Erratic fuel pressure reading?? - Team Camaro Tech
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post #1 of 6 (permalink) Old Aug 18th, 03, 09:44 AM Thread Starter
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Join Date: Aug 2002
Posts: 133

Hello again,

My 502 is running great, however I'm getting an erratic fuel pressure reading through the gage. I have # 8 line from the fuel cell to the filter # 8 line from the filter to the pump ( summit 140 gph electric pump ) from the pump to a Barry Grant 2 port Regulator from the Reg to the carb. On the carb line which is # 8 I have a Summit liquid filled fuel gage. During start up the gage reads 9 to 14 psi. I'll set it back between 6 and 7psi it stays. After driving the gage will read 3 psi until I reset it to 6-7psi. Any thoughts as to why the gage is fluctuating? Could it be a faulty gage? faulty pump? Should I go with a dampened BG gage? This is driving me crazy. Thanks , Joe

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post #2 of 6 (permalink) Old Aug 18th, 03, 03:08 PM
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Location: Carlisle, PA
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I had a similar problem on my camaro. My pressure would be fine when I first turn the pump on. After a little while, my pressure would drop and the motor would starve for fuel. Turned out to be a bad fuel pump. How does your fuel pump sound? It is supposed to have a very steady tone to it, which mine didn't. You could hear the tone of the pump motor changing every couple seconds. I got another pump and everything is fine now. [img]graemlins/thumbsup.gif[/img]
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post #3 of 6 (permalink) Old Aug 19th, 03, 12:54 AM
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Joe, your situation looks exactly like what I encountered a few weeks ago. Istalled a new Holley pressure regulator, together with a liquid filled gauge. You know, trying to have the best gauge. Seems those liquid filled "mo%&**$#rs" have the tendency to reduce their indication when warm. Try this, when the car gets warm, lift the rubber vent from the gauge with your nail, but just enough to let some air in/out?. Looks like the fluid (glicerin?)gets hot and expand/contracts or something and affects the reading. Try to do this with the vent up wards, so you don't loose liquid. You should be able to see the needle go up again. Maybe some kind of pressure differential, inside the gauge vs. ambient? [img]graemlins/clonk.gif[/img] It worked for me. Try it and let us know, maybe the non liquid lilled gauge is a better option for more accurate readings.
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post #4 of 6 (permalink) Old Aug 19th, 03, 02:22 AM Thread Starter
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Thanks everyone,

I'm going to try both sujestions. I also ordered a new gage ( non liquid filled BG gage). I noticed if you touch the face of the gage when the car is running the reading will move all over the place. I should have the new gage tomorrow night I'll will let you know how it goes. Thanks again!!
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post #5 of 6 (permalink) Old Aug 19th, 03, 03:55 AM
Join Date: Apr 2003
Location: n.j.
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joe i think you have to drive up and down main street of somerville 80 times on a friday. then the gauge will start working [img]graemlins/waving.gif[/img] definetly start with the easy things first like gauge and regulator hopefully that will get you cruzing again!! see ya soon wheelzy...........

wheelzy 67
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post #6 of 6 (permalink) Old Aug 19th, 03, 04:30 PM Thread Starter
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Hey wheelzy! [img]graemlins/waving.gif[/img]

Cruzin Colorado Cafe Thursday night come on down. Will be in Somerville on the 29th. As far as the gage I drained the liquid out and it seemed to work ok. Tomorrow I should have the BG gage. I'll let ya know how it goes.

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