fuel pump cut-off

1985 500sel gray market. The car is having problems keeping battery charged as we don't drive it very often anymore. but everytime that I have to charge battery, the security ssytem must be disabling the fuel pump. I figured this out by checking current at fuel pump. I was able to lock/unlock doors from trunk with the key to reset security system and it would work again. However the last couple of times that has not worked. I bypassed a wire directly from battery to fuel pump to start the car, somehow by doing this it reset the system to a state where it would work again. No w a week later it has happened again. I was able to again use the wire from battery to fuel pump to start and after a few times of starting engine, the system reset itself. I would like to just get rid of this 'security' feature, I don't believe anyone is going to steal my 1985 car that has 160k on it anyway. Is there anyway to straight wire the fuel pump past the security system?? The way I have been doing it causes pump to run all time instead of intemittently. I found a "fuel control unit" under the passenger floor mat with many aftermarket wires pulled to it. I have traced most of them and can post picture if needed. Two of them go to intake manifold to some type of sensor that buzzes. There is two power wires. three grounds. any ideas?? None of the aftermarket wires go to the fule pump. It doesn't even seem that the fuel control unit is even doing anything.