Forces Posted May 24, 2007 Share Posted May 24, 2007 5.0 using Holley fuel pump, pressure regualtor w/ dual out let. One outlet is going to the carb (heeee-yuk) and the other is going to an oil filled gauge. It feeds into an Edelbrock Performer 650 cfm auto-choke carb. At idle the fuel pressure surges between approx. 3 psi and 7 psi. But it doesn't do it right away. I'll fire up the engine, and the pressure is stable at about 5 psi. Then after about 30 seconds, maybe less the fuel pressure goes tits up. I bench tested the regualtor using a compressor, and the gauge seems to be reading accurately. I am thinking that the delayed reaction with the pressure fluctuation is related to the fuel bowls filling back up after the engine uses the fuel that was in them before starting it. The floats are set to Edelbrock spec 7/16". The metering rods and step ups are stock per edelbrock. Really bizarre, any ides? Quote Link to comment Share on other sites More sharing options...
Spraguepsycho1 Posted June 6, 2007 Share Posted June 6, 2007 Is there any way you can connect a guage in the line that you are running to the carb, or plug the line to the carb for a few seconds then start it and see if the pressure still surges when the fuel isn't able to flow? Maybe it's just showing a surge on the line with the guage because the other line is flowing and holding constant pressure? Since you're naturally aspirated I wouldn't worry too much about the pressure as long as it stays where it is now, the flow volume is more important and being a Holly pump, flow most likely isn't an issue. Is the engine surging at idle or holding steady? Is it starving for fuel at full throttle or high rpm? Is the pump new or something that you've been using for many years, with the pressure surge being a new problem? Quote Link to comment Share on other sites More sharing options...
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