No Start 2: Checking For Fuel
If the fuel does not reach the fuel injectors or if the injectors do not spray the fuel into the engine cylinders, for whatever reason, you'll get a no-fuel no-start condition.
The usual suspect behind this is the fuel pump. The fuel pump test should be conducted with a fuel pressure gauge, so that you can get an accurate result you can trust (any other method may have you wasting time and money on a fuel pump your vehicle does not need).
CASE 1: Fuel pressure is at specification. Not only does this result tell you that the fuel pump is OK but that the following components, that supply the fuel pump with power, are OK too:
- Fuel pump fuse.
- Fuel pump relay.
- Fuel pump inertia switch.
The cool thing about using a fuel pressure gauge to test the fuel pump, is that once you've confirmed that the fuel pressure is at specification, there's no need to spend time testing them or money replacing them.
CASE 2: Fuel pressure IS NOT present. This usually means that the pump has failed, but not always.
Before condemning the fuel pump as bad, you need to make sure that the fuel pump inertia switch has not tripped and therefore blocking power from reaching the fuel pump.
If the inertia switch has not been tripped, then I would recommend testing/checking that the fuel pump is receiving power anyway (to indirectly test the fuel pump relay):
- After verifying that no fuel pressure exists, check that the fuel pump is getting power (12 Volts).
- This can be done by tapping into the power circuit that feeds the pump with 12 Volts with a multimeter (but without dropping the fuel tank to remove the fuel pump).
- Once you're tapped in, have a helper crank the engine while you observe your multimeter in Volts DC mode. If voltage is present (12 Volts), then you have confirmed that the fuel pump fuse, fuel pump relay and inertia switch are working perfectly.
- If your multimeter registers 12 Volts, you cam replace the fuel pump with confidence, since this confirms the fuel pump as bad.
- If no voltage is present, as your helper cranks the engine, then the fuel pump should not be replaced. You need to find the cause of these missing voltage.
No Start 3: Checking Engine Mechanical Condition
One of the most overlooked areas, when testing a hard to diagnose no-start, is the mechanical condition of your Ford 3.0L or 3.8L equipped car, mini-van or pick up.
Checking the engine mechanical condition means an engine compression test.
- When performing an engine compression test, what you're looking for is an average compression reading of less than 90 PSI across all or the majority of the engine cylinders.
- If you have one or just two readings that are under 90 PSI your Ford vehicle will still start and run, albeit with a misfire condition.
- I've written a how to do a compression test article that you may find useful. Although this article is geared towards finding a hard to diagnose misfire, if you have never done a compression test, this article will help you: How To Do And Interpret An Engine Compression Test (Ford 3.0L, 3.8L).
No Start Summary
So many different things can cause a no-start condition that troubleshooting it can turn your Ford vehicle into a money pit, if you don't have a basic diagnostic strategy. The key to saving yourself time and money is checking for the basics first. The basics are spark and fuel.
To check the basics, you need tools. There's just no way around it. One of the analogies that I've always enjoyed repeating, about doing a job without the right tools is like trying to eat a bowl of soup with a fork.
So besides knowing what to test, you need tools to do those tests. You don't have to spend an arm and a leg, since you can buy a lot of diagnostics tools that are tailored for the pocket-books of the serious do-it-yourself-er. Here are some of the basic tools you'll need:
- Fuel pressure gauge.
- Spark tester.
- Compression gauge.
- Multimeter.
Related Test Articles
You can find a complete list of tutorials here: Ford 3.0L, 3.8L Index Of Articles. Below, is a sample of articles you'll find in this index of articles:
- How To Do And Interpret An Engine Compression Test (Ford 3.0L, 3.8L).
- Ignition Coil Test (Ford 2.9L, 3.0L, 3.8L).
- How To Test For A Blown Head Gasket (Ford 3.0L, 3.8L).
- Coil Pack Test (at easyautodiagnostics.com).
If this info saved the day, buy me a beer!
