Quote:
Originally Posted by Boosted Performance
So I have been looking at my fuel pressure as well...
Full blown fuel return kit, with a fuel pressure regulator, and pressure gauge. No vacuum line connected to the regulator from the manifold. The car is still stock other than the fuel return kit, which also has a 14 ga wire from the batter all the way to the fuel pump.
I had set the fuel pressure at 51psi, as per FSM, with the engine all warmed up. I did notice that the fuel pressure will go up as high as 56psi when the engine is cold, and it does take 10-15 minutes of driving for it to come back down to what I set it to. This is about a 9% fluctuation.
I also noticed that the OEM volt gauge will go from about 14.4, to below 13.6...ish cold vs warm, which is about 6%.
I think it is safe to notch the last 3% of fluctuation on the heat, and the influence it has on the spring in the FPR.
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That’s strange ...mine is the opposite ...it’s dropping pressure from set point ....I had it set around 50 without vacuum line on it ...with vacuum line it dropped to around 45 ....after twenty mins of driving it would drop to 38 ish ...I watched it while idling and it would start to bounce from 35-38 .....sooooo i lowered the pressure down to 28 then increased it to 65 just to see if the regulator was hanging up ....I set it back to 52 without the vacuum it dropped to 50 with vacuum line on ....took it out for a drive for awhile got back home and checked it ..still holding 50 .....I’m wondering if there is a issue with the regulator that is magnified at lower pressure , now I’m just guessing ...there are really only a few things that can affect pressure ...vacuum source ..regulator ...pump ...voltage.....I’m using the vacuum lines off the throttle body for regulator source ..I’m gonna ty to switch it to another one to see if there is a change