My BROTHER-IN-LAW called with a complaint, his 1974 big block corvette stopped running.
READ THESE RELATED THREADS AND LINKS
READ THIS
http://autolabscopediagnostics.com/fuelpump.htm
http://www.corvettefaq.com/c3/sending/sending.html
http://www.mamotorworks.com/corvette/su ... el-tanks-1
http://www.corvettemagazine.com/tech-ar ... placement/
viewtopic.php?f=55&t=211
viewtopic.php?f=55&t=1939
viewtopic.php?f=55&t=635
viewtopic.php?f=55&t=58
viewtopic.php?f=55&t=6105&p=18854&hilit=fuel+filters#p18854
http://garage.grumpysperformance.com/index.php?threads/c3-corvette-not-getting-fuel-to-carb.11668/
viewtopic.php?f=80&t=8505&p=32546&hilit=1974+corvette+tank#p32546
viewtopic.php?f=55&t=7787&p=28271&hilit=flex+fuel+line#p28271
viewtopic.php?f=55&t=4381&p=16285&hilit=flex+fuel+line#p16285
BTW I WONDER IF VERY MANY GUYS BOTHER TO READ INSTRUCTIONS
http://www.jegs.com/i/JEGS-Performance- ... 2/10002/-1
heres a fuel filter I see some guy installed on his 750 holley carb equipped car and he wonders why he runs out of fuel in third gear,think about it, hes got a fuel filter rated at 130 gallons per hour , certainly adequate...until you realize hes using a manual fuel pump that produces maybe 9psi and the filter flow rates rated at 75 psi, , more than 8.3 times the pressure, so hes likely getting 1/6-1/8th the flow at 9 psi
I came over to help diagnose the problem,so we started on a step by step isolate and verify approach to the problem.
(1) the first indication was the car had good ignition spark and spun over with the started but the carburetor didn,t seem to be getting fuel fed from the fuel tank,
(2) so we confirmed the fuel tank was more than 1/2 -to-3/4 full by looking into the rear fuel fill access door in the rear deck, with a flash light.
(3) removing the fuel line from the carburetor and cranking the engine on the starter, while we had a 6 ft section of 3/8" clear vinyl tubing and a hose clamp to extend the fuel line into a 2 litter bottle so we would not spill and fuel showed we were getting zero fuel pressure at the carburetor inlet.
(4) so we know its got fuel in the tank but its not reaching the engine, so we know either the pumps not working or the feed to the fuel pumps blocked.
(5) The next step I took is disconnecting the fuel feed line into the fuel pump inlet port (which resulted in fuel draining out slowly but I was not sure the line was clear, and I hooked a temporary section of 3/8" vinyl fuel line to the fuel feed line going back to the tank and used my air compressor to pressurize the fuel feed line from the tank,for testing which resulted in a mass of bubbles bubbling up in the tank, and obviously indicating the fuel feed line was fairly clear and the fuel strainer sock in the tank was not seriously blocked. removing the air pressure resulted in in a very slight increase in fuel drain rates, probably resulting from the fuel sock in the fuel tank being slightly less clogged from the recent surge of air pressure flowing thru in the reverse of normal fuel flow direction.
looking into the tank with a strong LED light showed years of accumulated crud so we decided to order a new tank and fuel gauge sensor assembly.
(6) now this is a fair indication the fuel lines fairly free so the next step was to use an adapter fitting in the fuel pumps inlet port with a 6 ft section of 3/8" clear vinyl tubing and a hose clamp to extend the fuel line into a 2 liter bottle we filled 3/4 with fuel to test if the fuel pump would suck and pressurize fuel, as expected the fuel pump proved to be defective as it would not move the fuel.
(7) so the choice at this point is to replace the existing manual pump
or replace the manual fuel pump with an electric fuel pump.
HAVING SOME BRASS, FUEL LINE TEST FITTINGS TO USE WITH THE CLEAR VINYL TUBE, IT HELPS WHEN TESTING BUT SWAP TO REAL FUEL LINE ONCE YOUR ACTUALLY INSTALLING A FUEL SYSTEM
keep in mind this corvette is not going to be used for anything but cruising , so he has zero interest in anything but a nice looking corvette that runs smoothly, and has good passing power on the high way, he has zero interest in racing, our concern here is simply getting the car to run correctly , in stages as he can aquire the required components and allow the cars engine too make decent power in the 1200rpm-5000rpm power band, he has several issues but we will be replacing the ENTIRE fuel system, tank, lines, fuel pump,regulator, intake and carburetor..
