How To Troubleshoot A No Start (Ford 4.0L)

Testing a Cranks but Does Not Start condition on your 4.0L Ford Explorer (Aerostar, Ranger, Mountaineer) doesn't have to be hard. In this tutorial, I'll go into the basics of a No Start Condition and show you some of the step-by-step tutorials that'll help you get to the bottom of the problem.

Here are the contents of this article at a quick glance:

  1. Difference Between a No Crank and a No Start Condition.
  2. No Start Condition Basics.
  3. No Start 1: Checking For Spark.
  4. No Start 2: Checking For Fuel.
  5. No Start 3: Checking Engine Mechanical Condition.
  6. No Start Summary.
  7. Related Test Articles.

En Español You can find this tutorial in Spanish here: Cómo Probar un Arranca Pero No Prende (4.0L Ford) (at: autotecnico-online.com).

Difference Between a No Crank and a No Start Condition

There's a big difference between a No Crank and a No Start Condition. Here's a brief description of both conditions:

No Start Condition: The engine cranks (turns over) like it wants to start... but it never does. The usual culprits are:

  1. Failed crank position sensor.
  2. Failed fuel pump.

No Crank Condition The engine does not turn over when you turn the key to start your Ford vehicle. This is usually due to:

  1. Failed starter motor.
  2. Failed neutral safety switch.
  3. Failed ignition switch.
  4. Locked up engine.

This tutorial is geared toward a Cranks but Does Not Start Condition.

No Start Condition Basics

To successfully troubleshoot the cause of the No Start Condition of your Ford 4.0L equipped car or mini-van, you need to know that there are three very basic components the engine needs to start and they are:

  1. Air.
  2. Fuel.
  3. Spark.

So, when your Ford 4.0L Explorer (Aerostar, Ranger or Mountaineer) Cranks but Does Not Start...it's because one of these components is missing from the mix.

This basic piece of information will make you aware that you need to see if the problem is being caused by a problem in the fuel system, or in the ignition system, or in the Engine Mechanical system.

Here are some more specifics:

1.)  Ignition System

  1. The ignition system is the one responsible for creating and delivering spark. Without spark, the engine will Crank but Not Start.
  2. The ignition system of the Ford 4.0L equipped vehicles covered by this article use a distributor-less ignition system. More specifically, it uses a coil pack type ignition system.
  3. In my experience, the most common component failures, of the ignition system that cause a No Start No spark Condition are:
    1. No power to the ignition coil pack.
    2. BAD crankshaft position sensor.
  4. The ignition system components can be tested in a methodical way to find out exactly what has failed (if indeed something has).

2.)  Fuel System

  1. The fuel system is the one responsible with supplying the engine with fuel.
  2. The fuel system component that causes the majority of No Start No Fuel problems:
    1. Fuel pump relay.
    2. Fuel pump.
    3. Fuel pump inertia switch (that has activated and has shut down the fuel pump).
  3. The fuel pump (along with the other 2 components) can be tested to make sure it has really fried.

3.)  Engine Mechanical System

  1. The engine pistons and cylinder head 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.
  2. Although rare, internal engine mechanical problems can and do cause No Start Conditions.
  3. Possible internal engine problems are:
    1. Blown head gasket.
    2. Blown engine.
    3. Broken timing chain (although this very rare).

OK, the list of possible things that can go wrong looks pretty long... but it is rare to see (or have) two different components go BAD from two 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...