Fuel leaking into vacuum line on fuel pressure regulator
1999 Silverado. Seem to be having fuel leaking into the vacuum line on the fuel pressure regulator. When you shut the truck off and pull the vacuum line off, it lets the fuel drip out. The truck sometimes is hard to start, it will roll over freely but doesn't catch for quite a few times, then it starts and bogs out for just a second and then runs fine. If I pull the vacuum line off and let the fuel out, then it starts fine for a time or two... Do I need to purchase a new fuel pressure regulator or what?
An expert who has achieved level 3 by getting 1000 points
An expert that got 10 achievements.
An expert that got 5 achievements.
An expert whose answer got voted for 100 times.
Re: fuel leaking into vacuum line on fuel pressure...
If you have fuel on the vacuum side of the reg, that means the reg is leaking,causing a variaty of drivabiliy problems. Replacing this reg is very straight forward. Just add a little lube to the O-ring on the reg before installation. Good luck.
Re: fuel leaking into vacuum line on fuel pressure...
Ok so heres what ya gotta do... get some and stick it in your mouth, flavor of your choice, and chew it until its really super duper sticky. then take it out of your mouth and put it in the hole where the fuel seems to be leaking from. good luck!
- If you need clarification, ask it in the comment box above.
- Better answers use proper spelling and grammar.
- Provide details, support with references or personal experience.
Tell us some more! Your answer needs to include more details to help people.You can't post answers that contain an email address.Please enter a valid email address.The email address entered is already associated to an account.Login to postPlease use English characters only.
Tip: The max point reward for answering a question is 15.
When you had the fuel pressure tested did it hold pressure with the key off or did the pressure drop off?
If it dropped off I would bet you have either a leaking fuel pressure regulator or a bad fuel pump. Fuel pressure needs to hold steady especially on a hot engine in order to prevent the fuel in the fuel rail from boil over.
I think the 99 has the external injectors. If it does the fuel pressure regulator is located on the drivers side of the engine about in the middle of the fuel rail. There will be a small vacuum hose attached to it. remove the vacuum hose and see if gas comes out. If it does the regulator is bad. If it doesn't I would check the pump next.
There is no charcoal filter on the return line or the pressure line. The charcoal canister is part of the evap emissions system and will rarely if ever effect the starting of the vehicle.
If it's not leaking fuel under the vehicle, the problem could well lie in a faulty Fuel Pressure Regulator.... If the rubber diaphram in the FPR becomes compromised, your described symptoms appear due to fuel leaking into the intake and not leaving the fuel line w/ injectors with enough initial pressure to instantly start the car.
Simply remove the vacuum line which is connected to the fuel pressure regulator then insert the key and turn to the "run" (not "crank") position. If fuel squirts out where you disconnected the vacuum hose, then this is definitely your problem.
You may have a leaky fuel pressure regulator located on the LH side of the engine on the side of the fuel rail. The internal diaphram can leak fuel which then gets into the vacuum line attached to the regulator. From there the leaking fuel travels through the line and gets into the intake manifold causing the motor to be slightly flooded when you restart it. The regulator is round, about 1-1/2" diameter, and about that long and has a small 1/8" vacuum line attached to it. After the engine has been off for a few minutes if you remove the vacuum line from the regulator and find even a trace of fuel in the line then you've found your problem. Typical symptoms for a leaky regulator are: Starts fine cold and will restart fine warm if the engine has only been off for a minute or so. Restarts hard warm if the vehicle has sat for several minutes or up to an hour. May produce a bit of black smoke during the warm/hard start.
SOUND LIKE FUEL FILTER STOPPED UP.WEAK FUEL PUMP.CHECK FUEL PRESSURE.IT SHOULD BE 60 TO 66 PSI.ALSO CHECK VACUUM LINE GOING TO FUEL PRESSURE REGULATOR.MAKE SURE ITS GETTING VACUUM.IF YOU GAS IN VACUUM LINE GOING TO FUEL PRESSURE REGULATOR.REGULATOR FAULTY.IF YOUR ENGINE IS 4.3 FUEL PRESSURE SUPPOSE TO BE EITHER 41 - 47 PSI AND 58 - 64 PSI
Remove the vacuum line from the fuel pressure regulator and inspect for fuel leaking into the vacuum line. There should be NO fuel.
The regulator is located on the upper intake manifold and is easily accessible.
Release fuel pressure by removing fuel pump relay and turning engine over to release pressure. Place a rag to catch any fuel under regulator Fuel pressure regulator has a locking clip pry clip off remove vacuum line pull regulator out with twisting motion,replace fuel pressure regulator install clip connect vacuum line install relay. Check for leaks,your done.
your fuel pressure is suppose to be 60 - 66 psi. first replace fuel filter.and check vacuum line going to fuel pressure regulator.make sure vacuum is going to vacuum line.if changing fuel filter dont help. fuel pump could be faulty.