ONCE we got all the lines, fuel pump and fuel pressure regulator installed my brother-in-law wanted to take the car for a test drive....it ran like crap , because of several reasons, the main one is a rusty old fuel tank full of loose crud , that will soon be replaced (ITS ON ORDER) so we installed the fuel pressure gauge on the line running between the regulator and the carb and found we had 9 psi of fuel pressure, adjusting the fuel pressure to a much more reasonable 5 psi made a HUGE improvement in the cars power.[/size][/b]
BTW, while it doesn,t apply here in this particular case, one factor I see guys ignore at times is when a in tank fuel pump goes bad, guys read the instructions about dropping the fuel tank to get access to the in tank fuel pump to replace it, which in some cars makes the replacement procedure a HUGE P.I.T.A. and start thinking ,...hey Ill just tap into the fuel line and install one of the outside mount electric fuel pumps and avoid all that work, FORGETTING that the defective in tank fuel pumps going to significantly restrict fuel flow, as its still in the fuel line in the tank
http://www.harborfreight.com/40-piece-h ... 67578.html
clear vinyl 3/8" tube is worthless for anything but testing, but its great for testing because you can see the fluid travel thru it during testing
many guys will go the cheaper route with standard fuel line and hose clamps and that will work in many applications,but if you go this route of using rubber type fuel line ID STRONGLY suggest the better quality 300 psi rated fuel line thats compatible with alcohol in the fuel, most hydraulic hose supply and performance shops have it at only slightly higher cost. my brother -in-law ran two parallel sections of 3/8" inside diam, 300 psi rated fuel line along the route of the factory fuel lines, and mounted the fuel pump on rubber bushings to reduce noise back on the rear inside pass side frame next to the fuel tank, and mounted the fuel pressure regulator up on a custom fabricated bracket that bolted to the rear pass side intake manifold
the existing fuel lines basically follow the upper inside edge outer surface of the pass side frame from the fuel tank to the engine compartment, and duplicating this route will keep the lines well away from the headers
properly sized and fabricated braided fuel line of the correct size is ideal
http://www.youtube.com/watch?feature=pl ... uIoAa5RRBs
MY brother-in-law decided to go with the electric fuel pump and bye-pass regulator and install a fuel pressure gauge, the pump will be mounted on the frame near the fuel tank, the fuel pressure regulator placed near to the carburetor on a support bracket, so you can easily see the fuel pressure the carburetor sees at the fuel inlet
READ THRU THESE THREADS
viewtopic.php?f=55&t=4381&p=14833#p14833
viewtopic.php?f=55&t=1939
viewtopic.php?f=55&t=211
viewtopic.php?f=55&t=635
http://www.summitracing.com/parts/hly-1 ... structions
http://www.summitracing.com/parts/hly-12-454-13
do fuel lines yours look like this,
THEY SHOULD match this config.!
for some reason no one reads instructions and thinks the fuel return lines, supposed to be located at the bottom of the regulator and fuel should flow strait thru the regulator from side to side...WRONG! the fuel feeds up from the bottom center, and for some reason i always seem to get more consistent results with the lines hooked up as posted in the picture
BE AWARE THE FUEL PRESSURE REGULATOR MUST BE HOOKED TO AN UNRESTRICTED FLOW RETURN LINE BACK TO THE TANK TO ALLOW THE FUEL PRESSURE REGULATOR TO FUNCTION AND YOU MUST VERIFY THAT RETURN LINE IS UNRESTRICTED, IF THE RETURN LINES BLOCKED THE REGULATOR WON,T FUNCTION, BUT THE FUEL PRESSURE GAUGE MUST BE ON THE SAME SIDE OF THE FUEL PRESSURE REGULATOR THAT FEEDS THE CARBURETOR, the FEED FROM THE FUEL PUMP FEEDS THE LOWER CENTER PORT, THE LEFT SIDE IN THIS DIAGRAM FLOWS UNRESTRICTED BACK TO THE FUEL TANK, THE RIGHT SIDE FEEDS THE CARB AND FUEL PRESSURE GAUGE
http://www.keenparts.com/pages/Catalog3 ... &year=1974
It is best to run the tank as low on fuel as possible prior to removing the tank.
1963-74 Models
Disconnect the battery cables at the battery.
Remove the gas cap and the filler neck boot from the top of the tank. Disconnect the drain tube.
Raise the vehicle and support it safely with jackstands.
Remove the spare tire compartment (if applicable), spare tire, and spare tire carrier.
Loosen the U-clamps and separate the exhaust systems at the transmission crossmember. Disconnect the muffler support brackets and slide the exhaust system rearward.
Remove the fuel tank strap bolts and disconnect the gauge unit wiring.
Disconnect the fuel lines and allow the fuel to drain into a clean container.
Unbolt and remove the tank support. Lower the tank, rotating it toward the front of the vehicle to remove it.
