Troubleshooting a Car That Doesn’t Start When the Engine is Hot
If your car starts fine when the engine is cold but won’t start when the engine is hot, it can be a frustrating problem to diagnose. There are a number of potential causes, but the most common ones include:
1. Faulty Fuel Pump
The fuel pump is responsible for delivering fuel from the gas tank to the engine. When the engine is hot, the fuel can vaporize and create bubbles in the fuel line. These bubbles can prevent the fuel pump from delivering enough fuel to the engine, which can cause the engine to stall or not start at all.
To test the fuel pump, you can use a fuel pressure gauge to measure the pressure in the fuel line. If the pressure is too low, it could be a sign that the fuel pump is failing.
2. Faulty Ignition Coil
The ignition coil is responsible for providing the spark plugs with the high voltage they need to ignite the air-fuel mixture in the cylinders. When the engine is hot, the ignition coil can overheat and fail to produce a strong enough spark. This can cause the engine to misfire or not start at all.
To test the ignition coil, you can use a multimeter to measure the resistance between the coil’s terminals. If the resistance is too high or too low, it could be a sign that the ignition coil is failing.
3. Faulty Crankshaft Position Sensor
The crankshaft position sensor is responsible for detecting the position of the crankshaft and sending this information to the engine’s computer. The computer uses this information to control the timing of the spark plugs and fuel injectors. When the engine is hot, the crankshaft position sensor can overheat and fail to send the correct information to the computer. This can cause the engine to run erratically or not start at all.
To test the crankshaft position sensor, you can use a scan tool to read the sensor’s output. If the output is erratic or incorrect, it could be a sign that the sensor is failing.
4. Other Potential Causes
In addition to the three most common causes listed above, there are a number of other potential causes for a car that doesn’t start when the engine is hot. These include:
- Faulty starter
- Weak battery
- Clogged fuel filter
- Overheated engine
- Electrical problems
If you are experiencing this problem, it is important to have your car diagnosed by a qualified mechanic. They will be able to determine the cause of the problem and recommend the best course of action.
