Fuel pressure regulator keeps going bad

Hi,

That is a very good question. By chance, are you purchasing original GM parts or is it something aftermarket? Were both of the new regulators the same brand?

Also, with the engine running, is there a vacuum to the vacuum hose at the regulator?

Let me know.

Joe

Hi,

Where is the fuel coming from into the airbox? The vacuum hose should run to the engine intake.

Next, the fuel system has a return line to the fuel tank. If the problem continues, I'm questioning if something has plugged the return. However, since it ran well for a few trips, I'm even questioning that. If you look at pic 1, it shows the fuel lines. The highlighted one is the return.

As far as the regulator is concerned, it's a very simple design. The fuel pressure regulator is a diaphragm relief valve. The diaphragm has fuel pressure on one side and regulator spring pressure on the other side. The fuel pressure regulator maintains a constant pressure across the fuel injectors under all operating conditions. If it keeps failing, either we have poorly made regulators (which may be the case), or there is extreme pressure being built that it can't handle. That doesn't make sense to me yet, but anything is possible.

Let me know if the new one takes care of the issue. If it doesn't, return it and get your money back. Get one at a parts store manufactured by a well-known company. For example, Delco, Standard, and there are many others are well known for what they do. Often times when you get parts from online, it's difficult to tell where they came from.

Keep in mind, this is a theory at this point.

You know, I didn't realize how expensive they are for this vehicle. I did a little research for you and found a few on rockauto. Com that I recognize. I attached it in pic 3.

Let me know what I can do to help.

Take care,

Joe

See pics below.

Hi,

As far as the pressure, if it has no escape, it will build. The system has a return built into it.

The fuel pump sends pressure to the injector rail. The regulator is supposed to release the pressure when it reaches a specific point, allowing the unused fuel to return to the fuel tank. If there is no place for it to go because the return is plugged, the regulator can't do its job simply because there is no place to release the fuel. So, it will continue building until it "potentially" break the regulator.

If the new regulator doesn't help, we need to disconnect the regulator, open the fuel tank cap, and see if you can blow compressed air (low psi) through it confirming it isn't plugged. If it is, it will require the removal of the return line for inspection and to locate where the problem exists.

Please understand, at this point, this is a theory. All part of troubleshooting. Sometimes I drive myself nuts thinking ahead. LOL

One thing, is it possible for you to take a pic of the hose filling the airbox with fuel and upload it for me to see? Where does the opposite end of that hose go to? For some reason, I can't picture how fuel is getting to that point.

Take care of yourself. And, hang in there. We'll get it figured out one way or another.

Joe

Hi,

You are very welcome. Today's vehicles can drive anyone crazy. LOL No pun intended. LOL My confusion is there should be one vacuum to the regulator that then goes to the intake manifold and not the airbox. That is where I'm getting confused. I even went through different manuals, and they are showing me the same. Sorry, not being there makes it a bit more difficult. I was thinking maybe I was missing something.

Take care of yourself and I'll watch for your reply.

Joe

Hi,

Let me see the pic when you upload it. That way I'll know for sure. However, I suspect it is the black plastic intake manifold you are referring to.

Take care,

Joe

Yep, that's part of the intake manifold. That makes sense to me.

Joe

Hi,

The only thing I can think of is somehow the vacuum in the airbox was drawing it in somehow.

Let me know if it continues to work properly. I'm interested in knowing. However, I have a feeling the parts were faulty.

Take care of yourself and I look forward to hearing from you again.

Joe