Electrical Guys Help - No Power to Fuel Pump, Could it be a bad coil? Options

[vesnyder]

Trying to figure out why my fuel pump is not getting any power and determined the power for the pump comes directly off the coil. The voltage leaving the relay panel is ~12V, but coming into the coil is only about 2-3V - that is with the wire disconnected - with it connected to the coil it is only ~.3V. Is this right? How do I determine if the coil is bad? How much for a new one?

[lapuwali]

My coil + comment was directed at making it work IF you had a carb'd car and IF you really were trying to pull fuel pump power off the coil (which, SirAndy notwithstanding, is a common practice). Since you have D-Jet, you can ignore this comment.

With D-Jet, the fuel pump power is switched through a dedicated relay on the relay board, which is itself switched by the ECU. Power for the coil also comes from a relay on the relay board, which is switched by the ignition switch. If your coil and fuel pump are on the same relay, something is wrong.

When you turn on the key, the fuel pump should come on for a short while (1-2 seconds), then it will turn OFF until the engine is running. So, if you've switched on the key and are measuring fuel pump voltage with the engine off, then it's no surprise the fuel pump isn't running. Aside from the brief prime pulse, the ECU ensures the fuel pump is off while the engine isn't running. If you suspect the fuel pump isn't working at all, then you can try to hot-wire the fuel pump directly from the battery just to see if the pump works. If the pump works but you can't start the car, you need to start the usual no-start diagnostic, which usually should start with the ignition. You should have +12 volts between the coil + and the engine tin with the key turned on. If you don't, there's your no start problem, and it's mostly likely the main relay, or the ignition switch, or the wiring between them.