Fluctuating Fuel Pressure
04-06-2005, 09:56 PM
#1
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this is from the q and a section of aeromotive's site
5.) My regulator doesn't seem to keep consistent pressure, every time I look at the gauge it reads something different, what is going on?
Chances are good you have a liquid filled fuel pressure gauge. This type of gauge will change it’s reading as the temperature of the gauge case changes. Because it’s sealed to contain the liquid inside, a liquid filled gauge no longer compares fuel line pressure to actual atmospheric pressure, reporting the difference. Instead, it compares fuel line pressure to the pressure inside the gauge case. Unfortunately, as the liquid in the case heats or cools, it expands and contracts, causing case pressure to change as much as 7-12 psi plus or minus. As a result, gauge readings can fluctuate from 40 psi cold to as little as 28 psi hot! Fuel line pressure is NOT actually changing, just the pressure in the gauge case. To confirm if this is occurring, procure a heat gun or blow dryer and heat the gauge from cold to warm and then hot, while running the fuel pump. Observe if the pressure reading drops, if so, you found the problem.
has anyone else experienced this other than just me?
5.) My regulator doesn't seem to keep consistent pressure, every time I look at the gauge it reads something different, what is going on?
Chances are good you have a liquid filled fuel pressure gauge. This type of gauge will change it’s reading as the temperature of the gauge case changes. Because it’s sealed to contain the liquid inside, a liquid filled gauge no longer compares fuel line pressure to actual atmospheric pressure, reporting the difference. Instead, it compares fuel line pressure to the pressure inside the gauge case. Unfortunately, as the liquid in the case heats or cools, it expands and contracts, causing case pressure to change as much as 7-12 psi plus or minus. As a result, gauge readings can fluctuate from 40 psi cold to as little as 28 psi hot! Fuel line pressure is NOT actually changing, just the pressure in the gauge case. To confirm if this is occurring, procure a heat gun or blow dryer and heat the gauge from cold to warm and then hot, while running the fuel pump. Observe if the pressure reading drops, if so, you found the problem.
has anyone else experienced this other than just me?
04-07-2005, 09:40 AM
#6
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ok i think my fluctuation is caused by my fuel filter or some other obstruction in the fuel line. i screwed the adjuster all the way down with no change in fuel pressure, then raised the adjuster up and lost fuel pressure.
04-07-2005, 04:47 PM
#7
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[quote name='FikseRxSeven' date='Apr 7 2005, 09:40 AM']ok i think my fluctuation is caused by my fuel filter or some other obstruction in the fuel line. i screwed the adjuster all the way down with no change in fuel pressure, then raised the adjuster up and lost fuel pressure.
[/quote]
definatly would replace the filter, but you should be able to "dead head" the pump and the pressure shoot up. If not, i'd be looking for a new pump too.
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definatly would replace the filter, but you should be able to "dead head" the pump and the pressure shoot up. If not, i'd be looking for a new pump too.
04-07-2005, 06:52 PM
#8
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[quote name='mazdadrifter' date='Apr 7 2005, 04:46 PM']definatly would replace the filter, but you should be able to "dead head" the pump and the pressure shoot up. If not, i'd be looking for a new pump too.
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what does dead head mean?
i hope its not the pumps, they're 2 walbro 255s thats only about 2k miles old.
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what does dead head mean?
i hope its not the pumps, they're 2 walbro 255s thats only about 2k miles old.
04-14-2005, 09:22 PM
#10
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has there been any history of people clogging pumps and filters with premix?
i added a new tank of gas, and added the premix and drove about 20 miles... by the time i got home, the car was sputtering the 1st split second after switching gears, and when i checked the fuel pressure, it was down to 25lbs
i added a new tank of gas, and added the premix and drove about 20 miles... by the time i got home, the car was sputtering the 1st split second after switching gears, and when i checked the fuel pressure, it was down to 25lbs