It's super easy to test the fuel pump's pressure with a fuel pressure test gauge on the 1987-1996 Ford E-Series full-size vans.
In this tutorial, I'm going to explain how to test the fuel pump using a fuel pressure test gauge.
I'm also including instructions on how to perform a starting fluid test, which will help you find out if the fuel pump is causing a no-start problem.
Contents of this tutorial:
APPLIES TO: This tutorial applies to the following vehicles:
- Ford E150: 1987, 1988, 1989, 1990, 1991, 1992, 1993, 1994, 1995, 1996.
- Ford E250: 1987, 1988, 1989, 1990, 1991, 1992, 1993, 1994, 1995, 1996.
- Ford E350: 1987, 1988, 1989, 1990, 1991, 1992, 1993, 1994, 1995, 1996.
WIRING DIAGRAMS: The following fuel pump circuit wiring diagrams may come in handy:
- Fuel Pump Wiring Diagram (1992-1993 Ford E150, E250, E350).
- Fuel Pump Wiring Diagram (1994-1995 Ford E150, E250, E350).
- Fuel Pump Wiring Diagram (1996 Ford E150, E250, E350).
Symptoms Of A Bad Fuel Pump
For the most part, a bad fuel pump will cause one of two problems:
- The engine is not going to start.
- The engine is going to start, but it's not going to run correctly.
If the fuel pump still functions but doesn't send the correct amount of fuel, you'll see one or more of the following symptoms:
- The engine takes longer than usual to start (extended cranking).
- The engine's idle is very rough.
- The engine backfires thru' the intake manifold under load.
- The engine starts then dies.
The fuel pump pressure test will let us know if the fuel pump is behind any of these symptoms (or not).
Where To Buy A Fuel Pressure Test Gauge
The fuel pressure test gauge is one of those must-have tools to diagnose the fuel injection system on the fuel-injected Ford E150 (E250, E350).
The following fuel pressure test kits have the adapter you'll need to connect the gauge to the Schrader valve on the fuel injector rail.
Using A Fuel Pump Pressure Tester To Test The Fuel Pump
As I mentioned at the beginning of the tutorial, it's super easy to test the fuel pump's pressure with a fuel pressure test gauge.
This is because your Ford E150 (E250, E350) van's fuel system comes equipped with a Schrader valve, and it's to this valve that we can connect a fuel pressure test gauge.
The location of the Schrader valve is on the fuel injector rail. Photo 1 of 2 shows the Schrader valve on the 5.0L and 5.8L V8 engines.
Photo 2 of 2 shows the location of the Schrader valve on the 4.9L L6 engine.
NOTE: If you don't have a fuel pressure tester with the correct adapter, take a look at this section: Where To Buy A Fuel Pressure Test Gauge.
The fuel pump pressure for the 1987-1996 4.9L E-Series vans is:
- 50-60 PSI Key On Engine Off (KOEO).
- 45-60 PSI Key On Engine Running (KOER).
The fuel pump pressure for the 1987-1996 5.0L, 5.8L V8 E-Series vans is:
- 35-45 PSI Key On Engine Off (KOEO).
- 30-40 PSI Key On Engine Running (KOER).
OK, these are the test steps:
Place a shop towel around the Schrader valve. The shop towel will absorb any fuel that may leak when doing step 3.
Remove the plastic protective cap from the Schrader valve.
Connect the test adapter to the Schrader valve.
Connect the fuel pressure gauge to the adapter.
When ready, ask your helper to cycle the key on and off but don't crank the engine while observing the fuel pressure tester's gauge.
Check your connections for fuel leaks.
Crank the engine and check the fuel pressure gauge. Your fuel pressure gauge should register the specified fuel pressure.
Let's examine your test result:
CASE 1: The fuel pressure test gauge registered 0 PSI. This test result confirms that the engine is not starting due to a lack of fuel.
You can conclude that the fuel pump is not functioning and is the cause of the engine's no-start problem.
CASE 2: The fuel pressure gauge registered the indicated fuel pressure specification. This is the correct and expected test result and it confirms that the fuel pump is OK.
CASE 3: The fuel pressure gauge registered a fuel pressure way below the specification. This test result lets you know that the fuel pump is failing. Replace the fuel pump.