I've installed my share of electric fuel pumps using a simple toggle switch to apply power but I'm now in the midst of attempting an install one using a relay and wiring it directly to the ignition switch.
I originally hooked all the relay pins this way:
30 = Fuel Pump
85 = Ignition Switch (to the terminal that has power when the key is turned to ON and ACC)
86 = Ground
87 = Fused line to Battery
87a = Starter Cable side of the starter solenoid (has power when cranking engine)
My intention is so the fuel pump would receive power from the ignition when the key was turned to ON then when the key is turned to START it will receive power from the starter side of the solenoid during cranking. However when I connected the hot line to 87 I blew the inline 20 amp fuse so I tried it again and again the fuse blew. OK let me rethink this. I decided to change up the wiring configuration on the relay since it was obvious I did it wrong.
So I decided to reconfigure the wiring this way:
30 = Fused line to Battery
85 = Ground
86 = Ignition Switch (to the terminal that has power when the key is turned to ON and ACC)
87 = Fuel Pump
87a = Starter Cable side of the starter solenoid (has power when cranking engine)
Before I connected 30 to the battery I connected the fuel pump directly to the battery just to see if the pump came on and it did, no leaks too, good. Ok everything else connected, now connect 30 to the battery, fuse did not blow. I turned the key to ON then to START the engine turned over but the cranking sounded weird so I turned the key to OFF. I let it sit for a couple seconds then turned the key back to ON then to START. Dead, nothing. I turned the key to OFF then to ON and went to check on the pump to see if it was on. It was off.
I used a multi meter to check power to the starter side of the solenoid when the key was turned to START. No volts. Checked the positive side of the coil too. No volts. Checked the ignition switch terminals with the key ON, no volts...yeah, I think I just fried the ignition switch.
I studied the relay semantic and realized it doesn't have the 87 open, 87a closed like most Bosch relays.
It has a 87 open, 87a open because 87a is connected to 87. What the heck. Ok I'm going to buy another relay with the standard 87 open, 87a closed and I'm pretty sure I need to buy a new ignition switch too, I just hope I didn't burn up the electronic voltage regulator I just installed.
I'm considering just hooking up the fuel pump through a toggle switch so I don't burn up another ignition switch but this is my wife's car and would really prefer the pump to turn on when she turns the key on. Aside from not installing the oil pressure safety switch feature what am I doing wrong here.
I originally hooked all the relay pins this way:
30 = Fuel Pump
85 = Ignition Switch (to the terminal that has power when the key is turned to ON and ACC)
86 = Ground
87 = Fused line to Battery
87a = Starter Cable side of the starter solenoid (has power when cranking engine)
My intention is so the fuel pump would receive power from the ignition when the key was turned to ON then when the key is turned to START it will receive power from the starter side of the solenoid during cranking. However when I connected the hot line to 87 I blew the inline 20 amp fuse so I tried it again and again the fuse blew. OK let me rethink this. I decided to change up the wiring configuration on the relay since it was obvious I did it wrong.
So I decided to reconfigure the wiring this way:
30 = Fused line to Battery
85 = Ground
86 = Ignition Switch (to the terminal that has power when the key is turned to ON and ACC)
87 = Fuel Pump
87a = Starter Cable side of the starter solenoid (has power when cranking engine)
Before I connected 30 to the battery I connected the fuel pump directly to the battery just to see if the pump came on and it did, no leaks too, good. Ok everything else connected, now connect 30 to the battery, fuse did not blow. I turned the key to ON then to START the engine turned over but the cranking sounded weird so I turned the key to OFF. I let it sit for a couple seconds then turned the key back to ON then to START. Dead, nothing. I turned the key to OFF then to ON and went to check on the pump to see if it was on. It was off.
I used a multi meter to check power to the starter side of the solenoid when the key was turned to START. No volts. Checked the positive side of the coil too. No volts. Checked the ignition switch terminals with the key ON, no volts...yeah, I think I just fried the ignition switch.
I studied the relay semantic and realized it doesn't have the 87 open, 87a closed like most Bosch relays.
It has a 87 open, 87a open because 87a is connected to 87. What the heck. Ok I'm going to buy another relay with the standard 87 open, 87a closed and I'm pretty sure I need to buy a new ignition switch too, I just hope I didn't burn up the electronic voltage regulator I just installed.
I'm considering just hooking up the fuel pump through a toggle switch so I don't burn up another ignition switch but this is my wife's car and would really prefer the pump to turn on when she turns the key on. Aside from not installing the oil pressure safety switch feature what am I doing wrong here.
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