Fuel Pressure Drops To Zero AfterStartup

[srduster340]

Anyone know why my fuel pressure drops to zero when I start my engine? With switch on the pressure is at
6 psi. When it starts it immediately drops to zero and the engine dies. Mallory 140 pump and regulator. I have a separate switch in the circuit in case I service the fuse Box and need the key on.

 

[67Dart273]

"More info needed."

Was this working ok, and now quit? Did you just install it?

What pump, relay? How did you wire it, fuse, ??????

 

[daredevil]

Sounds like pumps wired wrong. Or clogged filter.

 

[TrailBeast]

Sounds like pumps wired wrong. Or clogged filter.

It very well could be a filter daredevil, good call.
Either that or for some reason the pump shuts down when the car is started.

 

[srduster340]

Just starting the engine for the first time. New Mallory 140 pump and filter. I do have a circuit breaker and relay to fire the pump. The pump is Wired to the fuse Box to turn on with the ignition switch. There is a toggle switch inline the power wire that turns on the pump so I can turn the pump off with the key on if needed. Hope this gives a clearer picture.

 

[demon seed]

Where in the circuit is the fuel pressure gauge installed.. Should be right at the carb.

 

[67Dart273]

Just starting the engine for the first time. New Mallory 140 pump and filter. I do have a circuit breaker and relay to fire the pump. The pump is Wired to the fuse Box to turn on with the ignition switch. There is a toggle switch inline the power wire that turns on the pump so I can turn the pump off with the key on if needed. Hope this gives a clearer picture.

Can you hear it run when the pressure drops?

What size wire did you use?

You sure it has a good ground?

Did you use a relay?

 

[RustyRatRod]

Get a test light on the hot wire to the fuel pump and lef someone watch it while you try to start it to see of it loses power.

 

[TrailBeast]

Get a test light on the hot wire to the fuel pump and lef someone watch it while you try to start it to see of it loses power.

That would be the very first thing I would do.
I'd probably pop the line off at the carb and do a volume chk on the fuel flow after that.

 

[Frank Mopar]

got a good ground on the pump?

 

[srduster340]

Thanks for all the help fellas. I had the fuel pump Wired to a key on circuit in the fuse Box.I ended up simply wiring the fuel pump directly to the battery with a high amp toggle switch to command the relay to turn on the pump.Problem solved.

 

[nothingbutdarts]

Thanks for all the help fellas. I had the fuel pump Wired to a key on circuit in the fuse Box.I ended up simply wiring the fuel pump directly to the battery with a high amp toggle switch to command the relay to turn on the pump.Problem solved.

If you truly are only turning on a fuel pump relay with the toggle switch, you did not need to use a "High Amp." toggle switch. The relay is the only item that has the "High Amps." running thru it. The "latch" part of the relay is a low amp. circuit.

Glad you got it figured out!!