I just swapped a 305 tune port to a 87 trans am i just bought and swapped the whole wiring harness over aslo. I used all the relays from the car i took the engine from becuase it ran when i pulled it. When i turn the key i can hear the relay click but no power to the fuel pump unless i hard wire it from the battery straight to the pump. I know if the oil pressure switch isnt hooked up it wont give you power to the pump. where is the oil pressure switch at? What else could this be?

 

Oh and also i forgot to say that when i jumper the orange wire and tan/white wire together i still get no power and the orange wire does have power to it if that helps more

 

I have the same problem still plauging me today..
And I cant come to a conclusion if its electrical or
the pump itself..

The location of the oil pressure switch is right
above your oil filter, you can easily spot the
connection comming off your harness on the
driver-side.

I thought that too was my problem, But it was
plugged-in. The only other thing I can think of is
a ground issue since you just stated the pump
worked before the swap.

But like everyone else stated to me, Pumps go out
at damndest times, I hope that is not your case

 

Well actually i just put in a new pump and it works perfect when i hard wire it straight from the battery at 50psi, but i dont know if running it straight from the battery messes with the computer? Cuz the engine doesnt run that good. It sounds like its missing a cylinder but it ran perfect when pulled but im pretty sure the gas is bad, its like the color of apple juice so thats probably the problem with the engine not running that well

 

You dont want to directly run your pump
from your battery for several reasons. If Im
correct the car will not tell the pump to prime
before start-up, the gas gauge will give a false
reading and you could easily burn the pump up
in a short amount of time. Also the car will most
likely run sluggish until the pump functions with
the car.

If the pump actuates with power, the problem
lies in the electrical somewhere throughout the car.
Double check everything