Testing the fuel pump has become a whole lot easier, now that you can find a fuel pressure gauge test kit with the necessary adapter to tap into the fuel pressure line on your 1.6L Honda Civic.
In this tutorial I'm gonna' I'll explain the fuel pressure test and also how to check for a lack of fuel with starting fluid.
Contents of this tutorial:
You can find this tutorial in Spanish here: Cómo Probar La Bomba De Combustible (1995-2000 1.6L Honda Civic) (at: autotecnico-online.com).
RELATED WIRING DIAGRAMS:
- Fuel Pump Circuit Wiring Diagram (1996-1998 1.6L Honda Civic).
- PGM-FI Main Relay Circuit Diagram (1996-1998 1.6L Honda Civic).
The fuel pump gets power from the PGM-FI Main Relay. If you find that you need to test the PGM-FI Main Relay, you can find the test tutorial here:
Symptoms Of A Bad Fuel Pump
A bad fuel pump doesn't necessarily mean that it has stopped working (and keeping your Civic from starting). Sometimes a fuel pump fails slowly, where it works but doesn't send enough fuel volume to the fuel injectors.
Obviously, when the fuel pump completely fails your 1.6L Honda Civic isn't gonna' start. In this type of scenario, you'll see that:
- The engine turns over but will not start.
- The distributor is feeding spark to all 4 cylinders.
- The PCM will still pulse (activate) all of the fuel injectors.
But when the fuel pump sends a lower than normal volume of fuel, the air/fuel mixture will run very lean and cause quite a few performance issues. You'll probably see one or more of the following symptoms:
- Rough idle.
- Engine starts after extended cranking.
- Lack of power when accelerating the vehicle down the road.
- Back-fires thru' the intake manifold when accelerating your car down the road.
Both of these conditions can be tested with a fuel pressure gauge. Alright, with this info under our belts, let's get testing.
Where To Buy A Fuel Pressure Test Gauge
You can buy a fuel pressure test gauge just about anywhere and is one of the most important tools any serious DIY'er should have in his/her tool box.
The following fuel pressure test gauge kits are pretty good deals and include the banjo-bolt test adapter:
NOTE: Before choosing a fuel pressure test gauge, you need to know what type of banjo bolt sits on top of the fuel filter. For more info see the next section: Type Of Banjo Bolt On Fuel Filter.
TEST 1: Checking Fuel Pressure With A Fuel Pressure Gauge
A fuel pressure test gauge, with the necessary adapter to tap into your Civic's fuel system, is not expensive. This is good news because using a fuel pressure test gauge is the best way to test the condition of the fuel pump (don't have one, take a look at: Where To Buy A Fuel Pressure Test Gauge).
So, in this test section, we'll use a fuel pressure test gauge to check the fuel pump's output pressure. The fuel pressure specification for your Honda Civic, if it starts and runs, is: 30 to 37 PSI (with the fuel pressure regulator's vacuum hose connected) and 38-47 PSI (with the fuel pressure regulator's vacuum hose disconnected.).
If your Civic's engine doesn't start, you should look for the fuel pressure to be somewhere between 38-47 PSI (whether the vacuum hose is connected or disconnected from the fuel pressure regulator).
Lastly, the fuel pressure gauge is connected to the fuel system by using an adapter that connects to the fuel filter's banjo bolt (also known as just the union bolt) (see photo above).
OK, let's get started with this test:
Disconnect the distributor from its electrical connector.
This is just a safety precaution and will prevent the engine from starting.
Place a shop towel around the fuel filter's banjo bolt. The shop towel's job is to absorb any fuel that may leak when doing step 3.
Remove the 6mm bolt located on top of the fuel filter's banjo bolt. Now, connect the fuel pressure test gauge to adapter to the fuel filter's banjo bolt.
NOTE: Use the appropriate adapter that applies to the particular banjo bolt type of your 1.6L Honda Civic (since some 1.6L Civic's don't use the 6mm bolt on top of the fuel filter's banjo bolt). For more info about this see: Type Of Banjo Bolt On Fuel Filter
When ready, ask your helper to cycle the key on and off but don't crank the engine while you observe the fuel pressure tester's gauge.
Check the connection at the fuel filter for fuel leaks and if any, eliminate them.
Have your helper crank the engine. The engine will not start since the distributor is disconnected from its electrical connectors.
Your fuel pressure gauge should register: 38 to 47 PSI with the Key On Engine Off (KOEO) if the fuel pump is OK.
Let's take a look at what your results mean:
CASE 1: If the fuel pressure gauge registered 0 PSI. This confirms that the cause of your 1.6L Honda Civic engine's no-start problem is caused by a lack of fuel.
Now, I usually take one more precaution, before condemning the fuel pump as bad and this is to check that the fuel pump is getting 12 Volts as the engine is cranking. This is just to make sure that the fuel pump relay and fuse are OK and doing their job.
What you'll have to do to accomplish this is to attach a multimeter in Volts DC mode to the wire that supplies this voltage to the fuel pump and while a helper cranks the engine, you'll verify that the fuel pump is getting this power. If the 12 Volts are being supplied to the fuel pump, you have now 100% verified that the fuel pump is fried and needs to be replaced.
CASE 2: If the fuel pressure gauge registered 38 to 47 PSI: This fuel pressure gauge result lets you know that the fuel pump is working and delivering enough fuel to the fuel injectors. The reason your 1.6L Honda Civic is not starting is due to another reason. The fuel pump is OK.