While I was doing some repair/cleanup work on the engine in my 1980 Malibu, I decided to switch the carb, vacuum harness, thermal vacuum switches, canister, hoses from my '81 Cutlass parts car onto the Malibu, since the parts on the Malibu were in rough condition (thermal vacuum switches broken, vacuum lines plugged, etc) while the Cutlass parts were intact and in good shape. The carb that came off the Cutlass had been sitting for over a year, but it came off a car that ran fine. The fuel lines from the pump to the carb on both cars were seized and twisted, so I got some tubing, and fabbed up a new line. I also replaced the fuel pump with a new stock replacement 2 line (1 inlet, 1 outlet) fuel pump.
When I got the engine back together and fired it up, it ran fine for a few seconds, then I noticed fuel leaking from around the accelerator pump plunger, and fuel bowl vents, the engine started running rough, with black smoke from the exhaust and it died. At that time, I assumed that I had some carb issues, due to it sitting for over a year, with old gas in it, and it being a 35 year old carb. I took the carb off, and took it to a local rebuilder. He completely rebuilt the carb and corrected a couple of other issues with it during the rebuild. I brought it home, installed it on the car, cranked it up, and it fired up right away, and ran great for about a minute, then I started getting the flooding issue again. Fuel was leaking out around the accelerator pump plunger, and out the fuel bowl vents, and the engine stalled.
I called the rebuilder, and he said that maybe some dirt from my fuel pump/line replacement had gotten into the carb, and caused the needle & seat to stick open. He suggested disconnecting the fuel line, running the engine until the carb was dry, then reconnecting the fuel line, and have someone crank and start the engine while I gently tap the front of the carb with a plastic screwdriver handle. Well, I tried that twice this morning, and I still have the same problem.
I noticed that when I loosen the fuel line at the carb, I have a lot of fuel spraying out, at what appears to be higher than normal pressure.
I called the rebuilder back, and he said to pull the carb off, and bring it back to him, and he'll check it. When I mentioned the high fuel pressure/fuel spraying out when I loosen the line, he said that he has seen a few defective fuel pumps over the years, where the fuel pump manufacturer installed internal parts from a 3 line pump (1 inlet, 1 outlet, 1 return) in a 2 line pump body, and that the 3 line pumps usually run at a higher pressure (10-12PSI, as opposed to 5-6PSI for a 2 line pump). He suggested hooking up a pressure gauge to the new pump, and measuring the pressure, but I don't have a pressure gauge. He said that I could try gravity feeding the carb from a container above the carb, and see if I still have the flooding issue. He said that there should be enough fuel pressure under gravity, for the engine to idle, and it should tell me if the issue is with the carb, or the fuel pump.
My question is-does this sound reasonable? Has anyone else here had a similar experience? Any ideas? The engine ran OK with the carb and fuel pump that were on it when I got it, but the carb was really crusty, and I switched because the parts from the Cutlass were in better condition. I wasn't expecting to have this problem, and I just want to get the car to run properly.
Sorry for the long-winded post. Thanks in advance.
When I got the engine back together and fired it up, it ran fine for a few seconds, then I noticed fuel leaking from around the accelerator pump plunger, and fuel bowl vents, the engine started running rough, with black smoke from the exhaust and it died. At that time, I assumed that I had some carb issues, due to it sitting for over a year, with old gas in it, and it being a 35 year old carb. I took the carb off, and took it to a local rebuilder. He completely rebuilt the carb and corrected a couple of other issues with it during the rebuild. I brought it home, installed it on the car, cranked it up, and it fired up right away, and ran great for about a minute, then I started getting the flooding issue again. Fuel was leaking out around the accelerator pump plunger, and out the fuel bowl vents, and the engine stalled.
I called the rebuilder, and he said that maybe some dirt from my fuel pump/line replacement had gotten into the carb, and caused the needle & seat to stick open. He suggested disconnecting the fuel line, running the engine until the carb was dry, then reconnecting the fuel line, and have someone crank and start the engine while I gently tap the front of the carb with a plastic screwdriver handle. Well, I tried that twice this morning, and I still have the same problem.
I noticed that when I loosen the fuel line at the carb, I have a lot of fuel spraying out, at what appears to be higher than normal pressure.
I called the rebuilder back, and he said to pull the carb off, and bring it back to him, and he'll check it. When I mentioned the high fuel pressure/fuel spraying out when I loosen the line, he said that he has seen a few defective fuel pumps over the years, where the fuel pump manufacturer installed internal parts from a 3 line pump (1 inlet, 1 outlet, 1 return) in a 2 line pump body, and that the 3 line pumps usually run at a higher pressure (10-12PSI, as opposed to 5-6PSI for a 2 line pump). He suggested hooking up a pressure gauge to the new pump, and measuring the pressure, but I don't have a pressure gauge. He said that I could try gravity feeding the carb from a container above the carb, and see if I still have the flooding issue. He said that there should be enough fuel pressure under gravity, for the engine to idle, and it should tell me if the issue is with the carb, or the fuel pump.
My question is-does this sound reasonable? Has anyone else here had a similar experience? Any ideas? The engine ran OK with the carb and fuel pump that were on it when I got it, but the carb was really crusty, and I switched because the parts from the Cutlass were in better condition. I wasn't expecting to have this problem, and I just want to get the car to run properly.
Sorry for the long-winded post. Thanks in advance.
