Diabolic

Hello there! I just joined today because I'm trying to help my 17 yr old neighbor get his first car running. It's a 1985 Comaro with a 2.8. It had the key broke off in the lock so I replaced the cylinder. He thought the fp was bad because you couldn't hear the pump prime when the key was turned to the "on" position. I ran a jumper wire from the battery and fot 40psi on my fp guage. Now, about my problem. I noticed 2 relays on the DS firewall by the brake booster. I tried to swap them out with eachother because they looked the same but still got no voltage to the pump. Then I noticed an identical relay mounted up front by the battery and mounted right to the side of the radiator on the pass side. It has 4 wires, heavy guage orange, then thin black, then thin black with a green stripe, finally a heavy brown wire. The center 12 guage black wire has 12V with the key on. No other wire gets any voltage. If I jump that wire directly to the thin black/green stripe wire, the fuel pump primes and the car runs great! Fires right up! I replaced that relay thinking it was bad, but as soon as I plug the harness back in to the new realy, the pump wont prime.

Now, what is that relay? I hear no mention of it when I search. I realize a relay needs a ground, 12V constant, 12v switched, and 12v out to the item it powers(fuel pump) Should it have 12+volts constant to the large orange wire? Does that make the large brown wire a ground? So as it sits, the colored wires are dead and the small black wires will energize the pump. It makes zero sense. Can anyone pleas help me out? I'm a Ford guy trying to help a Chevy guy so cut me a little slack.

Diabolic

Is there such a thing as the fuel pump prime relay? That's what happens when I jump the two wires, it primes the pump.

John in RI

iTrader: (167)

Here's a wiring Shematic for the 85 V6....... The relay is mounted to the firewall - closest to the Wiper motor.

P.S. Be sure to install a new fuse ! It's loacated on the engine bay frame rail - next to the battery !!!

Diabolic

I have that wiring diagram as well. There are two large, flat relays mounted right by the booster on the firewall. One is the elec fan relay and the other seems to be for the A/C. The relay I speak of looks identical to the other two, but is located on a bracket nect to the radiator on the pass side. If the jump the center two wires together with the key on, then the fp primes and the car will fire right up. I'm thingking the large orange wire that has 0 voltage shoulf have a constant 12V and the large tan wire runs to the fuel pump. I just can'd understand why the pump primes when I connect the two small black center wires. I'm going to look for that fuse. Maybe that's why the orange wire has no power. Maybe once I get that worked out then the relay will function properly. Does no one else have this relay next to the battery? It has 4 wires going to it and appears to be mounted to a factory bracket.

John in RI

iTrader: (167)

The fuel pump relay is exactly where I described it. The relay that you are asking about appears to be the MAF relay.




Be sure to check ALL of the In-Line fuses near the battery.

85purp

I scanned my 85 Camaro with a 2.8 v6 as well. and the code I got was fuel pump relay faliure. How do I fix this?

84z96L31vortec

saw your post about the 1985 camaro fuel pump relay, I have the same problem and sure would appreciate if you would share with me how you resolved it, my name is Bob email is kabobp@juno.com, phone 973-722-1858 and I'm located in Northwest Jersey. Thanks, Bob