Fuel injectors are supplied with pressurized fuel from the regulator. They will deliver the correct amount of fuel to the combustion chambers. This functions correctly because the regulator controls fuel quantity and pressure. However, a regulator can fail in the long term.
In this article, we will discuss the most common symptoms related to a bad fuel pressure regulator and what you can expect as the average cost of replacement.
How a Fuel Pressure Regulator Works
The fuel pressure regulator works by understanding how the driving conditions of your vehicle and how much fuel your vehicle requires are sent to the combustion chamber.
The fuel pressure regulator has mechanical diaphragms that are activated with a vacuum, which changes the fuel pressure for the required fuel to be delivered.
Some newer vehicles have an electronic fuel pressure regulator instead of a mechanical.
Top 6 Bad Fuel Pressure Regulator Symptoms
Having a working fuel pressure regulator is crucial in ensuring a smooth and consistent fuel supply to your vehicle. Without precise fuel pressure regulation, the delicate process of combustion that powers the engine will become disrupted.
Below are some of the more common symptoms that may indicate that you have a faulty fuel pressure regulator.
#1. Engine Misfires/Poor Acceleration.
An engine misfire and loss of acceleration power are the most common and obvious symptoms of a faulty fuel pressure regulator. You will be driving your vehicle, and it will lose power, stumble, and/or slow down all of a sudden.
Then, it may return to full acceleration power for a few moments before losing acceleration power again. You definitely do not want to put up with this type of situation because it can create a dangerous driving situation on the road.
#2. Spark Plugs Covered in Soot.
If you are in the process of determining whether or not you have a faulty fuel pressure regulator, you will want to pull out a spark plug to see whether there is a coating of black soot on the end of it. If there is, a faulty fuel pressure regulator is only one possible cause – others could be a generally dirty engine.
Also, be sure to check the ends of all other spark plugs to see if they also have soot on them. The soot that you found is from oil burning in the engine’s head. In this situation, you will want to install both the fuel pressure regulator and the dirty spark plugs.
#3. Black Smoke.
You should not see anything other than very little white smoke coming out of your tailpipe when you are warming your vehicle up. If you see dark grey or black smoke coming out of your exhaust, a faulty fuel pressure regulator can be a cause.
While there are many other possible reasons why you are seeing black smoke come out of your exhaust, it is most likely attributable to the fuel pressure regulator if you are seeing several of the other symptoms listed as well.
#4. Fuel Leaking Out of the Exhaust.
This is not very common, but again, if your tailpipe starts to leak gas, it probably means your fuel pressure regulator is bad and letting it happen.
A bad regulator can allow some gas to enter the car’s exhaust system, and it can end up leaking out of the tailpipe along with exhaust.
Before you really suspect this, make sure you don’t really just have water leaking out of the exhaust in condensation form. In this instance, the water is usually harmless.
#5. Fuel Inside Vacuum Hose.
One way to test and see if you have a bad fuel pressure regulator is to disconnect your vacuum hose from your fuel pressure regulator while the engine is switched off and see if you have gasoline in it.
If there is gas in the vacuum hose, you have a fuel pressure regulator leaking.
#6. Engine Won’t Start.
If you are trying to start your vehicle, and it won’t start because the engine will not turn over, chances are high that it’s a bad starter motor or a drained car battery. However, it may also mean something is wrong with your fuel pressure regulator.
Because the fuel pressure regulator is what controls the fuel pressure, and if the regulator is bad, it can cause low fuel pressure, which would prevent the car from starting.
When the fuel pressure regulator starts going bad, initially, you may be able to start the vehicle after multiple attempts. However, if the regulator is never replaced, eventually it will get worse to the point you can’t start the car at all.
How Much Will it Cost to Replace a Fuel Pressure Regulator?
The cost of replacing a fuel pressure regulator is primarily due to two factors. One, is your fuel pressure regulator a standard manual-driven regulator or electronic, and two, how difficult will it be to access?
Most of the time, the part will cost you between $50 to $200, but vehicles with an electronic fuel pressure regulator can easily run you double that amount.
In most instances, the fuel pressure regulator will be located in a fairly accessible spot, so the time it takes to replace it won’t require a lot of your time. Expect to pay in the range of $100 to $150 for labor (more if additional components, like the fuel rail, need to be removed too).
Overall, you can expect the total cost of a fuel pressure regulator to run between $150 to $350 in most situations, but for an electronic fuel pressure regulator, it can easily be over $500.
To save costs, it is always a good idea to have the work done through an independent mechanic or repair shop instead of a dealer.