Weird fuel pressure readings.

[Turbo6Smackdown]

Ok, I just changed my FPR over and started er up. Everything looked good. Shut er down, and the FP went to 40 and held; for about 30 seconds, then slowly over a course of about a minute faded to 38, then in another minute 36 and stayed steady for about 10 minutes. Checked back and it's now at 42. How did it go back UP. And, how long's the standard for it to hold pressure for? And how many PSI should I be expecting it to hold?

 

[LEGACY_GN]

I just checked mine. It's at 20 after half an hour. When I turn the ignition on it goes to about 45 when charging the lines then drops to about 40 which is when I know it's ready to crank. If i start it before then it cranks longer.

 

[buickGN3:16]

its never gonna hold too long. its doing way better than mine, id say your good!

 

[Turbo6Smackdown]

What's the factory standard?

 

[buickGN3:16]

U mean factory psi?

 

[Turbo6Smackdown]

No, the factory standard for how long it should hold for? This shop manual on cd sucks; it doesn't bring up dick in a search, when I know good and dam well it's in there. And the fuel section of the manual doesn't even mention a fuel pressure regulator lol.

 

[Bescurred]

In for the result...mine has done this too and i'm talking about DAYS after lol I could have a ghost

 

[buickGN3:16]

No, the factory standard for how long it should hold for? This shop manual on cd sucks; it doesn't bring up dick in a search, when I know good and dam well it's in there. And the fuel section of the manual doesn't even mention a fuel pressure regulator lol.

. Ok i get what ur sayin but i have no idea about that

 

[Turbo6Smackdown]

Roger.

 

[LEGACY_GN]

There is another thread right now where a guy has low pressure and someone said it should have half the pressure after 30 minutes which is exactly what I'm at. Its supposed to be 43 with vacum hose off the regulator, which is what mine is. 40 with hose on.

Here's the thread. http://www.turbobuick.com/forums/threads/gas-soaked-plugs.410660/

 

[SHADOWII]

Back when my 86 was about 4years old, the fuel pressure would hold to ~27# on the next morning. But I would always let it idle for several minutes before shutting her down. That may have equalized the f/p from pump to rail and reducing any variations in pump speed or across the fuel filter(especially if it was getting close to replacement time.) The mod'd cars seem to fall somewhat faster, but I haven't really paid any attention to it unless I think there is a problem.
Did you actually drive it or just start it and read the gauge? You may have trapped an air bubble in the rail or the back of the gauge from removing and replacing the f/p/r.(?)

 

[Turbo6Smackdown]

I just started it. Never drove it.