Fuel Pump pressure drop after warm-up

Guest

I recently modified the Holley Carb on my motor by adding Holley's adjust-a-jet; things went very well and I got the motor running and ajusted the mixture with the vacuum gage and got everything set. I tested the Pantera and felt the additions were well worth the cost and efforts. I got to the GARAGE (as my wife calls it) and noticed that the fuel pressure had dropped to 1lbs; I had it set@ 5lbs on the regulator, when I went to adjust the regulator I no responce. Later after the motor had cooled off I started the motor and the fuel pressure was at 7lbs. I thought the the pump was going bad so I replaced it with an Electrical type from Holley and replaced the fuel filter as well; I thought that these changes were the FIX...... Same problem....... Need some insight from all of you on the issue..... John

5/16/018:03 AM

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mikep01 (Guest)

try another fuel psi guage. the gauge should be in line betwen the carb and the pump.

5/16/016:15 PM

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bosswrenchMember

I've seen this happen when the fuel pressure regulator is the toy chrome unit sold thru discount auto parts stores, that has a rotating center to set pressure. Problem is, these things won't flow enough fuel to keep a 4bbl float bowl full regardless of the setting. They were designed for VWs and are barely adequate for 2 1-bbls on a 1600 cc engine. Don't worry about your fuel pressure- take the regulator off and try a full throttle run without it. On a Weber-equipped 289 Cobra. s-canning the toy regulator and running naked, the fuel pump could barely keep 4 lbs in the float bowls and the rig worked just fine both street & rtrack.

5/16/0111:38 PM

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