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Discussion Starter · #1 ·
I have a fuel issue, when I start my motor up I get 4.5 PSI of pressure, once the engine comes up to operating temperature my fuel pressure starts going down to 2 PSI, I have my 3/8 Steel fuel line rapped in Heater hose rubber to eliminate the heat, I have a feeling it’s my Mechanical Fuel pump, I currently have a Summit Racing Mechanical 110GPH #SUM-250022-1, its says max pressure 8 PSI I’m only getting half of that pressure, I’m thinking of using an Edelbrock #1722 110GPH, do you think this will be enough to feed my BB 427?
I also have installed a howards Blended Carbon Polymer push rod
 
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Discussion Starter · #5 ·
when I first got the engine in and was tuning her up my temperature was getting over 200*F and the pressure went down to 0 and the car shut down
 
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#7 ·
When you first fire the car up, did have a 8 psi pump, I take you had a fuel regulator on it, or you would probably blow the needles open in the carb.
If you have 4.5, and 2 lbs and the gauge is reputable ( i would still try another), and you have no fuel problems from the tank, such as a 90 deg fitting on the pump suction, then by all means change the pump.
I actually, on the one with a bad gauge, went from an Edlebrock to a Summit and the Summit did better. At that time Summit was re-boxing Holley products under their name.
Hope you get it, I just now always double check gauges.
Never used that fuel pump rod, personally I would check it if you pull the pump if you have not used it before.
Depending on the engine mods, 110 gph I think would be fine.
Good luck, hope it is something simple.
 
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Discussion Starter · #8 ·
Bluegoose1970 said:
When you first fire the car up, did have a 8 psi pump, I take you had a fuel regulator on it, or you would probably blow the needles open in the carb.
If you have 4.5, and 2 lbs and the gauge is reputable ( i would still try another), and you have no fuel problems from the tank, such as a 90 deg fitting on the pump suction, then by all means change the pump.
I actually, on the one with a bad gauge, went from an Edlebrock to a Summit and the Summit did better. At that time Summit was re-boxing Holley products under their name.
Hope you get it, I just now always double check gauges.
Never used that fuel pump rod, personally I would check it if you pull the pump if you have not used it before.
Depending on the engine mods, 110 gph I think would be fine.
Good luck, hope it is something simple.
Click to expand...

When I first start the car I'm only getting 4 PSI, I never had 8 PSI, I don't have a fuel regulator installed, I know the gauge works because when the pressure went down to 0 PSI the car shut down, the only thing about the line running from the tank to pump is there's a small kink where the line comes out the frame

I just have a feeling its the pump its says right on it "Made in Korea"

The engine is a 427 bored .60 over, Edelbrock aluminum heads, luanti hyd roller cam, somewhere around 500HP,




 
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#9 ·
Nice engine.
Everything looks good, the gauge going to zero really does not mean it is good especially if it has a zero stop post in it.
If you have a vacuum gauge that also does fuel pressure, disconnect the line and hook it up direct, crank it, you do not have to buy a gauge, and it is something you should have for tuning.
Check the fuel pump rod length, might be short.
Then I would change pump, bigger pump isn't going to hurt, just more spring tension on fuel rod and cam.
Any pump 8 psi or higher, get a regulator. I had a 8 psi pump ( did not know it, came on car) and it would open the float needles.


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Discussion Starter · #12 ·
Stokerboats said:
Pull out the sender at the tank and check the sock or for obstructions in the fuel line up to the carb. It's a fairly easy check before you spend any money. Good luck.
Click to expand...
I have already changed the sender unit with a brand new spectra premium unit
 
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#13 ·
Have you tried another gauge by chance?


Been fighting a similar issue sbc carter 172
Thought i had some dirt in the needle/seat would want to slowly idle down and almost die or just die if in constant low speed traffic or idling a lot

Long story short when the coolant hit 185/190 the fuel would start percolating couldnt figure why the float was going up. musta cleaned it out half dozen times.

Of course once shut off youd see a little gas going down the primaries
Yeah needle and seat/oring right? Just gas getting too hot

Fuel lines a little too close to the lower hose I think.
If the car isnt stuck at a constant standstill its fine.
Dont know if this helps.
 
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