How To Test A Fuel Pump Out Of The Car Before Installing It

Last updated on June 28th, 2022 at 03:53 pm

In this article, we have taken the pleasure to explain how you can test a fuel pump out of the car, before installing it. You would also be learning different ways you can test a fuel pump. read also on fuel cap check engine light

How To Test A Fuel Pump Before Installing It

One of the ways by which you can test a fuel pump before you proceed to install it is by attaching 12 volts to it. On other hand, you could just test it by getting a container of gas, hooking up the hose and dropping the pump into the container. You would then have to hook up a gauge so as to observe the amount of pressure being produced, or you could as well simply aim the hose back into the container, if you only want to see it pump gas. However, we strongly caution you to be very careful as gas is highly volatile and could cause severe damage. We still recommend using the first option of hooking 12 volts and seeing if the car would run.

You can test a fuel pump before installing it by using a multimeter. Here, you have to observe the continuity of the connector and motor windings as you use it. If the pump is working well, then, the resistance of the windings should be reading between 2 ohms and about 10 ohms.

Testing Fuel Pump With Battery

Testing fuel pump with battery is actually possible and a recommendable idea. It is more or less the way of testing your car fuel pump before installing it. However, you can test your car fuel pump with battery even after installing it. All you have to do is check for +12 volts between the top of fuse 32. The aim is to provide 12 volts directly to the pump and totally bypass the normal process of the ECU receiving the signal from the CPS for FP to function. If there is nothing wrong with your CPS, ECU and FP relay, then you should notice the +12V. However, if there is a problem with your FP or you have a bad wiring, the pump would most likely not run. If the test works well, then you would be able to hear the sound of the fuel pump running even from inside your car provided your windows are up. If you lift the rear seat bottoms, you may have a chance of listening to it closely.

How To Test A Fuel Pump Without A Pressure Gauge

There may be absolutely no reason to test a fuel pump without a pressure gauge. To some people, it may sound absurd and most likely impossible. However, we will be explaining to you how you can test your fuel pump even without a pressure gauge. For this test, you may need the ECM used to harness the control of the pump. You will find a two-wire oil pursuit switch at the back of the distributor fitted off the brass fitting that is screwed into the china wall. You would need to connect it along with the oil pressure sending unit for the dash gauge. This would be a one-wire unit.

Thereafter, all you have to do is test the fuel pump by disconnecting the rubber supply line and then jumping the fuel pump relay. This fuel pump relay will resemble the fan relay. However, it is necessary that you are able to distinguish which wire is which by tracing them. Usually, the fan relay wire should be on the left. Conclusively, make sure that the fuel is flowing, while the pump is working. In this way, you would be able to test your fuel pump without a fuel pressure gauge.

How To Check Fuel Pump Pressure Without A Pressure Gauge

Indeed, you can check your fuel pump pressure without a pressure gauge. This can be done, using a tire gauge. However, there is the risk of unexpected ignition as the material in the gauge is very much compatible with gasoline. We do not fully recommend this but if the situation is urgent, then you carefully can try it for both high and low fuel pump pressure. You should also keep in mind that there could be inaccuracies in your test result. After all, tire gauges are designed for the purpose of checking the pressure in tires. It is better to check for fuel pump pressure the right way with a pressure gauge or simply take it to a professional to test it for you.

How To Test High Pressure Fuel Pump

Do you know that high pressure fuel pump can be quite bad? This is why it is important to know the symptoms that would notify you of a potential problem with your high pressure fuel pump. These are the signs that would alert you of a bad high pressure fuel pump:

1. Difficulty in starting the car or ignition.

2. When you notice frequent stalling at high temperatures.

3. Hearing whining noises coming from your fuel tank

4. When your engine begins to sputter as you drive at high speed

5. Vehicle surging

6. When you experience low gas mileage

7. When your car loses power under stress such as moving up a hill or carrying heavy load.

Below are the steps that would guide you in carrying out a high pressure fuel pump test. This method is called the electricity method.

1. Find the fuse that corresponds to the fuel pump and inspect it.
2. Check the voltage from the pump itself
3. Use a voltmeter to carry out a drop test.
You can also use the fuel pressure gauge method. Below are the steps:
1. Get a pressure gauge
2. Hook up the hose to the fuel pump
3. Get someone to help you rev the engine, while you observe the gauge

Conclusion on How To Test A Fuel Pump Out Of The Car Before Installing It

In conclusion, this is all there is to know about testing a fuel pump before installing it (testing a fuel pump with battery, testing a fuel pump without a pressure gauge, and testing a high pressure fuel pump). We hope you have benefited from the knowledge shared with you here in this article. Good luck in testing your fuel pump in any of the ways discussed above.

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What to read: Symptoms of a Bad fuel pump

Jeffery Ekweghi

Hi dear, my name is Jeffery Ekweghi, and I am a certified mechanic and autobody parts technician. I created this site to share my expertise and experience with car lovers looking to resolve their car-related issues. I am certified in private cars and heavy-duty commercial vehicles. I have worked as a mechanic since 2015 and have experience in vehicle brands like Subaru, Jeep, Toyota, TATA, BMW, Mazda, Honda, Nissan, Kia, TVs, and Others; however, I primarily specialize in Toyota vehicles.