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Old 06-08-2009, 01:34 AM   #1
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Default Fuel pump pressure

So ive been wondering why my 460cc injectors are maxing out at 5lbs. First i checked and verified that my practically new fuel filter is not on backwards. Next i bought a fuel injection pressure kit. I attached it to the line that goes towards the fire wall which i am almost positive that this is the feed line. Turned the car on and went at looked at the gauge while running and it read 0 psi.

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Next i opened up the fuel tank lid inside the cab and switched the lines to see if i was feeding through the return line. I was not as the car would not start.



Just now i finally got off my lazy sunday *** and went at tested the pressure Directly above the fuel pump and turned the key to the on position and guess what.. only 15 psi for a walboro 190 FP

Is this what its suppose to be?
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Old 06-08-2009, 01:42 AM   #2
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No, it's much too low. Your FPR might be bad. Try pinching the return fuel line to see if the pressure goes up.

--Ferdi
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Old 06-08-2009, 01:49 AM   #3
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From what ive heard pressure on stock fuel pump is around 40 psi @ idle.

Heres the 2 pressure i just took for some eyes

Key in ON position
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Cranking

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Could my fuel pump be bad? or not connected correctly?
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Old 06-08-2009, 02:09 AM   #4
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1. Read the replies to your thread. Someone already told you this.
2. Pinch your return line to see if your FPR failed. I've had an OEM FPR fail.
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Old 06-08-2009, 02:15 AM   #5
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Should i reconnect the fuel pressure gauge to where it was in the first pic or will it work where it is in the last picture
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Old 06-08-2009, 02:22 AM   #6
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In that last pic, is the gauge just connected to the fuel pump output? No tee? Then something is definitely off with the pump.

1. Check the voltage at the pump.
2. Maybe the little hose between the pump and the bulkhead fitting is leaking.

--Ferdi
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Old 06-08-2009, 02:31 AM   #7
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Thanks for the input. Its a little to late to be workin on the car right now. Ill have hit it again tomorrow.

Any idea what the voltage is suppose to be?

Im pretty sure its not leaking although i will double check that
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Old 06-08-2009, 02:40 AM   #8
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The voltage should be whatever the battery voltage is. ~12V with the car off and ~14V with the car on.

With the gauge hooked up directly to the pump's output, the pressure would probably be close to 100psi (my guess with the pump being dead headed).

--Ferdi
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Old 06-08-2009, 10:46 AM   #9
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Quote:
Originally Posted by Savington View Post
2. Pinch your return line to see if your FPR failed. I've had an OEM FPR fail.
He's measuring directly at the pump. No return line to pinch.

Quote:
Originally Posted by sbkcocker499 View Post
Should i reconnect the fuel pressure gauge to where it was in the first pic or will it work where it is in the last picture
Yes, but make sure you are in fact on the supply side of the rail (the line which goes to the *front* of the rail) and not the return side (the line going to the back of the rail). That's the ideal spot for a measurement.

That said, however, something is clearly wrong with your fuel pump. With the pressure gauge connected directly to the output, you should be seeing 100 PSI, not 10. Could be the pump itself, could be a leaky union between the pump and the rail inside the tank, could be an electrical problem.

Ideally, you want to measure the voltage across the pump itself (one probe from the meter on each of the two wires at the pump) rather than from the pump to ground. Reason is that this will account for any problems in the pump's ground as well.

As ftjandra said, voltage should be within a few tenths of battery voltage.
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Old 06-11-2009, 11:26 PM   #10
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So this evening i got my fuel pump out of the tank and saw this
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The o ring was visible which was causing a leak

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Fuxerd up

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even fucked up without the flash

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Used some fuel line and stuck the tit of the FP in it and then jammed it in the hole and was real snug (which i like ) Finished with a little clamp and eureka

65 psi with a leak on the gauge and the fuel cap open

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Decided to rip out my old IC setup

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Heres whats goin in

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Thanks for the help guys
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