Car Engine

6 Common Fuel Pressure Regulator Symptoms You Need To Check Know!

Mike Cross
Updated Feb 16, 2022
How To Know When Fuel Pressure Regulator Is Going Bad

Cars have many parts that have to work right for them to keep running. Most people know that the engine needs gas, air, and a spark to ignite. Also, most people know that the battery is an essential part of a car and often is the problem if the car won’t start.

What if your car isn’t running right though? Well, the fuel pressure regulator might be the issue if that is the case. After reading this you will know the signs of a bad fuel pressure regulator, so you can check yours if you are having any of these issues.


What Does Fuel Pressure Regulator do?

The fuel pressure regulator is responsible for making sure the pressure in the fuel system is right. This is because the fuel system is under pressure and when the engine combusts it moves pistons generating power to the wheels.

If the pressure is not what it is supposed to be in the fuel system, then the explosion may be too strong and damage the engine, or it may be too weak and not generate enough power. This is why it is essential to stay on top of making sure your fuel pressure regulator is working right.

The regulator comes in multiple forms depending not the type of car, but no matter what kind your vehicle has the signs of bad ones are universal across pretty much any car.

The main characteristics are the engine not running smoothly, black smoke coming from the tailpipe, gasoline leaking from the exhaust, stalling the engine, issues when decelerating, blackened spark plugs, oil smell on the dipstick, and gasoline in the vacuum hose.

I know there are a lot of different signs, but we will go into detail of each one, so you precisely know what to look for.

6 Common Fuel pressure regulator symptoms

How To Know When Fuel Pressure Regulator Is Going Bad
How To Know When Fuel Pressure Regulator Is Going Bad

1. Engine not running smoothly

If your engine is not running right, then it is a good chance that it is the fuel pressure regulator. Odd sounds while dealing or when you first start your car before putting it in gear might indicate a bad regulator. To troubleshoot more, you can change the oil filter and see if issues continue.

A stalling engine is also a sign that it might be the fuel pressure regulator. If you go to accelerate and the vehicle takes a second before it starts to go, then you should check your regulator out. A car should start moving as soon as you hit the gas pedal. There should not be any waiting, and if there are issues accelerating even if slightly, then you should have your car checked out.

The same can be said when you decelerate as well. If the engine backfires or smells like gas when you are slowing down, then it might be a sign of built up gas in the engine. This built up gas can come from a bad fuel pressure regulator. Even slight issues need to be taken seriously because significant damage can occur to your car if the regulator is going bad.

2. Black Smoke From Tailpipe

So now that we have covered some of the different engine signs, we can get into other symptoms that don’t come directly from the engine.

The first of those is black exhaust. Black exhaust is a sign that something is wrong with your car and things need to be checked out.

A lot of times it is the fuel pressure regulator when the smoke is black.

This is because there is too much fuel going to the engine and soot is being made turning the smoke black. Car exhaust should be white or gray. If it is black or any other color, then you should have your car checked out. Using bluetooth obd2 scanner can generate code P0089, it's code for a fault found with the fuel pressure regulator.

Read more: What Are The Best Bluetooth OBD2 Scanner In 2022?

3. Gas Leaking from Tailpipe

Checking Gas Leaking
Checking Gas Leaking

Another sign from your tailpipe that the fuel pressure regulator might be going wrong is if your car drips gas.

Sometimes this can be confusing because your vehicle might drip water if you have been using the AC, so you might have to smell the liquid by the tailpipe to see if it is gas or not.

If it does smell like gas, then this means the regulator needs to be checked.

That is because too much gas is going to the engine and not all of it is being burnt.

That is why the residual gas is leaking from the tailpipe. If you see any liquid dripping from the exhaust, then you should investigate and make sure you know what it is and why it is happening.

4. Dipstick Smells like Gasoline

There are a few other parts of the car and engine that you can check to confirm more that it is a fuel pressure regulator issue before taking your vehicle in somewhere.

You can check your oil dipstick and make sure your oil is the right amount and the right color.

Also, check the smell of the oil. If it smells like gas, then that means the pressure regulator is letting gas leak into your oil system. This is not good and a sign that it needs to be changed.

5. Stalling Spark Plugs

Spark plugs lie on gloves
Spark plugs lie on gloves

You can also check the spark plugs to see if it is them causing the stalling issues. If they are blackened, then it is a sign that the fuel pressure regulator is not working right. If the first plug you check is sooty, then check the rest.

It might just be that head that is burning oil. If only a few plugs have issues, then the problem might be something else.

Also, if your plugs are old, then it might just be because of that that your engine isn’t running right.

One last tip is if you change your fuel pressure regulator, then you probably want also to change your plugs, so you know that they are fresh and new. This way if more issues come about you know it isn’t from old plugs.

6. Gas in Vacuum Hose

Lastly, you can check the vacuum hose to see if it has gasoline in it.

You might want to let a mechanic or someone else do this if you aren’t too experienced with cars though because you want to make sure the system stays under pressure properly.

If there is gas in the hose or if you turn the switch on and fuel drips out, then you have a bad fuel pressure regulator.

This is a sure fire way to know if that is the issue because the hose is connected right to the regulator.


After reading this, you should understand the importance of the fuel pressure regulator and also a lot of signs of one failing.

If your vehicle has any of these issues, then you know where to start on checking things out.

A bad fuel pressure regulator needs to be caught early to prevent damage to your engine. That is why waiting for a check engine light may be late and if you have any of these symptoms you need to take them seriously and see what is causing them.

Mike Cross
Life is too short to drive with stock audio

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One comment on “6 Common Fuel Pressure Regulator Symptoms You Need To Check Know!”

  1. Thank you for your help! My Toyota ceilica 1994!! 1.6.Litter. is hard to start? Acked like if it was a carberatora?? It was fliuded?? Then 2 hrs later when it started? It went to smoke? Then it would not ideal? And was running ruff! So I took fule presher regards ? When I took vacuum line off? Was full of gas! Thank you!!

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