Help, adding a fuel pump cutoff

[808_c1500]

I want to adda fuel pump cutoff switch to hide in the cab for security purposes. Wiring to the fuel pump relay, which wire should I add the switch inline with? Terminal D on the relay is 465 DARK GRN/WHT and goes to the ECM is this the best wire since it energizes the relay coil or should I switch 440 ORN wire to the relay?

 

[evilunclegrimace]

Year, make, model?

 

[PlayingWithTBI]

Terminal D on the relay is 465 DARK GRN/WHT and goes to the ECM is this the best wire since it energizes the relay coil or should I switch 440 ORN wire to the relay?

You'll need to go up further so the Oil Pressure Switch doesn't turn on the Fuel Pump as well.

 

[Caman96]

Wild guess… 88 C1500.

 

[808_c1500]

91 chevy c1500 350

 

[808_c1500]

You'll need to go up further so the Oil Pressure Switch doesn't turn on the Fuel Pump as well.

Can you tell me more? If I switch off one of the two wires I listed, won't that make the fuel pump inoperable and the starter just crank without any fuel? How does the oil pressure switch make the fuel pump still work if the fuel pump relay is essentially off?

 

[PlayingWithTBI]

How does the oil pressure switch make the fuel pump still work if the fuel pump relay is essentially off?

Take a look at your schematic - the Oil Pressure switch is wired in "Parallel" with the Fuel Pump Relay, not "Series" so, either or both can turn on the fuel pump. This is GM's way of giving you redundancy for fuel. If one goes out, the other will still give you fuel. Plus they are fed directly from the battery through that Fusible Link "F" so, you don't even have to have the key on to allow the Oil Pressure Switch turning on the pump.

I know this for a fact since one time when I was priming my oil pump with a primer tool and drill (distributor out of the engine), all of a sudden, my pressure gauge on the Throttle Body jumped up to my set point of 20PSI.

 

[Caman96]

91 chevy c1500 350

I was thinking 80(eighty)8_c1500.
I looked through all these but nothing for fuel cut-off, but still some good ideas:

http://www.dlcparts.com/images/BoschGuide.pdf

 

[evilunclegrimace]

IMO. The quickest, easiest way to make the pump not run is to put a switch in the hot line that feeds the pump. Everything will work as designed but the fuel pump will not run until the circuit is completed when you close the switch

 

[808_c1500]

Take a look at your schematic - the Oil Pressure switch is wired in "Parallel" with the Fuel Pump Relay, not "Series" so, either or both can turn on the fuel pump. This is GM's way of giving you redundancy for fuel. If one goes out, the other will still give you fuel. Plus they are fed directly from the battery through that Fusible Link "F" so, you don't even have to have the key on to allow the Oil Pressure Switch turning on the pump.

I know this for a fact since one time when I was priming my oil pump with a primer tool and drill (distributor out of the engine), all of a sudden, my pressure gauge on the Throttle Body jumped up to my set point of 20PSI.

Ah yes I think I see it. I'm not literate at wiring diagrams but I see the pink/blk wire from the oil pressure switch routing power around the fuel pump relay.

Can you suggest another location for my manual switch?..I know they are many ways to install a switch cutting off an electrical component which will make the truck inoperable. I mainly want to cut fuel pump so I can hear someone cranking the truck from my inside my house since I live on a quiet dead end street where no outsiders should be loitering.