Testing a cranks but does not start condition on your Ford 4.6L, 5.4L car, pick up, van or SUV can leave you scratching your head and wondering where to start and/or what to test.
Well, I can tell you that testing a no-start doesn't have to turn into a nightmare and that you can save money by testing certain components before replacing them.
So, in this article I'll present you with some basic working theory that you need to know to get to the bottom of why your vehicle does not start and where to find some of the testing articles.
Contents of this tutorial:
You can find this tutorial in Spanish here: Cómo Probar Un Arranca Pero No Prende (4.6L, 5.4L Ford V8) (at: autotecnico-online.com).
Important Tips And Suggestions
A a cranks but does not start condition means that your vehicle's starter motor is cranking the engine but the engine is not starting.
A no-start condition is usually due to a problem provoking a lack of fuel or spark to the engine and this tutorial concentrates on troubleshooting this type of problem.
A no-crank condition means that the engine is not cranking when you turn the key to crank the engine.
If your Ford vehicle is experiencing a no-crank condition, you probably should start by checking the starter motor. The following tutorials may be of help:
- How To Test The Starter Motor (Ford 4.6L, 5.4L).
- How To Test A Does Not Crank Condition (Case Study) (at: easyautodiagnostics.com).
Alright, let's get started with the next subheading.
No Start Condition Basics
The most important thing that you need to keep in mind, when you're faced with your Ford vehicle cranking but not starting is that the engine needs air, fuel and spark to start.
If any one of these is missing from the mix, your 4.6L, 5.4L Ford pick up (car, van, or SUV) will not start. It really is as simple as that (theoretically speaking that is and who speaks theoretical now-a-days?). OK, so when it's time to test specific components, we need to look at these three area:
- The ignition system is the one responsible for creating and delivering spark. Without spark, the engine will crank but not start.
- Depending on whether your specific Ford has a coil pack or Coil-On-Plug ignition system, the ignition system will include the following components:
- Crank sensor
- Ignition module
- Coil packs
- Spark plug wires
- The thing to keep in mind about the ignition system is that all engine cylinders must get spark and the one thing that will stop the ignition system from creating spark on a wholesale scale is a bad crank sensor.
- The fuel system is the one responsible with supplying the engine with fuel.
- The fuel system components that play a major part in starting your Ford vehicle are:
- Fuel pump.
- Fuel pump inertia switch.
- Fuel pump relay.
- Fuel injectors.
- All of these components can be tested to make sure they're bad before replacing them.
Engine Mechanical System
- The engine pistons and valves (and all the other related components like: timing chains, etc.) are the ones responsible for the induction of the fresh air the engine needs for the combustion process.
- Although rare, internal engine mechanical problems can and do cause no-start conditions.
- Possible internal engine problems are:
- Blown head gasket.
- Blown engine.
- Broken timing chain.
OK, the list of possible things that can go wrong looks pretty long but rarely do you see various failures in separate systems at the same time.
The cool thing is, is that there is a diagnostic strategy that you can use to figure out exactly what's wrong with your particular no-start problem. Let's find out more about it in the next subheading.