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fuel pressure questions

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Old 07-15-2010, 10:47 PM
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ok i just got my autometer fuel pressure gauge in and i finished wiring it up earlier and i noticed that while idleing and cruising pressure stays at 55-58psi, but then WOT it falls to 40psi. I know its not supposed to be that low. I have a walbro intank so i shouldnt be having a pressure problem unless its my filter witch is fairly new but im going to change tommorow anyway. Could it be my regulator?

i need to fix it before sunday so i can get my dyno tune done.

any clues?

right now im going to start with filter, if that dont work, regulator, if that dont work im going to pull the pump and check the line inside the tank.

Thanks,
Caleb
Old 07-15-2010, 11:03 PM
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I have a gauge for that
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Upgrade the wires and change the filter. Thats about all you can do without upgrading the pump.
Old 07-15-2010, 11:09 PM
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Test the electrical connections at the sending unit. They may not be secure and are causing a constant supply problem which is making the voltage drop & reading lower while under load.

Have you contacted support at Autometer? They are very fast in responding & can give you the proper test procedures. I think it's best to go that route before dropping the tank & checking the lines/pump.
Old 07-15-2010, 11:12 PM
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yea i planed on getting a hotwire kit, but upgrade the pump.....shouldnt my walbro 255 support my mods?

im really hoping its the filter cause i dont think ill have time to pull the tank and check the hose before sunday.....i may just drop it off at a friends shop in the mornin for him to take a look. maybe its the regulator??
Old 07-15-2010, 11:15 PM
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Might be the FPR, more then likely its going to be a connection or the line in the tank is shitted up..
Old 07-15-2010, 11:16 PM
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Originally Posted by bai78
Test the electrical connections at the sending unit. They may not be secure and are causing a constant supply problem which is making the voltage drop & reading lower while under load.

Have you contacted support at Autometer? They are very fast in responding & can give you the proper test procedures. I think it's best to go that route before dropping the tank & checking the lines/pump.
its possible....because i have the caspers fuel rail t fitting for one line to fuel noid and then the gauge fitting to sending unit. Maybe its not getting a good read on pressure?

i have a mechanical gauge i can test with i just cant see it while driving if its under the hood
Old 07-15-2010, 11:25 PM
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If the wideband says all is good, I would say it is an electrical/connection issue versus mechanical.
Old 07-15-2010, 11:27 PM
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it is going lean at WOT, i need to calibrate my sensor to check that my wideband is reading right though.
Old 07-17-2010, 11:50 AM
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i changed my filter and took my pump out and replaced the stock feed hose with a high pressure goodyear ruber line with the blue nylon liner or something and i got pressure back.
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