Topic: Fuel Pump
in Forum: C3 Fuel, Emission Control, and Exhaust Systems
Already a Member?
Click Here to Login
Not yet a Member?
Click Here to Register for Free!
SPONSOR AD:: (Our Sponsors help support C3VR)
Former Member
Send PM
Mounds View, MN - USA
Joined: 5/24/2007
Posts: 1031
Vette(s): 70 LT1 coupe, 69 350 HP coupe, 69 390HP 427 coupe, 71 LS5 convert, 85 coupe, 93 coupe
I would wrap a rag around an air hose to make sort of a seal to the fuel filler, and blow into the tank. If you see fuel leaking somewhere, that is the problem. If you hear air, but do not move fuel, find the leak. There is an old troubleshooting rule that says to recheck whatever you changed most recently. Maybe your sender/pickup has sprung a leak. There are two vastly different quality level units on the market.
Larry
Larry
Lifetime MemberManteca, CA - USA
Joined: 11/20/2005
Posts: 3623
Vette(s): 1978,two tone,Metalic Rootbeer & gold
1975 L48 4 speed
Dave and I got together on Sunday to check this out and I have to say, it's the strangest thing I have ever seen. He put 5 gals. fuel in the tank but no fuel gets to the carb, and with all the hoses intact, we changed out the pump. Still not picking up fuel, we disconnected the fuel line from the pump and blew compressed air back up the fuel line to the tank to ensure that the pickup end of the fuel line was indeed immersed in fuel. We heard air coming out but no bubbling sound 
. Now, we used a dip stick into the tank to guarantee we still had fuel and there was at least 6 inches deep, so you have to wonder, could it be possible for the bladder to deform in such a way as to dam up more than 5 gals. of fuel away from the pickup tube. Dave just pulled the tank and replaced the fuel pickup assembly last month. We're now looking at replacing the fuel tank because there seems no other recourse. What do ya think guys?
. Now, we used a dip stick into the tank to guarantee we still had fuel and there was at least 6 inches deep, so you have to wonder, could it be possible for the bladder to deform in such a way as to dam up more than 5 gals. of fuel away from the pickup tube. Dave just pulled the tank and replaced the fuel pickup assembly last month. We're now looking at replacing the fuel tank because there seems no other recourse. What do ya think guys? Jimmy B.
Just can't wait to get on the road again. 
Click to see larger views!
Lifetime MemberModerator
Duncanville, TX - USA
Joined: 11/8/2003
Posts: 20214
Vette(s): #1-1974 L-48 4spd Cp Med Red Metallic/Black deluxe int w/AC/tilt/tele./p/w-p/b/
Am-Fm/map light National/Regional/Chapter NCRS "Top Flight"
#2-1985 Bright Red/Carmine Cp.L-98/auto
Member: NCRS, NCRS Texas, Corvette Legends of Texas
There was no mention of there being any bladder distortion when the sender was changed, so I didn't think that would be an issue. It could very well be the problem....put some more fuel in it and see....
Joel Adams
C3VR Lifetime Member #56 
My Link 
(click for Texas-sized view!) NCRS
"Money can't buy happiness -- but somehow it's more comforting to cry in a CORVETTE than in a Kia"
Ok hookup a fuel can to the pump and it started working. So I reconnected the lines and it ran for 1 min then stop. It must be the tank or the rubber fuel hoses the tank. I guess I will redrop the tank and take a closer look at everything and hope I fine something?
Questions? Drop the fuel tank and did not see anything unusual in the tank. Put a fuel can up the fuel line and the car started. So the fuel pump and the fuel line leading up to tank are good. The fuel sender is new. Now what? Is there a test for the fuel sender? The only thing that gives me pause is the bend on strainer tube on the sender.
Lifetime MemberModerator
Duncanville, TX - USA
Joined: 11/8/2003
Posts: 20214
Vette(s): #1-1974 L-48 4spd Cp Med Red Metallic/Black deluxe int w/AC/tilt/tele./p/w-p/b/
Am-Fm/map light National/Regional/Chapter NCRS "Top Flight"
#2-1985 Bright Red/Carmine Cp.L-98/auto
Member: NCRS, NCRS Texas, Corvette Legends of Texas
Can you blow thru the sender and verify it is open/clean?
Joel Adams
C3VR Lifetime Member #56
My Link
(click for Texas-sized view!) NCRS
"Money can't buy happiness -- but somehow it's more comforting to cry in a CORVETTE than in a Kia"
Yes I can blow in the tube and it is not clogged. Each time that I drop the fuel tank I took out about 10 gallons of gas. Could the angle of the stainer tube have anything to do with it? I am about to give the car to the vette mechanic to let him figure it out
Lifetime MemberLanoka Harbor, NJ - USA
Joined: 12/21/2006
Posts: 828
Vette(s): 1975 metallic blue coupe with t-tops,L48, t/t steering, black leather interior. 1990 L98, white/red leather interior, auto,a/c
i may be wrong but there should be a rubber hose that goes from the tank to the metal fuel line that runs to the front of the car. is it possible that the rubber hose had come apart inside and on suction has a flap that blocks the flow. blowing into the tank wouldn't show this. maybe try disconnecting that hose from the tank a blow through it that way. just an idea
LIFETIME MEMBER #97
THE DYNAMIC DUO
THE DYNAMIC DUO
Yessss, I think I have the problem with the fuel. I thought the sender unit pick up tube look wrong. Talk with Aceinthehole he suggested that I take a wire bend it the same as the fuel sender to see how it looks in the tank. Well the sender pickup tube bend at a 285 degree angle which put the strainer end sticking up out of the fuel. Which would explain why each time I drop the tank I got 10 gallons of fuel out. When the tank was half fuel the sender tube was sticking up past the half point. Lets see what happens when I put the tank back in.
in Forum: C3 Fuel, Emission Control, and Exhaust Systems
SPONSOR AD: (Our Sponsors help support C3VR)