It is not all sunshine, lollipops, and rainbows when you try to change your car’s fuel pump. You have to be pretty careful with what you are doing and ensure your new fuel pump is compatible with your vehicle because one mistake could make you end up facing common problems after changing fuel pump than it solves.

So before you panic and question, “Why is my brand new fuel pump not working?“, you may want to check out our article first. In this guide, we will discuss various problems of fuel gauge not working properly after changing it, how to fix it, and much more.

So get ready with your tool kit!

What Is A Fuel Pump? Is The Replacement Important To The Vehicle?

Have you thought about how the fuel you refill in your car tank gets to the engine?

Well, it is the fuel pump that works as the link between the two. And once it stops functioning, it either needs replacement or a fuel pump repair.

But is the replacement necessary?

If there is no fuel pump replacement, the engine won’t get a fuel delivery. It will either let your vehicle stall or you will have poor fuel mileage.

Thus, fuel pump replacement or repair is necessary.

Now, you must be asking, “What are the symptoms of having air in the fuel line?” Or “Why does the new fuel filter not work?”

Head to the next segment to find the main culprits.

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Common Problems After Changing Fuel Filter Or Pump

Some car owners often wonder, “What would cause a new fuel pump to go bad?” Some even report that their newly replaced fuel pump is not working, while others experience inconsistent fuel gauge readings, hard start, or rough idling engine.

It could be a result of a bad fuel sending unit, incompatible aftermarket pumps, or a result of incorrect installation. Well, the reasons are plenty.

Below we have explained each problem related to the newly installed fuel pump and its causes. So read on…!

1. Engine Runs Roughly After A Fuel Pump Change

Many complain that their car idles roughly after adding a brand new fuel pump. Well, this issue occurs due to the engine being starved of fuel. Here the villain is improper installation of the fuel pump, and there could be problems with the wiring harness. And this would stop your fuel pump from getting power.

2. Hard start or no fuel pressure after installing fuel pump

The second culprit after replacing the fuel pump could be a hard start. It happens when the vehicle cranks for about 1 minute before starting due to no fuel pressure but the pump works fine.

If there is no fuel pressure, it will cause the engine to stop running.

3. Fuel pump is not working

Sometimes, a fuel pump is installed upside down which can cause errors, and it won’t get enough power to run or start the engine. Plus, it may even leak from the bottom of the car tank. 

The most common reason for this problem occurs because of a wiring harness coming in the way. The fuel pump connector gets installed in an opposite way which can cause the fuel pump to go into the engine.

4. Inconsistent reading

Your gas gauge sometimes reads full or empty or bounces back and forth. If this is happening with you as well, then the fuel sending unit is the main villain.

5. Fuel gauge does not work after installing fuel pump

If your gas gauge is not working after replacing the fuel pump, it could commonly happen if you are using an aftermarket sender that is of cheap quality.

6. Difficulty starting 

Fuel pump tends to deteriorate and wear out over time. Even though a weak fuel pump supplies the fuel, the car will experience difficulty starting due to less pressure. 

Sometimes, a weak fuel pump may crank a lot before starting, and in certain situations, the car may need multiple turns of the key before it will start. So instead of replacing the pump, it’s a great idea to check for low pressure or a blown fuse in the fuel line.

7. Engine Stalling at High Temperature

Staling can happen due to various reasons, and the main culprit here can be the fuel pump motor.

If this happens frequently, it can increase the temperature gauge and deteriorate the fuel pump. It means the fuel needs a quick replacement. 

Are you wondering, “How to fix a fuel pump without replacing it?” Then, the next section will give you the right answers.

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Top 5 Ways On How To Start Car After Replacing Fuel Pump

Are you puzzled and thinking, “What to do after replacing fuel pump?” Or do you wanna know how to troubleshoot or check common fuel pump issues?

Since a mere fuel pump can cause havoc in your life because it is linked to various possible causes, including wear, faulty wiring, etc. If this happens, it becomes necessary to identify the root cause and fix the exact problem.

So, let’s check out five fixes on how to start the fuel pump after replacing it.

If you have other problems like “no fuel pressure but pump works“, you can still just read this section if you have missed anything important.

1. Fuel Pressure Test

Acceleration issues can be caused by clogged fuel filters.

