When I turn off my 90 Bronco 351 it sounds like the fuel pump is still on. It will stay on until I unplug the battery. As soon as I connect the battery the pump turns on again. Can anyone tell me it I need a new fuel pump or regulator or what it may be? Also, does anyone know where to find a fuel pump for less than $140 ??? Any ideas about using an inline fuel pump instead? Thanks for any help.


Alex

 

The fuel pump itself is probably not bad. What has probably happened is that your fuel pump relay is hung up. You will find this relay under the hood on the drivers side in line with several other relays. Try unplugging it, They are a little harder than a fuse to pull out because they have 4 connectors intead of just two. When you pull this relay the pump should stop running. Once you pull the relay you can now test to see if the 12 volt signal that closes the contacts to run the pump is the problem or if the relay itself is just stuck. Look down at the socket that you pulled the relay out of. It will have four connectors that match the spades comming out of the relay.

The 12 Volt signal that actuates the relay rides on the terminals that are the one closest to the drivers side fender and the one furthest from the drivers side fender. When these two show 12V, the relay will close the contacts and allow 12V to pass though on the other 2 connectors. These other two are the one located in the socket whith a relationship closest to the radiator and furthest from the radiator.

Now if you have a volt meter and it shows a 12 volt signal on the signal terminals all the time, then the relay is going to be closed all the time and the pump will run all the time. If it does not have a 12 volt signal but the pump is still running when the relay is plugged in, it will mean the relay is stuck shut and allowing power to pass through it. You can test this by checking the relay for continuity on the two terminals that are across from each other on the relay. These two terminals would form a T if they were closer to each other. A note of caution here. Sometimes when you pull a relay out it will allow the relay to snap back open. and it will seem to test ok. You might then plug it back in and the problem will seem to be gone. But never trust a relay that has stuck once. It is a cheap part, just replace it if in question.
So look for voltage at the signal leads and if you see voltage there when everything else is shut off, then we will discuss that problem more later, as I am much better at diagnosing electrical problems than I am at typing. I really think you will find the relay is bad. If not we will work on in more, later. Good Luck, Larry.

 

Yep, it's probably the relay.

And don't go bargain-basement hunting for the pump OR the relay. OEM lasted you, what, 12 years? Get a quality Echlin relay from Napa or the real deal from the dealer. Ditto for pumps.

Another stuck relay in 2 months is not worth finding a dead battery early in the morning.....pay an extra $10 or $20 now for years of trouble free service.

I'm not trying to sound rude, I'm just trying to pass on to you what I have already learned the hard way.

 

Thanks a lot for the help!! I will try it and keep you posted on my results. Thanks again!

Alex