In our previous post, we have questioned the widespread problems after altering a fuel pump. One of the common worries is a difficult begin, probably because of having actually low to no fuel push. To diagnose this, you need to meacertain the fuel pressure by utilizing a gauge.

You are watching: How to check fuel pressure without gauge


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But what if you don’t have actually a gauge and also you deserve to only inspect exactly how tough the fuel pump is working? In this write-up, we will attempt to answer this question.

How to Check Fuel Prescertain Without Gauge

A fuel pressure gauge is a critical tool for diagnosing low fuel pressure. A weak pump that isn’t transferring enough pressure deserve to reason an engine to run lean,misfire, and also hesitate once speeding up. However, what if you don’t have actually one and also desire to inspect the pressure?

There are 2 choices just how to examine fuel pressure without a gauge. You can actually inspect fuel push through OBD 2 scanner, which will certainly give you readings from the fuel press sensor. If you don’t have actually a scanner, you deserve to listen to a buzzing sound as soon as you attempt starting your vehicle, which shows that the fuel pump puts pressure on the mechanism.

Using a diagnostic code reader

As stated over, if you don’t have actually a fuel pressure test kit, you can usage an OBD-II diagnostic code reader to examine the fuel push.

However before, it just applies to more recent cars via fuel pressure sensors that continuously monitor the fuel pressure across the fuel injectors.

If a auto was made in or after 1996, it is OBD 2 compatible. However before, the number of parameters will depfinish on the certain OBD 2 protocol of your auto.

Some gasoline engine fuel injection units have actually pressure sensors that have the right to be observed via a diagnostic sdeserve to tool.

Although it cannot provide you the actual fuel push readings, Diagnostic Trouble Codes have the right to aid you diagnose if the difficult start is due to low or high fuel press.

What you’ll need:

An OBD II Scanner preferably via live information capability.

Tip by Step Instructions:

Tip 1. Start your engine and let it idle for several minutes.

You have the right to additionally take your automobile for a brief 10-minute drive to warm up the engine. This will stop any difficulty through fuel push readings that typically arise from cold engines.

Step 2. Connect the scanner to your OBD 2 port

To discover the port describe your owner’s manual. It is usually situated under the steering wheel and also over the pedals.

If you are utilizing a generic code reader or scanner, you deserve to usage the OBD 2 pin found in your vehicle’s engine bay.

Step 3. Pull-out Stored OBD-II Error Codes

If there is a problem through fuel shipment, the diagnostic scanner will certainly display screen one or even more stored OBD-II trouble codes in the “P” series.

Here are some widespread OBD 2 error codes you’ll see:

1. P0087 – “Fuel Rail/System Prescertain – Too Low”

P0087 is a general code that suggests a difficulty in the fuel distribution device. It is motivated as soon as the ECM has actually detected low fuel press at the fuel push sensor.

It is equivalent to P0088 which tells us tbelow is high fuel press uncovered in the fuel mechanism.

2. P018C – “Fuel push sensor “B” Circuit Low”

There are a couple of things that can reason this code favor a negative sensor, or high or low fuel pressure.

3. P0191 – “Fuel Rail Pressure Sensor Circuit “A”

It suggests a potential abnormality in the fuel rail press readings. Several mechanical and also electrical issues have the right to cause the P0191 code including low or high fuel press.

Tip 4. Check The Live Fuel Prescertain Data

If the error codes don’t show a trouble through fuel pressure, you have the right to monitor the live fuel press data on your scanner. However before, not all OBD 2 scanners have this capability.

That’s why you must inspect the compatibility prior to buying one.

If your diagnostic reader supports real-time data, then attach and also enter the engine DME diagnostic mode through a analysis of the current parameter. After the analysis is complete, select thefuel delivery systemalternative.

This option will display you the fuel rail press setallude, which is the optimum fuel push on the fuel rail as soon as the engine is running. You have the right to usage it to compare via the live fuel push worth.

If the worth remains the same also after revving, then there is no problem through the fuel pressure.

However before, if tbelow is a distinction between the two values or you enrespond to any type of concern while revving, you should inspect your fuel press and also see why it is fluctuating.

You have the right to use an OBD II shave the right to tool to read out live data and monitor the fuel rail pressure in real-time. If the value continues to be the same while revving at 1500rpm as much as 3000rpm, then the fuel pressure is fine.

However before, if the readings readjust at a details RPM selection, then the majority of most likely there is a problem with fuel push.

2. Testing for fuel pump buzz

So here’s the scenario, you don’t have actually either the gauge and diagnostic tools to watch the press, neither you have access to it.

What can you do? You still must recognize if your fuel pump is functioning properly.

Well, there is still a way just how to examine fuel push without a gauge or an OBD II scanner.

What you’ll need:

A sharp ear

Tip by Step Instructions

Tip 1. Turn your vital from OFF to ON for the fuel pump to turn on.

Step 2. Listen for a buzzing sound as you turn the tricks ON.

If you hear a buzzing sound, then this implies your fuel pump is working fine. That’s your fuel pump priming.

To ensure a solid charge of fuel is pumelted via, the fuel pump pressurizes the fuel in the lines leading to the injectors.

Tip 3. If you don’t hear a buzzing sound, it’s a signal that tright here is somepoint wrong with your fuel pump.

It might be a relay switch that is not working, a blown fuse, or a corroded or disassociated wire, or worst the fuel pump needsreplacement.

Can you examine fuel press via a tire gauge?

Do not usage a tire pressure gauge. Tright here has been a conflicting watch on this yet in the majority of cases, the Schraeder valve in the test port is also deep to be depressed by a tire pressure gauge.

In addition, tbelow would be inaccuracies bereason a tire gauge is expected to measure air push and also not liquid press.

To complicate matters, there might not be a place for the vacuum to escape and also obtain trapped in the gauge.

Fuel gauges have actually a bleeder valve that gets rid of any type of air inside, however they additionally have actually lengthy lines for air to work out. Finally, the gasoline will probably damage the tire gauge.

See more: Why Did The United States Encourage Panama’S Declaration Of Independence From Colombia?

How to examine fuel push without a Schraeder valve?

In this video from Phillips Vision you will certainly check out exactly how to inspect fuel push on a car that DOES NOT have actually a Schrader valve. This verified this on a 2005 Dodge Neon SXT 2.0L using a Fuel Pressure kit purchased at Harbor Freight Tools.