at fault, you must replace it to solve the no-start issue. It’s pretty simple to change a bad crankshaft position sensor. You can read our guide on what to do after replacing the crankshaft sensor.

2. Bad Fuel Pressure Regulator

A fuel pressure regulator regulates the continuous fuel delivery by opening and closing the bypass valve. If it fails, it can’t adjust the right fuel-air ratio. As a result, the engine won’t get the amount of fuel it needs to start the engine. 

Engine backfires, reduced fuel economy, poor acceleration, and the engine won’t start are some common signs of a failed fuel pressure regulator. 


Before replacing the fuel pressure regulator, you should diagnose it. And this video will help in diagnosing the FPR: 

If the inspection says the fuel pressure regulator goes bad, you must replace it. Regarding this, you can read our guide that will help you with bad GM TBI fuel pressure regulator symptoms and a replacement guide.

3. Leaky Fuel Injectors

A broken or leaky fuel injector can also cause your car to not start. If the fuel injectors fail, they can’t deliver the proper air-fuel ratio to the engine. As a result, your vehicle will suffer from poor acceleration. In the worst case, you can’t even start the engine.

The poor oil quality, heat soak, and engine blow-by are some reasons that cause the fuel injectors to go bad. When the fuel injectors get damaged, you will go through these problems: poor fuel economy, rough idling, loss of engine power, and struggling to start the engine. 


You should replace the leaky fuel injectors to ensure your engine gets a proper fuel-air ratio for running the engine smoothly. Before making the replacement, ensure the engine compartment is cold. Then, you can read this article on how to replace fuel injectors.

4. Faulty Fuel Pump

A faulty fuel pump also causes your car to not start. There are a lot of things to blame if the fuel pump is not working. Electrical faults, fuel contaminants, and old age are some proven caveats that cause your fuel pump to go bad.


Replacing the bad fuel pump is a must to solve the no-starting issue. If you are mechanically inclined, this video will save you up to $220 to $1000: 

Alternatively, you can hire a professional to replace the fuel pump for you. But you need to spend that amount of money on this. 


Why won’t my car start when the engine is hot?

Your car won’t start when the engine is hot due to a faulty crankshaft sensor, a blocked air filter, and a defective battery connection. 

Why does my car only start when it’s cold?

The cold starting issue is the result of a defective fuel pump and a failing temperature sensor.

What causes hot start issues?

A bad connection to the battery terminal, a faulty starter solenoid, and a bad starter is some culprits behind the hot start issues. 

What are the symptoms of a faulty starter?

Here are some common signs of a faulty starter: 
1. The engine won’t turn on 
2. Grinding noise
3. Smoke coming out of the engine 

What is the most common engine starting problems?

A dead battery is the most common engine start issue. Turns out, that a defective starter, clogged fuel filter, and a failed ignition chamber are also responsible for the engine starting problem.


It’s a pain in the neck if you have to wait up to 30 minutes for your car to let it cool down. Generally, your car won’t start when it is hot due to a faulty crankshaft sensor, a bad fuel pump, and a bad fuel pressure regulator. Fortunately, we mentioned every troubleshooting step to fix those issues. So, follow our guidelines and fix the no-starting issue. 

About John M

John contributed as a technical head at an automobile company just 2 years after his post-graduation in Automobile Engineering. He loves to lead a free life, so he left his job & started blogging. Now, he does research on every automotive problem, part & product and seeks a better solution & best products & shares his findings with his readers to help them as well as to minimize their struggle.

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