Club 80-90 Forums

Since changing from a mechanical fuel pump to the JK electric one with fuel regulator my charging meter has been showing input of 10-11 V and with the lights on even less. Does this pump use a lot of power ? or do I suspect that I need a new alternator or have I connected it up incorrectly. Its a 1900 water cooled 1984 ex German Army ambulance. Any ideas?

Simple way to tell is disconnect the pump (the engine will run for a couple of minutes with the fuel in the carb) and measure the voltage then, preferably with a multimeter and preferably from the heavy live terminal on the back of the alternator. A good reading then (around 13.8 to 14.2 volts) means your alternator is OK and you can then look at other possible issues.

btw, the fuel pump should not draw enough power to drag your voltage down ! (though you never know with JK products )

The pump wouldn't draw enough power to cause any problems you have either wired it incorrectly and affected the alternator wiring. Where did you connect it to? Or knocked off the alternator wiring somewhere, or sometimes it's a coincidence and the alternator has now stopped working.