How to Check Fuel Pump Pressure

Checking on the pressure of the fuel pressure is crucial when detecting an issue in the engine performance. If there is low fuel pressure, it can lead to all kinds of problems in engine performance problems like a hard time in starting, minimal power, low level of emissions, and also bad gas mileage. If this gets ignored too long without any treatment, the computer is going to consider this as lean.

Depends on how it was applied, it does not take long to install a gauge for fuel pressure. There is a test port in most of the fuel rails where the tester can easily be screwed so you can get a reading of the fuel pressure. There are some that require you to use the fuel filter and install a gauge in the fuel pressure in between the two to get the fuel pressure’s condition.

There Are Cranks In The Engine But Refuses To Start

If the fuel pump is dead, it is going to take a while before the engine starts, but it could also be an ignition system issue or problem with the engine.

What you need to check on at first is the spark. This is possible by connecting a tester for spark plugs to a plug while there is a crank in the engine. The tester should be firmly linked to the engine block to have a concrete electrical connection.

If you see a coil-on-plug system, you can remove one coil. You can do this and then put a spark plug at the tail end of the coil. After that, position the coil and plug so it will touch the engine’s metal part.

If you have a working ignition system, there should be a chain of sparks that you will see while the engine is being cranked. If you don’t see any spark, it means that there is a problem with the ignition like if the position of the crankshaft sensor is bad.

After that, check the belt’s timing if there are an overhead camshaft and rubber timing belt in the engine. Normally, the belt can be found in a plastic cover at the tip of the engine. Unscrewing the cover and moving the cover back will allow you to see the belt. Check how the belt looks and if it looks fine, and it turns while you are cranking the engine, you have no issue with the compression.

The timing belts have the tendency to skip if they become loose or the cogs are damaged. It can also be an issue for the camshaft overhead to stop if the engine does not have enough oil or has overheated. Although, if the cam gear rotates while the engine is cranking, that may not be the problem.

How To Measure The Pressure In The Fuel Pump

Depending on the application, it needs between 30 to 80 psi of fuel pressure so it can start running. Remember that fuel injected engines have a high sensitivity to fuel pressure. If the pressure at the fuel rail’s engine is a few pounds less than the specifications, there is a possibility that the engine will malfunction, or experience stalling problems.

Specifications in the pressure will vary depending on the kind of fuel injection system and performance, fuel economy and emission requirements of that certain vehicle. There are no set rules for this. Each application varies so always consider the pressure specs when you need to troubleshoot the performance problems that are involved with fuel performance.

If there is too much pressure in the fuel, the engine is running thick. This leads to an increase in consumption and emissions of carbon monoxide (CO). An engine that runs rich may become rough, surging and also carbon-fouled spark plugs.

If there is a lack of fuel pressure, the engine may not start. If it does start, it may run poorly and idle roughly. The lack of fuel pressure causes a lean fuel condition that leads to lean misfire, rough idle, hesitation, and misfire during acceleration.

How Else Can You Check?

Another way to see if the fuel pump failed is to check a number of amps it is pulling. You would need a voltmeter that comes with an amp setting, a voltmeter that has an amp clamp or lab scope. You have the option to clamp around the power wire towards the fuel pump or you can include a jumper instead of the fuel pump fuse and use a clamp around the jumper wire so you can get the reading of the amp using your voltmeter.

You would have to check this while there is a crank in the engine or when there is a running fuel pump. There are certain vehicles that allow the fuel pump to be removed and the hot wire in the jumper to the relay of the fuel pump to the feed wire or from the fuel pump relay towards the fuel pump and you should see the fuel pump running.

The amount of amps that the fuel is going to pull is dependent on the fuel pressure that your fuel pump should deliver to the fuel rail. Another thing to consider about this test is the 14 to 15 psi to 3 to 4 amps and 40 to 50 psi to 7 to 8 amps.

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Controls In The Computer

The PCM needs to have the right information coming from its sensors to find out how long before the fuel injectors start to work. Inspecting codes and data using a scan tool can help in identifying which sensor has the wrong information. Having the ability to effectively use the scan tool needs careful study and enough practice. It gets easier as you get accustomed to using it.

You always have to check the fuel pump pressure to avoid any inconveniences while on the road. Also, be careful about touching the spark plug because you can get shocked. Just follow everything in this post so you won’t make a mistake while checking your fuel pump pressure.

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