• So first of all, remove the filter and drain the leftover fuel.
• Now, insert a short rubber hose into the filter inlet and blow it. Next, reinsert the filter.
• Afterward, get a fuel pressure gauge and connect it to the fuel pump test point. Next, take help from someone to rev your engine while you check the reading of the pressure gauge.
• It should read something close to your car repair manual’s specifications.

2. Use Fuel Pressure Gauge

A fuel pressure gauge can keep an eye on to ensure it is functioning at peak performance levels. Moreover, it monitors the fuel pressure in the car engine to prevent any damage to your injectors and fuel pump.

It is one of the best solutions when you are looking for ways to work on your fuel pump to start the vehicle. This method is used by most technicians when there is a fuel pump issue. So yes, this fix is another relied upon a remedy. 

What to do?

• Attach the fuel pressure gauge to the engine of the vehicle.
• Doing so will help you to start your vehicle and give you an idea about the failing engine.

3. Fuel Pump Electrical Test

One needs to check the power source, which is the fuse of the fuel pump. The location of each fuel pump fuse is different as it is based on vehicle models and types.

Check the manual of the vehicle to locate where it is situated. Once you find it, you need to pull it out to see if it is burned or broken. If you spot no damage or it is not blown, have a look at other fuses that are connected to the fuel pump system.

After checking out the fuses and if everything looks fine, then call someone for help. Tell them to start the vehicle (put it in ignition), and you can try to listen to the click of the fuel pump.

Does it seem too technical for you?

Then you can ask a professional to run a test for you.

4. Applying Some External Pressure

The next tip for a bad fuel pump is to put some external pressure on the vehicle. The main issue with the fuel pump is that it lessens the needed pressure for the operation of the vehicle, and that causes a decrease in its performance. 

So the best solution is to apply external pressure to maintain the pressure level of the car engine to perform. 

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5. Maintaining The Engine’s Heat

This is yet another possible reason to start your vehicle with a bad fuel pump. The cause why your vehicle starts even though the fuel pump is bad is due to – 

Once the vehicle gets cool, the fuel pump resets itself without the need for heat and pressure.

As a result, it disrupts and malfunctions your vehicle’s performance. Wanna know the right way to start your car with a faulty fuel pump?

Well, it is to maintain a significant amount of heat in the engine of your vehicle. Doing so will reduce the malfunction in the vehicle and stabilize the car’s performance.

Frequently Asked Questions

Let’s check out some commonly asked questions related to fuel pump replacement and more.

1. What happens when you wire a fuel pump wrong?

If the fuel pump isn’t installed in the right way or correctly, it won’t be able to supply enough fuel to the engine or it won’t work properly at all.

And when your fuel pump is not working correctly, your engine won’t get the right amount of fuel which helps it to function right. Thus, your engine will lose fuel efficiency and power. It can cause many such serious problems and upset you even more.

2. Does a new fuel pump need to be broken in?

No, there is no break-in period for a fuel pump. There are high chances that your fuel pump is totally fine, and you are just making too much power.

You might be also pushing the single pump to the max speed, and thus, it is facing issues while trying to keep up with your fuel demands. So yes, breaking in a new fuel pump depends on how severe your problem is.

3. Can a fuel pump be installed wrong?

Yes, we are sure that you can sometimes install a mechanical fuel pump wrong. It is because you are not a professional, lack manuals and online resources, and do not have much knowledge of step-by-step instructions and pictures, so there is a high chance of missing out on any small steps while installing the fuel pump. This way you won’t be able to accomplish the task at hand.

Key Takeaways For Most Common Symptoms After Changing Fuel Pump

In this blog, we read that the most common problems after changing fuel pump resulted due to incompatible parts and improper installation. So it is better to know how to install the fuel pumps properly.

Honestly, problems related to fuel pumps can be complex, and replacing them on your own is yet another tiresome task that needs strict care.

If everything fails, or you don’t want to get entangled in a stressful scenario, then you should take assistance from a professional mechanic or an experienced technician.

Furthermore, if the problem occurs due to a faulty part, then make sure to carry a receipt as a backup to get it fixed or have it replaced under warranty. For more technical guides, keep checking back with your website regularly.

Good Luck!

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