5.3L only running at 45psi
5.3L only running at 45psi I have a 2001 5.3L in my 82 Monte. Fuel pressure is too low. Any thoughts??
Fuel pressure is only reading 45psi. I have checked it with 2 different gages.
I have tried 2 different fuel pressure regulators. (On the rail)
Clamp return line, pressure goes to 80psi.
New Walbro 255lph. Filled 1 gallon in 45sec. Basically 80gal per hr.
Clamped return line then clamped supply line and killed engine. Bled to 60psi. Pressure held constant for 20sec. Did not try longer.
Fuel pressure is only reading 45psi. I have checked it with 2 different gages.
I have tried 2 different fuel pressure regulators. (On the rail)
Clamp return line, pressure goes to 80psi.
New Walbro 255lph. Filled 1 gallon in 45sec. Basically 80gal per hr.
Clamped return line then clamped supply line and killed engine. Bled to 60psi. Pressure held constant for 20sec. Did not try longer.
Restricted User
Joined: Mar 2014
Posts: 7,192
Likes: 109
From: Ohio
Your pressure is about 10 PSI low across the board.
If you can clamp the return and pressure climbs that high, then obviously the problem is the regulator allowing too much flow through the return at too low of fuel pressure.
If you can clamp the return and pressure climbs that high, then obviously the problem is the regulator allowing too much flow through the return at too low of fuel pressure.
I have bought 2 brand new regulators. 3 including the initial.
What about the pump flow. Could it be good with no restrictions but get poor as pressure builds?
Leaking injector when car is running?
What about the pump flow. Could it be good with no restrictions but get poor as pressure builds?
Leaking injector when car is running?
Restricted User
Joined: Mar 2014
Posts: 7,192
Likes: 109
From: Ohio
The regulator controls pressure.
If an injector was leaking bad enough to drop pressure below being regulated, it would have to leak so much fuel that the pump wouldn't be able to produce enough pressure to even open the regulator and send fuel down the return line. That much fuel leaking would be extremely noticeable.
If you can clamp the return line, you are simulating the regulator seizing. If you get 80 PSI doing this, there is nothing wrong with your pump.
If an injector was leaking bad enough to drop pressure below being regulated, it would have to leak so much fuel that the pump wouldn't be able to produce enough pressure to even open the regulator and send fuel down the return line. That much fuel leaking would be extremely noticeable.
If you can clamp the return line, you are simulating the regulator seizing. If you get 80 PSI doing this, there is nothing wrong with your pump.
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I just can't bring myself to spend another $65. That would be the 4th regualtor.
Is there anything else to check?
Car runs well. Slowly increases to 50psi when I get on it.
Is there anything else to check?
Car runs well. Slowly increases to 50psi when I get on it.
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