ok.. i have a 92 v6 camaro automatic... it have been completly gutted ecm harness motor is all gone has a carbbed sbc. she is about built and geady to fire off just have a few minor wiring things to finish up but my fuel pump is not coming on with teh key.. it will not prime or come on. i looked at a wiring diagram and there looks to be some thing called a fuel pump/oil pressure switch sender... wired in line and from what i can tell it wont give the fuel pump power unless the ecm is reading the motor has oil pressure... i just need to know where this is located or how to by pass it so the fuel pump will come on then the key is in the run position... i would rather not jsut run it with a switch or wire it to an igntion hot i wanna try and keep from hackin up this car as much as possible... Please help!

 

When you start the car, after a few seconds the starter turning the motor will provide oil pressure, and thus the pump will come on, and the car will start. So you don't have to do anything at all really, just start the car. May take a few cranks the first time, for the bowls in the carb to get filled - after that, the fuel bowls will always be full, and car will start.

If you want, you can do what I did....

I took the fuel pump wires off the oil pressure sending unit, and connected a relay inbetween them, added a ground and a hot-in-run (used the factory fuel pump relay.

So what happens, is when the key is on, the hot-in-run energizes the relay, connecting the two wires from the oil pressure sending unit together, making the pump run.

I did this because I've had an occasion where the OPSU went bad, and thus no fuel pump. Also, I had an instance where the OPSU went bad, and the fuel pump ran constantly even without the key until my battery was dead.

But for now, you don't have to do anything - it'll come on with oil pressure.

Did you use a return-style regulator like the Mallory 4309?

Did you use a geomtery corrector for the TV cable (if auto)?

 

i dont have a oil pressure sensor... and if the fuel pump relay was in the engine bay then it is gone... it was stripped b4 i got the car.... and i just want to the pump to come when i turn the key to run... so if you could help that would be great!

 

So just wire in a relay as I described - the OPSU system had a wire from the pos battery (actually from the fusible link terminal beside the battery) that had an inline 10amp fuse, then ran to the OPSU, then out of the OPSU to the fuel pump. So just run a wire from the fusible link terminals with an inline 10amp fuse, to a relay, then out of the relay to the fuel pump - then a hot-in-run and a ground to the relay and you're set.

 

the fuel pump relay is/was in the engine bay, if its gone you need to wire a new one in there. you can hardwire your fuel pump to a switched ign source, but thats never a good idea.

 

Where should I grab the fuel pump wire at? Is it only inside the vehical or does it pass thru the fire wall?

 

so mabey i missed something. but didnt you say you put a carbed sbc? in which case you need a mechanical pump on the block...right?

 

you dont need a mech pump, you can run the stock one.....with a return style regulator. otherwise youll overpower the carb floats.

it comes through the firewall at the c100 connector. thats the one on the driverside, around the same area as the fuse panel under the dash. its the only solid grey wire. but like i said, i highly DONT recommend just wiring the fuel pump to and ign source. it would be ok for just getting the engine to run to make sure it does, but not a long term thing. you need to wire in a relay.

 

and for clarification, the fuel pump was wired into the oil pressure sensor incase the fuel pump relay failed while driving. the oil pressure sensor would keep the fuel pump running as long as there was oil pressure.

 

well now i know lol. thanks! i didnt know such a thing existed

 

yeah def needs a relay no worries. it will have one. and thank u i will hunt that grey wire down.

 

i have somewhat of a problem... i dont have a grey wire coming out of the bulkhead connector on the drive side fire wall... there is one but it is part of the plug that plugs into the wiper motor. i have three wires with no home.. but i ran power to all three and no fuel pump... any ideas?

 

i found it under the dash... nit what i wanted but i guess it will work