I hear a Whirring noise when the vacuum line is hooked up to the fuel pressure regulator and the engine is at idle. Give it just a little gas the noise goes away. I am not getting any codes and the car is running fine whether the vacuum line is hooked up or not. The noise is loud enough to be irritating. The sound is whirrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrr just hold the "R".

I checked my fuel pressure. With the vacuum line hooked up I get 44 lbs running at idle. If you rev it up it will dip to 42 for a second then go up to about 50. If I disconnect the vacuum line I get a constant 52 lbs no matter what I do. The book says the pressure should be 48-55 lbs.

I changed the fuel filter today and the noise got a little quieter. Say the volume was 8 before. The filter swap turned it down to a 6. The fuel pressures did not change at all after the filter swap.

Is the regulator messed up? I can't say for sure but I think the sound is coming from it.

Or have I got a fuel pump on the way out?

As I understand things; the purpose of the vacuum line is to lower the fuel pressure at idle to prevent a rich condition when less fuel is needed. I ran it disconnected the last two days. I checked my long term fuel trim numbers with my Actron 9180 and they were positive 1 and 4. As I read the manual a positive number means the PCM is correcting for a lean condition and it can correct up to 20% lean or rich. Is there in harm done in just disconnecting the vacuum hose and plugging it?

 

Well I fixed it. Since no one responded I decided to change to Fuel Pressure Regulator. That was it. Just thought I would let people know in case someone else has this problem someday.

So many post here start with someone asking for help then getting advice but the original poster never comes back and says if he ever go his problem solved and what solved it.

 

Thanks for posting the solution. I didn't reply because I didn't see the thread.

 

Was this on a 3.4 or a 3.8?

 

This was on a 1999 3.8 but I think it would apply to either.