Fuel Pump Stays On

[Saint Bernie]

When I turn the ignition on without starting the fuel pump stays running. I replaced it with a stock AC Delco. Did I screw something up? Is something telling the fuel pump to stay running? (fuel pump relay, etc)
Confused in Huntsville

 

[aminga]

The ECM should prime the pump for 2 seconds before startup. What all got changed?

 

[jdpolzin]

Check for pinched wires.

 

[Saint Bernie]

I changed the fuel pump out with a stock replacement. I don't know if it was staying running before that. It was a pretty simple swap out. You would figure it would be hard to screw it up

 

[SHADOWII]

Disconnect the batt./pull the fuse and check for continuity thru the relay to the fuel pump connector. That should tell you if the contacts are melted together or the coil is shorted.

 

[mikestertwo]

A bad/shorted oil pressure sender will do that also. Pull the connector off of the oil pressure sender and see if the pump stays running.

 

[Saint Bernie]

Thank you for the replies. I have replaced the fuel pump relay and the oil pressure sending unit and it still stays running. I also disconnected the lead to the oil pressuere sending unit and it still stays on. I replaced the pump with the Delco replacement, should I drop the tank and see if I did anything wrong swapping it out??

 

[mikestertwo]

Pull the pump relay and see if it still runs. Is the pump hotwired?

 

[Saint Bernie]

I pulled the relay and it stopped. Reconnected it and it resumed. Is it sucking air in the tank? Sounds like I need to drop the tank and see if something is not hooked up right.

 

[Saint Bernie]

When I say still running means you can hear the pump buzzing in the tank and a blowing air like a vacuum leak sound under the hood that I cannot isolATE.

 

[mikestertwo]

The noise you hear under the hood with the pump running is the fuel bypass in the pressure regulator. That is normal. If the pump stops when you pull the relay then the problem is in the relay circuit. You have replaced the relay...the only thing left is the computer. The relay is energized off of pin A1 on the computer. Try another computer.

 

[Saint Bernie]

Are we talking the chip or the whole ecm?

 

[mikestertwo]

Are we talking the chip or the whole ecm?

We're talking the ecm. It may have a shorted driver. I'm not aware of any chip that keeps the pump running after the key is turned on and engine not started. They all have a prime timer in them. What chip are you running?

 

[SHADOWII]

Try putting a clamp on the fuel return line from the regulator, incase the diaphram went.

 

[Scott Atk]

I had same problem years ago. Took a new ecm to fix it.