Installation is the reverse of the previous steps.
having a few basic meters,gauges etc. helps
MULTI METER
INFRARED TEMP GUN
TIMING LIGHT
COMPRESSION GAUGE
PRESSURE/VACUUM GAUGE
READ THESE RELATED THREADS AND LINKS
READ THIS
http://autolabscopediagnostics.com/fuelpump.htm
http://www.corvettefaq.com/c3/sending/sending.html
http://www.mamotorworks.com/corvette/su ... el-tanks-1
http://www.corvettemagazine.com/tech-ar ... placement/
viewtopic.php?f=55&t=211
viewtopic.php?f=55&t=1939
viewtopic.php?f=55&t=635
viewtopic.php?f=55&t=58
viewtopic.php?f=55&t=6105&p=18854&hilit=fuel+filters#p18854
http://garage.grumpysperformance.com/index.php?threads/c3-corvette-not-getting-fuel-to-carb.11668/
viewtopic.php?f=80&t=8505&p=32546&hilit=1974+corvette+tank#p32546
viewtopic.php?f=55&t=7787&p=28271&hilit=flex+fuel+line#p28271
viewtopic.php?f=55&t=4381&p=16285&hilit=flex+fuel+line#p16285
BTW I WONDER IF VERY MANY GUYS BOTHER TO READ INSTRUCTIONS
http://www.jegs.com/i/JEGS-Performance- ... 2/10002/-1
heres a fuel filter I see some guy installed on his 750 holley carb equipped car and he wonders why he runs out of fuel in third gear,think about it, hes got a fuel filter rated at 130 gallons per hour , certainly adequate...until you realize hes using a manual fuel pump that produces maybe 9psi and the filter flow rates rated at 75 psi, , more than 8.3 times the pressure, so hes likely getting 1/6-1/8th the flow at 9 psi
I came over to help diagnose the problem,so we started on a step by step isolate and verify approach to the problem.
(1) the first indication was the car had good ignition spark and spun over with the started but the carburetor didn,t seem to be getting fuel fed from the fuel tank,
(2) so we confirmed the fuel tank was more than 1/2 -to-3/4 full by looking into the rear fuel fill access door in the rear deck, with a flash light.
(3) removing the fuel line from the carburetor and cranking the engine on the starter, while we had a 6 ft section of 3/8" clear vinyl tubing and a hose clamp to extend the fuel line into a 2 litter bottle so we would not spill and fuel showed we were getting zero fuel pressure at the carburetor inlet.
(4) so we know its got fuel in the tank but its not reaching the engine, so we know either the pumps not working or the feed to the fuel pumps blocked.
(5) The next step I took is disconnecting the fuel feed line into the fuel pump inlet port (which resulted in fuel draining out slowly but I was not sure the line was clear, and I hooked a temporary section of 3/8" vinyl fuel line to the fuel feed line going back to the tank and used my air compressor to pressurize the fuel feed line from the tank,for testing which resulted in a mass of bubbles bubbling up in the tank, and obviously indicating the fuel feed line was fairly clear and the fuel strainer sock in the tank was not seriously blocked. removing the air pressure resulted in in a very slight increase in fuel drain rates, probably resulting from the fuel sock in the fuel tank being slightly less clogged from the recent surge of air pressure flowing thru in the reverse of normal fuel flow direction.
looking into the tank with a strong LED light showed years of accumulated crud so we decided to order a new tank and fuel gauge sensor assembly.
(6) now this is a fair indication the fuel lines fairly free so the next step was to use an adapter fitting in the fuel pumps inlet port with a 6 ft section of 3/8" clear vinyl tubing and a hose clamp to extend the fuel line into a 2 liter bottle we filled 3/4 with fuel to test if the fuel pump would suck and pressurize fuel, as expected the fuel pump proved to be defective as it would not move the fuel.
(7) so the choice at this point is to replace the existing manual pump
or replace the manual fuel pump with an electric fuel pump.
HAVING SOME BRASS, FUEL LINE TEST FITTINGS TO USE WITH THE CLEAR VINYL TUBE, IT HELPS WHEN TESTING BUT SWAP TO REAL FUEL LINE ONCE YOUR ACTUALLY INSTALLING A FUEL SYSTEM
keep in mind this corvette is not going to be used for anything but cruising , so he has zero interest in anything but a nice looking corvette that runs smoothly, and has good passing power on the high way, he has zero interest in racing, our concern here is simply getting the car to run correctly , in stages as he can aquire the required components and allow the cars engine too make decent power in the 1200rpm-5000rpm power band, he has several issues but we will be replacing the ENTIRE fuel system, tank, lines, fuel pump,regulator, intake and carburetor..
