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In my quest to figure out why my '70 L46 is flooding during initial start (after having the correct Q-jet recently rebuilt by Lars), Lars suggested the next step would be to check my fuel pressure. He just got done checking the carb out for me a second time to confirm no trash in the needle seat, float operating properly, etc...
In previous posts, I have seen suggestions to install a "T" fitting between the end of the fuel line and the carb to allow hookup of a pressure gauge. Has anyone done this or similar before? If so, could you post photos or refer me to where to find such a fitting for this application?
As far as I know, my fuel pump is original - at least I can't find any aftermarket wording or logos on it (photos below). I did replace the fuel line from the pump to the carb, but that is all I've done to the fuel system.
My carb is in the mail coming back to me right now from Lars. Maybe once I get it re-installed everything will be fine, but I'm trying to prepare in case I have a problem somewhere else.
Here’s the configuration of the fuel pump pressure tester that I made by using a section of an old fuel pump to carburetor steel line that I cut and purchased a tee and pressure gauge from Summit. The steel tubing end threads into the carburetor and the open ended hose will slip over the end of the fuel line from the fuel pump at the carburetor end. This will allow the motor to run so you can observe the pressure.
Also your fuel pump is not a AC #40769 fuel pump which would be original to 1970 L46. The fuel pump in the pic that I posted shows the bottom of a AC service replacement pump which looks the same as an original.
Last edited by boat196; Feb 24, 2023 at 06:22 PM.
Reason: Add pics remove number
From: At my Bar drinking and wrenching in Lafayette Colorado
Ron -
Rather than posting here on the Forum, why don't you just e-mail me and ask me this question so I can send you the info on how to test fuel pressure?
Ron -
Rather than posting here on the Forum, why don't you just e-mail me and ask me this question so I can send you the info on how to test fuel pressure?
Lars
Sorry Lars, I thought maybe you'd be sick of hearing from me by now! Plus, I figured you never know who else out there this might benefit...
I am sure there are better ways..but i used vacuum fuel gauge and measured pressure. The other critcal measurement is flow. Mine passed pressure and failed flow..
my Lars carb runs perfect even at highest end of pressure range ..
also check your fuel lines here if you have an hour to read…maybe plugged return line if you have one?
also fuel pumps are VERY hard to find good ones..i went through a few.. https://www.corvetteforum.com/forums...e-on-road.html
Last edited by interpon; Feb 25, 2023 at 09:53 AM.
Testing fuel pressure
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