STEP 2: Testing The Fuel Pump's Pressure
Your next step is to check the fuel pump (after confirming that the ignition system is not behind your engine's no-start problem).
The fuel pump test involves checking its fuel pressure output with a fuel pressure test gauge.
Why should you check the fuel pump pressure with a fuel pressure test gauge? Because it's one of the most accurate ways of testing the fuel pump.
This fuel pressure test gauge is connected to the fuel system with an adapter. This adapter is connected between the fuel injector rail and the fuel pressure line.
You can find the fuel pressure specifications here:
You can find the fuel pump pressure test explained in a step-by-step manner here:
The fuel system is NOT causing the no-start problem if:
- Fuel pressure is within specification.
If the fuel pressure gauge registers the indicated fuel pressure specification, then you can confidently conclude that the fuel pump is working and delivering enough fuel to the fuel injectors.
You can also conclude that the fuel pump is not behind the engine's no-start problem.
The next step is to check for a blown head gasket. Go to: STEP 3: Checking For A Blown Head Gasket.
The fuel system IS THE CAUSE of the no-start problem if:
- Fuel pressure is 0 PSI (or anything below the fuel pressure specification).
This confirms that the no-start problem is caused by a lack of fuel. This usually means that the fuel pump is bad and needs to be replaced.
STEP 3: Checking For A Blown Head Gasket
A head gasket failure is usually the result of an engine overheating issue.
The 4.0L V6 engine in your Ford Ranger or Mazda B4000 comes equipped with two cylinder head gaskets.
There are 4 specific tests to check for a blown head gasket, and you can find them explained in this tutorial:
A blown head gasket is NOT causing the no-start problem if:
- The engine oil has a normal color (in other words, it doesn't have a milky-white color).
- The coolant in the radiator remains undisturbed when cranking the engine (with the radiator open).
- The engine passed a block test.
Your next test is to check the engine's compression. Go to: STEP 4: Making Sure The Engine Has Good Compression.
A blown head gasket IS THE CAUSE of the no-start problem if:
- The engine oil has a milky-white color (like coffee with too much creamer).
- - or -
- The coolant in the radiator shot out when cranking the engine (with the radiator open).
- - or -
- The engine failed a block test.
STEP 4: Making Sure The Engine Has Good Compression
The engine compression test will tell you if the cylinders are producing enough compression to ignite the air/fuel mixture within them.
The engine compression test is usually performed after eliminating the ignition system and the fuel pump as the cause of the engine no-start problem.
The following engine compression test tutorial explains how to do the test and, more importantly, how to interpret its results:
An engine compression problem is NOT causing the no-start problem if:
- The compression of each cylinder is above 120 PSI.
An engine compression problem IS THE CAUSE of the no-start problem if:
- 2 or more cylinders have 0 PSI compression.
- - or -
- All cylinders have 0 PSI compression.
No-Start Troubleshooting Summary
Quite a few things can cause the engine not to start. But as this tutorial has brought out, there's a process you can follow to find out what's causing it.
The most important thing to remember when diagnosing an engine no-start problem is that the engine needs 3 things to start.
These 3 things are:
- Spark.
- Fuel.
- Air (compression).
When the engine does not start, one of these is missing from the mix.
Therefore, testing an engine no-start problem literally boils down to a process of elimination.
Once you've confirmed that you've got spark at all cylinders, there isn't any need to spend time testing the ignition system. The next step is to make sure the fuel pump is working and so on.
By checking these basic things (spark, fuel, air), you'll save yourself the frustration of replacing components that won't solve the problem.
More 4.0L Ford Ranger (Mazda B4000) Tutorials
You can find a complete list of 4.0L Ford Ranger (Mazda B4000) tutorials in this index:
Here's a small sample of the tutorials you'll find in the index:
- Fuel Pressure Specifications (1991-2011 4.0L Ford Ranger And Mazda B4000).
- How To Test Engine Compression (1991-2011 4.0L Ford Ranger And Mazda B4000).
- How To Test For A Blown Head Gasket (1991-2011 4.0L Ford Ranger And Mazda B4000).
If this info saved the day, buy me a beer!
