1984 4 cylinder fuel pump problem (Page 1/1)
Wayne Renninger NOV 25, 06:51 PM
Was hoping someone with an 1984 4 cylinder could help me with my problem. Replaced fuel pump and now does not stop running with key in the on position, The 84 has 2 differant connectors from fuel pump . A single pink wire and a double tan and black. I test light the tan wire on the 2 wire and get low light , stays on. I want to know how bright the light should be and if it stops after a short time. When I hot wire the gray wire the car starts and runs, but the the pump does not stop running before I start and stays on after shutting the key off. I've replaced the oil pressure sending unit, and the relay. It clicks when i turn the key on. .Need help. I pulled the tank back out the pump empties the tank with a jumper box. The gauge was pegged 9 o'clock I think the screen was blocking the float, Should the gauge read from empty to full if I hook up the whole assembly outside of the tank, moving the float up and down. I also tried 3 differant ecms, and replaced original prom to anothet ecm. Thanks in advance, it;s making me nuts!
buddycraigg NOV 25, 07:29 PM
It was hard for me to follow along with your story.
So the fuel pumps runs non stop?
Dukesterpro NOV 27, 03:55 PM
Okay, Let me help with this. Two thing control your fuel pump in a 84.

(1) The engine computer switches a ground which fires a relay (mounted in the engine bay, on the firewall directly behind the drivers seat) that sends 12V to your pump.

(2) The Oil Pressure sending unit (back of the block, down low, between the engine and the trunk) has a bypass that sends 12V to the pump when oil pressure is present.

First thing to do is unplug the relay:

If The Pump Keeps Running its in the oil pressure circuit, go inspect the oil pressure sender, make sure someone didnt unplug it and jam a paper clip in the bypass (the plug sockets look like this |_| the two parallel ones are the bypass the horizontal is for the gauge) If its plugged in, unplug it and see if the pump stops. If it does, you have a bad sender.

If The Pump Shuts Off, inspect the relay to ensure the contacts aren't stuck closed. It happened to me. If they are stuck closed replace the relay.

If the relay is okay. Check the ALDL port under the center console to see if someone jammed a paper clip in the fuel pump test port.


If none of those resolves the issue, report back and we will go a little deeper.

Dont take anything else apart, your will only make this worse.

[This message has been edited by Dukesterpro (edited 11-27-2023).]