ONCE we got all the lines, fuel pump and fuel pressure regulator installed my brother-in-law wanted to take the car for a test drive....it ran like crap , because of several reasons, the main one is a rusty old fuel tank full of loose crud , that will soon be replaced (ITS ON ORDER) so we installed the fuel pressure gauge on the line running between the regulator and the carb and found we had 9 psi of fuel pressure, adjusting the fuel pressure to a much more reasonable 5 psi made a HUGE improvement in the cars power.[/size][/b]
BTW, while it doesn,t apply here in this particular case, one factor I see guys ignore at times is when a in tank fuel pump goes bad, guys read the instructions about dropping the fuel tank to get access to the in tank fuel pump to replace it, which in some cars makes the replacement procedure a HUGE P.I.T.A. and start thinking ,...hey Ill just tap into the fuel line and install one of the outside mount electric fuel pumps and avoid all that work, FORGETTING that the defective in tank fuel pumps going to significantly restrict fuel flow, as its still in the fuel line in the tank
http://www.harborfreight.com/40-piece-h ... 67578.html
clear vinyl 3/8" tube is worthless for anything but testing, but its great for testing because you can see the fluid travel thru it during testing
many guys will go the cheaper route with standard fuel line and hose clamps and that will work in many applications,but if you go this route of using rubber type fuel line ID STRONGLY suggest the better quality 300 psi rated fuel line thats compatible with alcohol in the fuel, most hydraulic hose supply and performance shops have it at only slightly higher cost. my brother -in-law ran two parallel sections of 3/8" inside diam, 300 psi rated fuel line along the route of the factory fuel lines, and mounted the fuel pump on rubber bushings to reduce noise back on the rear inside pass side frame next to the fuel tank, and mounted the fuel pressure regulator up on a custom fabricated bracket that bolted to the rear pass side intake manifold
the existing fuel lines basically follow the upper inside edge outer surface of the pass side frame from the fuel tank to the engine compartment, and duplicating this route will keep the lines well away from the headers
properly sized and fabricated braided fuel line of the correct size is ideal
http://www.youtube.com/watch?feature=pl ... uIoAa5RRBs
MY brother-in-law decided to go with the electric fuel pump and bye-pass regulator and install a fuel pressure gauge, the pump will be mounted on the frame near the fuel tank, the fuel pressure regulator placed near to the carburetor on a support bracket, so you can easily see the fuel pressure the carburetor sees at the fuel inlet
READ THRU THESE THREADS
viewtopic.php?f=55&t=4381&p=14833#p14833
viewtopic.php?f=55&t=1939
viewtopic.php?f=55&t=211
viewtopic.php?f=55&t=635
http://www.summitracing.com/parts/hly-1 ... structions
http://www.summitracing.com/parts/hly-12-454-13
do fuel lines yours look like this,
THEY SHOULD match this config.!
for some reason no one reads instructions and thinks the fuel return lines, supposed to be located at the bottom of the regulator and fuel should flow strait thru the regulator from side to side...WRONG! the fuel feeds up from the bottom center, and for some reason i always seem to get more consistent results with the lines hooked up as posted in the picture
BE AWARE THE FUEL PRESSURE REGULATOR MUST BE HOOKED TO AN UNRESTRICTED FLOW RETURN LINE BACK TO THE TANK TO ALLOW THE FUEL PRESSURE REGULATOR TO FUNCTION AND YOU MUST VERIFY THAT RETURN LINE IS UNRESTRICTED, IF THE RETURN LINES BLOCKED THE REGULATOR WON,T FUNCTION, BUT THE FUEL PRESSURE GAUGE MUST BE ON THE SAME SIDE OF THE FUEL PRESSURE REGULATOR THAT FEEDS THE CARBURETOR, the FEED FROM THE FUEL PUMP FEEDS THE LOWER CENTER PORT, THE LEFT SIDE IN THIS DIAGRAM FLOWS UNRESTRICTED BACK TO THE FUEL TANK, THE RIGHT SIDE FEEDS THE CARB AND FUEL PRESSURE GAUGE
http://www.keenparts.com/pages/Catalog3 ... &year=1974
It is best to run the tank as low on fuel as possible prior to removing the tank.
1963-74 Models
Disconnect the battery cables at the battery.
Remove the gas cap and the filler neck boot from the top of the tank. Disconnect the drain tube.
Raise the vehicle and support it safely with jackstands.
Remove the spare tire compartment (if applicable), spare tire, and spare tire carrier.
Loosen the U-clamps and separate the exhaust systems at the transmission crossmember. Disconnect the muffler support brackets and slide the exhaust system rearward.
Remove the fuel tank strap bolts and disconnect the gauge unit wiring.
Disconnect the fuel lines and allow the fuel to drain into a clean container.
Unbolt and remove the tank support. Lower the tank, rotating it toward the front of the vehicle to remove it.
Installation is the reverse of the previous steps.
having a few basic meters,gauges etc. helps
MULTI METER
INFRARED TEMP GUN
TIMING LIGHT
COMPRESSION GAUGE
PRESSURE/VACUUM GAUGE
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