Electrial Problem

c_forshaw · #1 (**permalink**) 02-24-2002, 12:59 PM

I seem to have a real problem. I have a braided fuel line from the electric fuel pump to the carburetor. When I turn the ignition key on, the car will not start. I just clicks. When I turn off the key, the fuel pump continues to run. If I touch the braided fuel line to the block, small sparks fly and the fuel pump stops, but if I stop touching the block, it will start running again. The battery has a full charge. Is the car not starting somehow related to the fuel pump excess run time? Do I have a short somewhere? Have a blown a fuse, or worse shorted out the fuel pump? This is all really frustrating (as are all electrical problems)!

Back in Black · #2 (**permalink**) 02-24-2002, 01:16 PM

Don't even THINK about starting it or any more work until you have at least one right there with the safety pin pulled, and you ready to hose the engine down. The ss line should not spark ! It sounds like maybe a ground problem, is the motor properly grounded to the frame? Is the fuel pump grounded to the motor? Or is it grounded to the frame? (If no to these questions, then be sure to properly ground, if yes, then clean your ground connections and use some vaseline, etc.. to keep corrosion at bay) After dealing with the ground questions, ....
Maybe you have shorted the fuel pump or have wires crossed somewhere, so that the fuel pump only operates correctly when you turn the key off (I assume this is a new build up or you have recently added the electrical fuel pump) I would think you may have the pump wired wrongly, if it is new? It should have it's own circuit, not daisy chained off of the starter wiring, for instance.

I also assumed that there is no fuel pressure when the motor turns over ? Anf that you mean that the motor does not turn over at all? This *clicking* would indicate wiring error or a shorted part ? and that the starter is in the wiring error loop maybe.

Do not EVER remove the fuel line if there is any chance it is still under pressure, especially on a hot motor, or if the battery is still attached !!

Maybe others have hands on experience with this problem.

Chuck Hurley · #3 (**permalink**) 02-24-2002, 02:24 PM

For almost certain you have a bad ground from the battery to the engine block and/or a bad ground from the battery to the frame of the car.

Check the negative terminal of the battery and confirm that there is a heavy wire going to the engine block. It should be at least the diameter of your little finger. The negative side of the battery should go directly to the engine and several small braided type grounds should go to the frame from the engine block.

While installing the new engine in my Cobra guess what was the only line I forgot to connect and guess what the symptons were?

You can easily burn up a wiring harness as the small ground wires try to carry the starting current and are incapable of doing so.

Don't just visually check, grab and pull to make sure that what looks like a wire that is connected is firmly connected.

Good Luck

c_forshaw · #4 (**permalink**) 02-24-2002, 02:56 PM

Back in Black:

This is not a new build. I have been doing a refurbish job on a newly purchased older Cobra (1985). I had taken off the headers to have some work done on them and took the spark plug wires off to aid the removal. I needed to turn over the engine to push oil and metal shavings out the opening for the oil pressure sending unit (this is a whole different story). Well, I remembered to disconnect the coil wire, but forgot to reconnect the plug wires. Since all 8 wires were lying all over the top of the engine, sparks really flew. This incident was the beginning of my problems (car won’t start and continuous running fuel pump).

Back in Black · #5 (**permalink**) 02-24-2002, 03:44 PM

Did the electrical fuel pump work prior to this, even on the old motor? If so, it sounds like you have some fried wires from the ignition flare up. Get in there and look at any fusible links in the harness, look at fuses, look at connectors...if any wires look a bit *melted* that's where to begin work. Use an Ohm Meter, and test continuity on any suspect wires, as well as the ground connections mentioned by Chuck and I. Get a really long set of test leads, so you can check long wires.

Again, be REALLY careful about the fuel lines, and go get two big gas/electrical rated xtinguishers first!!!!

OH, and if at all possible, use a magnet on a good soft wire or string, to grab the metal particles !