Draining Fuel Bladder

[Exhlr8n]

The Comp Coupe had the Staubli quick disconnect plumed to the fuel pump to drain the Bladder.

When I turn the Ignition switch and leave it on the fuel pump runs for a second or 2 then shuts off, only squirts out a little shot of fuel. Shouldn't the pump stay on stay on?
Do I bypass the pump somehow to keep power on, or use a secondary pump to the end of the exiting fuel line?

The line to the Staubli is "T'ed" off of the pump, its the 3 o'clock line in the pic. The Male end that plugs in to the disconnect isn't in pics.

Anyone have experience with the Staubli?

Thanks,

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[Back In Black]

The fuel pump only stays on if the engine is running. On my Gen4, I used a jumper wire in place of the fuel pump relay in the PDC (power distribution center) under the hood. It needs to be 16g wire or better.

Your PDC should be nearly identical to mine. You would put the jumper between D15 and D11 on the diagram.

Relay diagram.JPG

Relay.JPG

[Exhlr8n]

Awesome Back in Black..! That's what I was looking for.

[Exhlr8n]

Looks like the Gen 3 Comp Coupe is different from Gen IV.

I tried jumping 91 and 87 (they were highlighted with yellow) with no luck. Any other ideas?

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[Steve-Indy]

Is the fuel pump fuse (B 22) OK ?

[Exhlr8n]

Yes. The car starts and runs fine. Just trying to figure out how to keep pump on when not running.

[Back In Black]

Your PDC looks identical to mine. Same relay as well.

You have the master power switch on when you're doing this correct?

Pins 30 & 87 on your relay are normally open. When the relay is activated, they close sending voltage to the pump. The upper left yellow marked socket in your photo should be energized when the master power switch is on. If you have 12 volts there and jumper it to the lower right yellow marked socket and the pump does not turn on, then there's some other kind of wiring going on.

Does the car run with that relay pulled?

[Exhlr8n]

Yes master power on, Battery and Ignition switches on, just like if I were to start car. You can hear the fuel pump turn on for 1-2 seconds. Will check if it stays running with relay pulled, but it doesn't power up the fuel pump for the 1-2 seconds when not in, so my guess not.

I will check the top left pin for 12V. I will put a terminal on the jumper wire, I just tried with bare wire, maybe didn't get a good connection.

[Back In Black]

Yes master power on, Battery and Ignition switches on, just like if I were to start car. You can hear the fuel pump turn on for 1-2 seconds. Will check if it stays running with relay pulled, but it doesn't power up the fuel pump for the 1-2 seconds when not in, so my guess not.

I will check the top left pin for 12V. I will put a terminal on the jumper wire, I just tried with bare wire, maybe didn't get a good connection.

Ya, if you pull the relay and don't hear the pump when you turn the ignition on, you should be good to go. You really should crimp terminals on your jumper wire. You won't need to have the ignition on when you use the jumper wire.

I used terminals like this and cut one of the legs off.

sk1_1.jpeg

[Exhlr8n]

I will try it again tomorrow morning.

Thanks

[steve911]

This is the correct way to do it. You can purchase a set of fuel pump relay bypass switches. I haven't seen then individually only as a set. This is what I use on my Comp Coupe in the fall. Summit sells them , Amazon also, I am sure there are others. The grey one is the one for the Viper.
Relay Switches.jpg

[Exhlr8n]

With a proper connection the jumper worked fine. All good. I left a little fuel in it so not to run the pump dry.

I will pick up one of those relays!

Thanks guys, much appreciated..!

[PCH Viper]

Hey Tom,
The ECU shuts off the fuel pump after a few seconds if the motor is not running. Like others, mine has a bypass switch to energize the fuel pump.

It's great that yours is plumbed with the pump out line. Makes things super easy.