Fuel pump relay shutting off right after key on.
 

Hi all,

I am trying to finish wiring up a 2.9 L I put in '84 BII. The 2.9 is from a '88 BII.
When I turn on the ignition I hear the ECM relay, and the fuel pump relay. But... the fuel pump relay shuts off after about 2-3 seconds. Any ideas on this? I thought it should stay on.
I just installed the relay as well. It seems the old one blew up, along with my fuel pumps. I get good continuity and power to the harness. Just get that odd behavior. I will be replacing the fuel pumps both on the rail and in the tank in a few days when I have the money. Any insight on this would be much appreciated. Thanks.

Hawkeye :-X22

Do you actually hear the relay clicking off or does the fuel pump just stop running after 2-3 seconds?

It's supposed to do that. It will click back on as soon as the computer senses that the engine is turning.

That's what I was kind of steering towards with my question above.

Relay
 

Thanks for responding guys. My pumps will not run. I do hear the relay clicking on then a few seconds later it clicks off.
Your info helps. I know the circuit is good now at least. The pumps need replacing though. :(

Hawkeye :-X22

Are your pumps in tank or out on the frame rail? You could run jumper wire from the pump directly to the battery to test your conclusions before you start to tear it apart. Just a suggestion.

pumps
 

Good idea. I have put 12 volts to the frame rail pump and it's toast. I don't hear anything from the fuel tank either. I used to hear both running during tests some time ago. ( I don't get to work on my truck everyday due to busy schedule).
Now since I am tracing the troubles I got curious about the actions of the fuel pump relay. You fellas helped me out. I got both my pumps yesterday (New), pretty pricey, I hope they last a long time. I will be trying to get both installed this weekend and then I'll see where I'm at. Once again Thanks for your insight.

Hawkeye :-X22