danialreed

iTrader: (2)

I swapped my car from TBI to carburetor and took out the ECM section of the harness. I have a question on the fuel pump relay. I have all the wires matched up except the green/white wire that was part of the harness removed. I am trying to figure out where to hook it up since all wiring diagrams show it running to the plug for the ecm which is gone. My fuel pump will not run without that relay. If anyone can help me I would greatly appreciate it. The fuse is good and the relay is brand new, and clicks when that green/white wire is connected to a power source. Also the plug to the relay is recieving 12v of power when the key is on. I need to try and eliminate this issue to see if my pump is bad. The pump works when a power source is applied.

vetteoz

iTrader: (13)

You answered your own question
That wire needs to have 12V from the Ign switch when the key is on

If you still have the original fuel pump oil pressure switch in the block
wired up ,the pump will run without the relay as soon as you crank the engine over.
No need for any wiring changes

danialreed

iTrader: (2)

I do have the original oil pressure switch, but the wiring is not all original. According to the diagrams all the gray wires that come off of the OPSU, fuel pump relay are all ran to one gray wire to the fuel pump. The issue is if I connect the fuel pump gray wire to the other gray wires the fuel pump runs constantly when the ignition switch is in the off position. What wire coming from the relay sends power to the fuel pump. They are all supposed to match colors correct? Orange to orange, grey to grey, and so on? I also supplied a keyed power supply to the green/white wire and it still doesn't click when teh key is on.

danialreed

iTrader: (2)

Oh and the car reads oil pressure when started.

danialreed

iTrader: (2)

Does the Orange wire off the fuse by the battery run to the orange wire on the fuel pressure regulator switch harness?

vetteoz

iTrader: (13)

You haven't filled in your profile so have no idea what year you own

Not knowing what wiring mods you did for your swap , you appear to now have batt power on a output wire (gray to pump) that should only be hot with the engine running.
Need to check your OP switch if it is faulty it could be locked in the On position,

That would suggest your relay is kaput. Have you confirmed it actually works?

danialreed

iTrader: (2)

ok so what i gather is all the orange wires meet up, and so do all the grey or tan/wht on your diagram. I own a 91 camaro with a 350 sb. If the OP is stuck in the on position would that be inadvertantly powering the pump forcing it to stay on. I do not have an aircompressor to test the old OP so I am going to buy a new one and see if that works. The relay is brand new and when I supply a 12v hot wire to it, it does still click. Does the green/wht wire matter if I don't have an ecm any longer?

vetteoz

iTrader: (13)

You are not checking if it works ,only that it is not closed and passing power to the pump full time.
Put a DVM across the 2 switch terminals , it should be open and show no connection

That would suggest a problem with the new wire you ran from the Ign,
did you confirm it had 12V at the relay terminal?

Nothing to do the the ECM.
If you want to use the relay you need power from somewhere to turn it on.

Or you can fix the OP switch circuit and it will run the pump as soon as you crank the engine over without needing the relay.The engine will fire up on the fuel in the carb bowls so you don't need the key on prime from the relay that EFI cars do

danialreed

iTrader: (2)

how do you wire it to run off of the OP switch? i'll get out a dvm to check the switch before I order a new one

danialreed

iTrader: (2)

DVM reads infinity when set to 2000 ohm resistance and placed on the terminals of the OP switch, if I am correct this is a bad switch.

vetteoz

iTrader: (13)

As per the diagram .
Hot org wire to one terminal , gray wire in your case to the pump

Infinity is open circuit ; no connection so the switch is good at least when it is off , does not mean it actually works.( can only test that with the engine running )
You now need to find out where the permanent power on your gray pump wire is coming from

danialreed

iTrader: (2)

ok so i can run the orange wire from the fuze to the orange of the OP switch, and the grey from the OP switch to the fuel pump.
If that is correct the car will not stay running.

vetteoz

iTrader: (13)

So the obvious thing to do would be to check if the pump will run when you join the org straight to the gray wire?

If it does , the switch is faulty
If not you got problems elsewhere with the pump wiring

danialreed

iTrader: (2)

I replaced the OP switch and wired orange to orange and the grey to the fuel pump and it is running like a champ. Thanks for all the help.

vetteoz

iTrader: (13)

As the Man from the A Team said
" I love it when a plan comes together"

wm_sorg

Does anyone have the wiring diagram? I need to bypass the relay to test power at the pump. If I pull the relay (which one on the block?) what position or color should feed power to?

Regards,
WS

OrangeBird

iTrader: (1)

Here ya go wm_sorg, your 1991 wiring diagram.

Looking at the relay, you'll see a red wire coming from the relay's connector that ends in a "pigtail". That wire is a pump test / prime wire, without pulling the relay put +12V to that to send power to the pump. I don't recall which of the three relays is the pump, but it'll be the one with the large red, orange, and grey wires, and the smaller dark green/white and black/white wires. If you do pull the relay, it'll be the large grey you'll want to apply your +12V to.

wm_sorg

You rock! Many thanks.