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Fuel Pressure Reading

842 Views 5 Replies 4 Participants Last post by  gearheadhick429
Ok replumbed the fuel line from to pump to carb. Also added a fuel pressure gauge to see what kind of reading I would get on cold start up it read 5psi, after it was good and warmed up pressure slowly dropped to 1 psi.


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Hello. :) 5psi is about right, but, obviously, 1 is too low. But, if the car can keep running at higher RPMs when it's warmed up, I would suspect that the gauge is not telling me the truth. I have heard that those gauges from Summit read a little low when they get warmed up, but, I do not know this to be a fact. I think that I would call the Summit tech people and see what they had to say about this. :)
if i had to guess, and considering the gauge is correct, i would say that your having some sort of a vapor lock issue. run the engine with the gas cap off and see if this happens again. if it keeps happening, you can always verify the gauge by carefully removing a fuel line and running it into a large bottle and starting the car. if fuel flows well, id say the gauge is wacked.

if you really have 1 psi, you should be seeing issues at 65mph.
What I noticed when I had a clear glass fuel filter on the line was after it really warmed up the filter emptied out it went from being almost full to nothing but small amounts of fuel sputtering thru.
Make sure your fuel lines are fastened up and away from the exhaust. Good Luck.
if it went from full to empty all in the process of one run, then it has to be vapor lock. remove the gas cap and drive it. if this fixes it, your fuel system is not breathing properly.
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