FUEL PSI FLUCTUATING

Old 09-29-2009, 02:14 AM
  #1  
JEFF69Z28
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Default FUEL PSI FLUCTUATING

WHAT WOULD CAUSE MY FUEL PSI TO CHANGE?I SET IT AT 7.5 ONE DAY THE NEXT TIME I RUN IT ITS 6 OR 8,MONDAY WHEN I STARTED THE CAR IT WAS 12.I USE A HOLLEY BLUE PUMP,AEROMOTIVE PSI REGULATOR AND A AEROMOTIVE FUEL FILTER (10 MICRONS).A BRAIDED FUEL LINE AND A AUTOMETER LIQUID FILLED FUEL PSI GAUGE.
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Old 09-29-2009, 04:49 AM
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mytmouz
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The liquid filled gauge is usually the cause. Drain it and see if it stays put before you do anything else...
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Old 09-29-2009, 07:00 AM
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JEFF69Z28
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Originally Posted by mytmouz
The liquid filled gauge is usually the cause. Drain it and see if it stays put before you do anything else...
HOW DO I DRAIN IT?
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Old 09-29-2009, 07:27 AM
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OneBadGMC
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Man I wouldn't drain that, lol...

Did you orient the fuel pressure gauge to where the vent plug in back is at the top? Is the plug loose? Liquid filled gauges have to be vented, or as atmospheric pressures change, the gauge will be thrown off by expansion/contraction of the oil in them.
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Old 09-29-2009, 07:44 AM
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JEFF69Z28
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AS I SIT AT MY DESK I WAS REMEBERING THE LAST TIME I RACED,WHEN I STARTED THE CAR PSI WAS AT 6 I DIDNT ADJUST BECAUSE THE DAY BEFORE I SET IT AT 7.5.WHEN I MADE A PASS IT WAS ACTING FUNNY LIKE IT WAS STARVING FOR FUEL.I ADJUSTED IT TO 8 PSI AND IT RAN FINE,IM THINKING THE PSI REGULATOR COULD BE BAD OR MAYBE SOMETHING STUCK IN IT.
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Old 10-02-2009, 09:58 AM
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rob41willys
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I would look at the regulator.
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Old 10-03-2009, 10:21 AM
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Check the guage. I use 2, one on the regulator and 1 on my cowl.( attached in-line at the reg.) They never read the same. One on the dash always shows 6.5, the reg (new BG) always shows 7.5.
Every now and then the one mounted outside gets hung up at 3 or 4psi.
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