Erratic Fuel pressure - Team Camaro Tech
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post #1 of 7 (permalink) Old Oct 10th, 03, 08:22 AM Thread Starter
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Greg
 
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I am running a holley mechanical 130gph fuel pump. It says that it does not require a regulator. When the car is idling the fuel pressure guage fluctuates very rapidly between 4-7 psi. The needle moves back and forth very quickly. Does anyone know what could be causing this? The car seems to idle fine although I do have a slight miss that I am trying to figure out.

68 Island Teal
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Hotchkis TVS with Global West UCA's


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post #2 of 7 (permalink) Old Oct 11th, 03, 06:09 PM
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If it is actually the preasure fluctuating it might be an air leak on the intake side of the pump. I'd imagine a leak on the output would of already been spotted. Some place along the line a switcharo has happened with the fuel and return line of the tank and from what I've heard the car will still run but runs bad with that set up. What I'd suspect is actually going on is the pump is reading every squirt of a diaphram pump. Is it electric or a cam driven pump?
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post #3 of 7 (permalink) Old Oct 12th, 03, 08:44 AM
 
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The fuel pressure gauge is it a fluid filled unit (more expensive type). I installed a non fluid filled fuel pressure gauge at the same time I upgraded to a electric fuel pump and new fuel line. The gauge would bounce around wildly from 3 to 9 psi. I knew the fuel pressure was non changing (fuel pressure regulator), So replaced with a fluid filled unit now it stays steady at 7-psi.
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post #4 of 7 (permalink) Old Oct 13th, 03, 06:02 AM Thread Starter
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Greg
 
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Its not a fluid filled one. Its a cheapo one that came with the fuel line in a kit. I'll upgrade the gauge to rule that out.
Thanks,
Greg

68 Island Teal
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post #5 of 7 (permalink) Old Oct 13th, 03, 12:23 PM
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Hey GregD

I had the same problem with a cheap gage. It drove me crazy. I changed the reg same problem. I installed a BG gage cleared everything up.
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post #6 of 7 (permalink) Old Oct 14th, 03, 05:47 AM
a67
 
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You can place a snubber in the gauge port. Just need something with a tiny hole (30 thou) in it to dampen the pulsing.

The better gauges have a piece that threads into the port on the gauge itself. Problem is that sometimes they fall out. I've had them jam the regulator open.

Bob.
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post #7 of 7 (permalink) Old Oct 21st, 03, 02:37 AM Thread Starter
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Greg
 
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Angry

I ended up getting a liquid filled gauge and it solved the problem. Thanks guys!!

68 Island Teal
383/700r4
Hotchkis TVS with Global West UCA's


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