1991 camaro rs w/305 TBI having an issue.....fuel pump continues to run after car is off. i replaced the pump a few months ago, everything fine since then. recently repaired the tranny and replaced the oil pressure sending unit, and put in a throttle body spacer. dunno what it could be. i know the pump gets it's power through the OPSU, could it be something to do with that?

 

On my 1989 Camaro 305 FI Vin E (TBI) there is an 'Oil Pressure Switch' located just above the oil filter. I believe it has 3 wires. Normally that switch should provide power to the fuel pump motor ONLY if the oil pressure is 6 PSI or more. However if that switch gets sticky or goes bad in some other way it would probably allow the fuel pump motor to continue running.

Also, if the 'Fuel Pump Relay' sticks in the ON position it would energize the fuel pump.

On my vehicle that 'Fuel Pump Relay' is located on the driver's side, under the hood, attached to a 'standoff bracket' on the firewall located near the left front fender. It is the second relay from the fender. It has 5 wires that plug in with one connector.

The 'Fuel Pump Relay' is normally energized by the ECM. So normally the ignition would need to be in the RUN or CRANK position for the ECM to energize that relay.

The 'Oil Pressure Switch' is NOT energized by the ECM. It is only dependent on the oil pressure reaching 6 PSI or more (when it is operating properly). I have seen other posts that state that the switch will sometimes leak and then not function properly.

 

thanks. i'll see what works.