If I can't hear the fuel pump . . .

[long board]

The 911 wouldn't start this morning. I can't hear the fuel pump. There are 2 relays in the fuse box, assuming that is the problem, how do I know which one is bad?

[Paulporsche]

We need more info. What year is your car? Are there only 2 relays in the box? Is one of them red? Where are they located?

You can try switching them and try starting. You should also check the fuel pump fuse and insert something thin in the prongs of the relays to spread them slightly before you reinsert and retry.

[long board]

Whoops, I guess that would help I have a 77 2.7 with CIS. There are 2 relays and 1 is red. The fuse looks good. I tried switching them, but it didn't do anything. The relays are located on top of the fuses in the fuse box.

[Paulporsche]

The red one is the fuel pump relay. Try spreading the prongs. Check the wiring. Also check the round connections that push into the bottom of the dash under the steering wheel.

It's possible your ignition switch is bad, or maybe the plug in connector behind the fuel distributor/air flow sensor. Is your battery OK?

[porschett]

Isn't there a green electric plug behind the fuel head you can unplug? With this unplugged, turn on the ignition. You should hear both pumps turn on.

I think with only the ignition on and the green plugged in, you won't hear anything unless you push down on the air flow meter.

At least that's how it is on my 87 930.

[long board]

"Try spreading the prongs. Check the wiring. Also check the round connections that push into the bottom of the dash under the steering wheel. It's possible your ignition switch is bad,"

Tried all that, no luck.

If I remember correctly, the pump is in the fuel tank and it makes some kind of whinning sound when working. I could hear it when I turn the ignition on. It no longer makes that sound.

"At least that's how it is on my 87 930." I think my 77 is quite different and I'm not aware of 2 fuel pumps.

[Jim Williams]

long board,

Your '77 has only one fuel pump. It wil only run either when the starter is turning the engine over, or when the engine is running, provided the fuel pump circuit is still wired as it was as it came from the factory. The pump will under the rear of the tank, not inside.

If you remove the red relay and jumper +12 volts to the #30 pin in the relay socket, you should hear the pump run. If you don't, there are problems with the pump.

[Rufblackbird]

on the '77 2.7L engines, there is a plug behind the fuel dizzy (on the side of the firewall). I don't remember whether or not it was green, though. Unplug it, and once you turn the ignition to "on" you should be able to hear the pump. Or, turn ignition to "on", take off the air box cover, and push up on the air flow plate and you should hear the fuel pumping.

In case you don't know where to push up, it's that round metal disc in side #1 in this diagram.

http://www.pelicanparts.com/911/911_Parts/1974-75/2-3-1.JPG