MG Car Repair: 1980 MGB Loss of Power under Load, fuel pressure gauge, wheel spokes

Question
Hello Howard,

My 1980 MGB runs well except for every once in a while if I am pushing it - gas pedal floored going up a long grade.  That is when I lose power and it feels like the engine is missing.  I hear a ticking/clicking sound somewhat like I used to hear when I was a kid and put a baseball card between the spokes of my bicycle's wheel spokes. The sound is coming from the rear - I think it is the fuel pump.  This condition will gradually go away after I am not pushing the engine.  I do not know what to do to determine what the problem is, but I feel confident you can provide me with procedures to troubleshoot this problem.  Thanks.

Answer
Hi Wayne,
Symptoms can lead you to an area but tests must be run to find a real problem. If your car was brought to me with your symptoms I would need to know exactly what the fuel pressure to the carburetor is at the time of failure. To find this out i would need to connect a "T" in the fuel line at the carburetor and run a long hose out from under the hood and place a fuel pressure gauge under a wiper (be sure to put clamps at each joint) and take the car out to a long grade and get it to fail and read the gauge. Any pressure below 1.5 PSI (at the time of failure) is too low. First check for air leaks in the fuel line between the fuel pump and the tank. If none are found then check the fuel level in the tank and if it is up enough then you probably have a problem with the fuel pick-up tube in the tank.

Most vacuum gauges have a pressure section for checking fuel pressure and they are not expensive. A extra length of hose and a "T" fitting with clamps also are not expensive and all this can be used on any carburetor car.

The rapid clicking of the fuel pump is an indication the pump is drawing air not fuel. Even though an open fuel line can make a pump click more than normal it will not click fast. Air drawn in is the only thing that can cause that. A faulty pump can do that but it will usually do it often and under several conditions.
Howard