Skip the auto shop - Our mechanics make house calls

Q: Engine swapping on a Subaru

asked by on

I'm interested in engine swap on my Subaru. If it's cold outside, it starts up fine, but if it's hot or the car has been running for a while, it takes multiple times before it turns over. Car runs fine if it starts. The compression is good.

A: When the car starts cold, it needs extra fu...

When the car starts cold, it needs extra fuel. That's just how the cars work. So if you have a normal car that is running perfectly and when you turn the key, the computer sends extra pulse to the fuel injectors so it starts when it is cold.

If your car starts fine when it is cold, but then when it's hot, it doesn't start and you've got to crank it over. That generally means that the fuel injectors are probably leaking or the fuel pressure regulator's leaking. Because a hot engine is hard to start if it has too much fuel. It doesn't need extra fuel. So you probably have a leak in the fuel injection system somewhere. Have the car looked at by a professional so they can locate the leak and make the repairs needed to resolve this issue.

Was this answer helpful?

Need advice from certified mechanic? Get help now!

Over 1000 mechanics are ready to answer your question.
The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details

Ask a Mechanic
(100% Free)

Have a car question? Get free advice from our top-rated mechanics.

Ask A Mechanic
Over 10,000 questions answered!

Get an instant quote for your car

Our certified mechanics come to you ・Backed by 12-month, 12,000-mile guarantee・Save up to 30%

Get a quote

What others are asking

Q: Clutch has noise when pressing clutch pedal - 2015 Subaru WRX

Hey there, a noise when pressing the clutch is generally tied to the throw out bearing or release bearing. It may be necessary to replace the throwout bearing and have the clutch assembly inspected while the transmission is out of...

Q: Car won't start in the morning, but it starts perfectly throughout the day. 2005 Ford Focus

It sounds like your engine does not have fuel pressure held up to the injectors overnight. The fuel pressure is leaking down due to a bad fuel pump check valve, or the fuel pressure regulator is leaking down the pressure....

Q: Ac system

The low vacuum is an indication that there is a leak somewhere in the A/C system, gauges or vacuum pump. I suggest getting this looked at by a certified technician, like one from YourMechanic, who will be able to perform...

Related articles

How Do Power Car Windows Increase Passenger Safety?
Power windows are responsible for approximately 2,000 emergency room visits every year. When a power window closes, it exerts enough force to bruise or break bones, crush fingers, or restrict an airway. Though...
How Long Does a Heater Control Valve Last?
Keeping the right amount of coolant in a car is essential in keeping the engine at the right temperature. Failing to have the right amount of coolant or even bad elements...
P2103 OBD-II Trouble Code: Throttle Actuator Control Motor Circuit High
P2103 means there is a fault with the throttle actuator control motor circuit, likely due to a defective electrical component or part.