Possible fuel issues please help
The damper on the fuel rail has a reference, but that device isn't a pressure regulator and the PCM assumes a constant 58psi (assuming constant voltage).
If you have a pressure regulator running w/ vacuum control, I'd try removing and capping the vacuum source.
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TECH Senior Member
Joined: Apr 2002
Posts: 6,080
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From: So.Cal.
What is your rail pressure with the reference hose removed from the FPR (at idle or at any rpm)...?
Have you noticed any gasoline inside the reference hose...?
When did this start to happen...?
Have you noticed any gasoline inside the reference hose...?
When did this start to happen...?
Rail pressure is 55-60 with it removed 40-60 with it on, never say any gas where it wasn't supposed to be, and it started last Friday but has done it before but always cleared up in a short time
As I said previously:
The damper on the fuel rail has a reference, but that device isn't a pressure regulator and the PCM assumes a constant 58psi (assuming constant voltage).
The symptoms and error code you're seeing are indicating lean air:fuel ratio.
Your regulator is reducing fuel pressure at high vacuum periods, which would reduce the volume of fuel delivered...causing a lean air:fuel ratio.
So remove and cap the vacuum signal to your fuel press regulator and re-test.
I'll try and see, according to the instructions that came with my rails and regulator the reg needed to be plugged into a vacuum source on the intake so that's why I did it.
Other systems like the older TPI had vacuum-modulated fuel pressure and they were calibrated in software accordingly. Not the case w/ LS1s.
I think you'll be happy w/ the vacuum removed and capped from your regulator.
I tried it, it helped but it still is doing it(SOB) I have a video and some pics of my setup to help get a idea. The pressure guage is on the rail if that helps, about how far should the fuel line push gas out on it's own? I'm thinking it may have blockage or a bad seal in my regulator. But Im loving the help you guys are offering Thanks a load
You definitely need to find and fix the cause of your remaining fuel pressure variation. The red MSD ignition coils have many reports of failure and you'll want to keep an eye on them, but they don't cause fuel pressure problems so put them on the back burner.
If your fuel pressure continues to fluctuate w/ the vaccum signal disconnected and capped, I'd say it's time to get scan data. It's possible your voltage is fluctuating and causing the fuel pump to intermittently underflow but no way to check that over the Internet.
If your fuel pressure continues to fluctuate w/ the vaccum signal disconnected and capped, I'd say it's time to get scan data. It's possible your voltage is fluctuating and causing the fuel pump to intermittently underflow but no way to check that over the Internet.