olcurt

After having some starting difficulty and finding a vacuum leak at the fitting I replaced my fuel pressure regulator and the fitting on my 5.3L 2000 Silverado. It starts better now but when it is cold outside I have a lot of noise\vibration coming from the regulator. The vibration travels down the fuel line causing it to vibrate against the frame.

Any idea what might cause this?

jkgray80

Have you checked your fuel pressure tosee if it ispulsing?When you say 'fitting' do you mean the vacuum line?

olcurt

Not sure how to check the fuel pressure or if I have the equipment to do it. I replaced the little boot that connects the vacuum line to the regulator. It was cracked.

jkgray80

No offense, but if you are unsure about working on a fuel system ,take it in.
You would need to by a pressure gauge. Schrader for gauge hook up is on P-side.
Should be 50-60psi on idle.

olcurt

If I had the gauge I could probably do it. Didn't realize there was a schrader valve present for this.I could probably find the procedure in a manual and go thru the process of releasing the pressure and doing the check.

I had it at a mechanic shortly after replacing the regulator as it was still starting slow on occasion and was occasionally making the vibration, but it was still warm outside then. I have to admit, I didn't find the small oring from the original regulator when I took it off. I thought maybe I just dropped it. I looked inside the hole with flashlight and reached in with a small screwdriver and couldn't pull anything out. The regulator seems to fit very snug. Is that normal? I may try to take a small pick and see if that old o-ring is still in there. I guess it just doesn't make sense that it runs fine when the weather is warm, but vibrates/pulses when cold, unless the sensors are calling for a richer setting and that triggers something related to the vacuum and thus the regulator.

It started making the noise and vibration after replacing the regulator. The mechanic replaced a fuel pump and checked fuel pressure before and after. By the way,I found the split vacuum fitting after the mechanic worked on it, and may or may not hae needed the fuel pump! I had also replaced plugs and wires prior to this.

By the way, no offense taken. I'm 51 and much more familiar with older systems. I'm currently rebuilding a 66 Chevy pickup that was my grandpas, so I can turn a wrench, but am not up to par on modern systems.