I have a hot-start problem in my 2003 Ford Ranger. The Ranger will start cold, but after being driven for a while and shut down, the engine will not restart. The starter is OK.
This is certainly a frustrating problem, but it shouldn’t be too tough to fix if you’re willing to become part of the diagnostic team. By your description, it sounds like during a hot-soak restart the Ranger starter cranks fine, but the engine fails to start. “Hot soak” refers to the elevated under-hood temperature that can occur during the first fifteen minutes or so after engine shut-off. Our three categories of concern will be:
Fuel pressure, particularly the fuel pump and related parts.
Fuel injector drive, or correct pulsing/clicking.
Spark, or the ignition system delivering high-voltage pulses to the spark plugs.
First, some questions: Does the “check engine” light come on while driving? If so, helpful trouble codes may be stored. Does the no-start condition happen in a regular or predictable manner? That is, can you learn its habit so the fault can be duplicated? If you can duplicate the condition, do so for a professional technician.
If the fault is difficult to duplicate, let’s spend a little time learning two normal sounds when the truck isn’t acting up, so you can report your findings to the tech. Fuel pump: With the gas cap removed, listen carefully near the filler neck while a helper turns the key to the run position (run only, not cranking). You should hear a hum for about two seconds, then it will stop. Learn this sound.
Another important sound is fuel-injector clicking. This one is a little more tricky — find a friend with under-hood savvy to point out the easiest-to-reach injector, and the safest way to observe it clicking. A long hardwood stick or screwdriver held to the injector while the engine is cranked or running should yield a noticeable clicking or vibration. If you do not have a clear understanding of moving parts and other under-hood hazards, do not attempt this!