Fuel pump, what controls it?

[fbodlovr]

We have been having some issues with the fuel pressure lately. I have a seperate fuel gauge that I connect to the test port directly. WHen I turn the car on, it shows no fuel pressure, but when I start cranking it climbs up, and then the car starts. Wouldnt this be a bad fuel pump? I put in a new walbro 340 the other day, but havent tested fuel pressure because it was storming when i was finishing up. ANother thing is, what controls the fuel pump? Does it just kick on when the ignition comes on, and then the computer controls it once the engine is started? Im not hearing it when I simply turn the igniton on, which is another reason I think there might be a wiring issue with it. We use to be able to hear it, but it was random. Also, If the computer controls the pump once its on, does the hot wire kit kind of bypass that making it pump ALL the time?

Please help, because I think this might be a problem as to why the car is sputtering at higher rpm due to a lack of fuel.

 

[Jerryl]

See attached. I would verify the relay and grounds first and go from there.

 

[SLOW_85]

To keep it simple. If the relay is out, it will default to the oil pressure sender to activatethe pump. There is a test lead to the driver's side of the alternator. Mine appears to be green. Apply 12 volts to it and the pump should prime. You can also apply 12 volts to the wire off the relay going to the pump. That will tell you if it's the relay. Sounds like the relay is bad.

 

[fbodlovr]

I hate to say it, but that picture is a little hard for me to understand. And, where is the relay at still?

 

[cool 84]

Slow85 is right. It's most definately the relay. If the relay goes out, the car has a backup which is the oil pressure sender. It will turn the pump on once the car sees oil pressure but will crank over longer than normal since it has to get oil pressure first. The relay is on the passenger side inner fender.

 

[SLOW_85]

Good Source

http://www.gnttype.org/maint/8485sens.html

#13, passenger side fenderwell.