TEST 2: Using Starting Fluid
The starting fluid test comes in handy when you don't have a fuel pressure test gauge.
Although the starting fluid test isn't the most accurate way of testing a fuel pump, it can help point your engine no-start diagnostic in the right direction.
It's important to know that the starting fluid test depends on all spark plug wires sparking.
So if you haven't already, check that all six spark plug wires are sparking before you start the starting fluid test.
These are the test steps:
- 1
Remove the intake air duct from the throttle body. You don't have to completely remove it, since you'll have to reconnect it in one of the next steps.
- 2
Open the throttle, manually, and spray starting fluid down the bore.
- 3
When you have sprayed a good squirt of starting fluid, quickly reconnect the air duct to the throttle body (you don't have to tighten the hose clamp).
IMPORTANT: Reconnecting the intake air duct is a very important safety precaution in case you get a back-fire thru' the intake manifold. - 4
Have your assistant crank the engine once the intake air duct is back on the throttle body.
- 5
You'll get one of two results with this test:
1.) The engine will start momentarily and after a few seconds will die.
2.) The engine will only crank but not start at all.
OK, let's find out what your results mean:
CASE 1: The engine started and ran for a few seconds. This test result lets you know that the engine no-start problem is due to a lack of fuel.
Generally, you can conclude that the fuel pump has failed. But if I were in your shoes, I would check the fuel pressure with a fuel pressure test gauge to make sure.
CASE 2: The engine did not start, not even momentarily. This test result lets you know that your Ford Ranger or Mazda B4000's engine no-start problem is not due to a lack of fuel.
This test result is accurate only if all 6 spark plug wires are sparking.
Checking The Fuel Pump Inertia Switch
Your 4.0L Ford Ranger (Mazda B4000) comes equipped with a fuel pump inertia switch, whose job is to cut power (or Ground) to the fuel pump in case of an impact.
When an impact trips the fuel pump inertial switch, the engine will stall (if it is running) or crank but not start due to a lack of fuel.
Although the fuel pump inertia switch trips during a severe impact (such as one caused by an automobile accident) by design, frequently a less than severe impact trips it.
You should always check and reset the inertia switch and try starting the engine before testing the fuel pump.
The location of the inertia switch is below the right side of the instrument panel, behind the trim panel, on most of the vehicles covered by this tutorial.
Resetting the fuel pump inertia switch involves pushing down the button located on top of it until the button bottoms out. You'll feel a definite 'click' as you depress the button if the inertia switch is tripped and is cutting power to the fuel pump.
Where To Buy The Fuel Pump And Save
The following links will help you comparison shop for the fuel pump:
Not sure if the above fuel pumps fit your particular 4.0L Ford? Don't worry, once you get to the web-site they'll make sure it fits (by asking you for the specifics of your vehicle). If it doesn't fit, they'll find you the right one.
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!
