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“I just replaced fuel pump car won’t start.” This is one of the complaints often made by drivers. But is it possible for a car to refuse to start after changing fuel pump? Well, this is 100% possible and we’re going to explain why shortly.
It’s a common problem for drivers to be stranded on the side of the road, with their car refusing to start. Some of the reasons that this could happen include running out of fuel, a bad fuel pump, having a dead car battery, etc.
In this post, we’ll tell you how to go about diagnosing whether it was truly your fuel pump that caused you trouble, as well as what steps you need to take in order to tackle the problem.
What Is A Fuel Pump?
A fuel pump is a component in motor vehicles that transfers liquid from the fuel tank to the carburetor of the internal combustion engine.
A fuel pump is powered by the engine’s crankshaft, either directly or indirectly. When there is no fluid to send through the system, it will not work at all, a common problem in vehicles with electric pumps.
It takes between 12 and 15 pounds per square inch (psi) of pressure to activate a typical automotive fuel pump, and the fuel pressure must be at least 17 psi in order to provide adequate amounts of fuel for most engines.
A malfunctioning fuel pump may allow air into the system and/or leak trapped gas from a faulty seal. A fuel pump is usually located in the fuel tank of a vehicle, and when it fails or malfunctions, it can cause problems ranging from an engine stall to total system failure.
Fuel pumps are often inaccessible for repair so they must be replaced as soon as possible.
Can Fuel Pump Cause Car Not To Start?

Yes, when the fuel pump stops working, it can lead to your car not starting. Basically, if the fuel pump completely fails to the extent of being unable to provide enough fuel for the engine to run, the vehicle will not start.
Can Car Refuse To Start After Replacing Fuel Pump?
Yes, it’s a common problem for a car to refuse to start after changing the fuel pump. This can be caused by worn-out electrical connections between the wiring harness and fuel pump relay or connection at the fuel pump, or a faulty fuel pump module.
It’s also possible that the fuel pump installed on your car is not good enough, perhaps it has some factory fault upon purchase.
It’s also worth noting that your car refusing to start after changing the fuel pump could also be a coincidence and has nothing to do with the fuel pump. There are other things that can make a car not start, such as:
- If your car is old and has been driven for years without being serviced
- If there are other malfunctions within the vehicle’s engine
- If your car battery is dead
- Etc.
But what should you do in this case?
What To Do When Your Car Won’t Start After Replacing Fuel Pump
The most important thing you can do is stay calm and assess the problem calmly.
You should check all of these things:
- Make sure there is enough gas in the tank (if necessary, add more)
- Make sure that it isn’t just a loose connection or ignition problem (try to start the car again)
- Make sure the fuel pump relay is not faulty.
If all of these things fail, you’ll need to take it to your local mechanic for further diagnosis and repair, which may also mean replacing the fuel pump again.
Some people might argue that this may be due to an electrical fault in the wiring harness, which is where the relay is situated.
But probably, it’s just a loose connection (less likely) or an ignition problem that has nothing to do with the fuel pump itself.
In this case, your car should start again after you have tightened all connections and checked the spark plugs on both cylinders of your vehicle. You may also need to replace the ignition coil.
Conclusion | I Just Replaced Fuel Pump Car Won’t Start
You already know that it’s possible for a car not to start after replacing fuel pump. Now, if you ever found yourself in this kind of frustrating situation, the best thing to do is to check all the possible “car not starting” causes outlined in this post.
If everything else is in order, your best bet will be to consult with your auto mechanic to diagnose the problem. If he’s the person that replaced your fuel pump, he should check if it was properly installed and if the installed fuel pump is actually in good working condition.
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