Part II: tank drain re:very perplexed on this on e

[jalero]

OK, I'm ready to replace the fuel pump motor.

Been trying to come up with a method to drain the 7/8th full tank.
I thought I had a solution twice, but further thinking, they were not feasible.

My latest is since I can get the pump running: (although it has started the past three days)
to disconnect the outgoing / feed line and pipe to my collection container.

My question is, since the pre-pressure with the key in the 'on' position will never reach it's designed pressure,
will the pump continue pumping or is there a 'timeout' of some sort ?

Any additional ideas on draining tank much appreciated.

thanks, jack

[Tech II]

If you just turn the key to on, the pump will be power for just a few seconds and shut off.....

Like you said, disconnect the line from the filter attach a hose and send it into a gas container.....then, remove the fuel pump relay, and jumper power to the fuel pump.....i.e., jumper G7 to J6........you don't say your year, this is a 2003 Alero....

[jalero]

Thanks Tech II for the schematic.

So you think that the PCM shoots 12v to the relay for a predetermined amount of time ?

I was thinking that a fuel pressure sensor (if one exists) would watch for a specified pressure and shutdown when reached.

If pressure no reached, not shutdown ?

[Tech II]

No, there is no fuel pressure sensor....

If you look at the diagram, the fuel pump relay is controlled by the PCM...

When the key is just turned to on, you will hear the fuel pump run for a couple seconds and then stop...it's kind of like priming the system.....the reason it stops, is because the PCM is not receiving a reference signal from the ICM, because the engine is not cranking/running.....when you turn the key to the crank position, the engine turns over and then a crank signal is sent to the ICM, and the ICM sends a reference signal to the PCM....As long as the PCM sees the reference signal, it will continue to ground the relay......when the engine stops, no crank signal, then no reference signal, and then the PCM no longer grounds the relay....

Fuel pressure is regulated by the fuel pressure regulator on the end of the fuel rail....the pump creates way more pressure than needed, and the regulator lowers it to the correct pressure.....