i have an 85 5.0 efi. lately it has been dieing on me while driving. it seems to me that the fuel pump is cutting in and out. 6 months ago i installed a new pump/ sending unit, tank (mid mount 19 gal) lines and filters. is it possible its a relay over heating or maybe i got a bad pump? i dont drive this truck hardly ever but someone ran into my daily driver and wrecked it pretty bad so while its in the shop im forced to rely on my truck. and since i have had to start driving it every day it has developed this issue. up until the last 2 weeks of daily driving this truck has never givin me a single ounce of trouble.

 

The guys on this forum are good but I think a little more information might be needed.

How many fuel tanks? When does the problem start? I.E. when it's idling, when it's cold, when it warms up, when it rains or when the gas gauge reads below 1/2 a tank. It obviously runs somewhat because you're driving it. When it's about to die, does it sputter when you push the gas pedal then idle when take you foot off the gas?

 

^agree

I would double check your work, mainly check the wire connectors, whats to say its not lose? Without the circumstances of the problems occurrence it could be hard to tell what the problem is?

How do we even know that it is the fuel pump? What lead you to this conclusion in the first place?

Can you provide me details on the randomness or pattern and maybe what you have tried?

 

well guys i figured it out, and im kicking myself in the a** over what the reason was. so as i stated the pump/ tank/ filter/ lines are new. and for some reason the new sending unit has decided that 1/2 tank and empty happen to be the same thing! it said i had 1/2 tank which turned out to be the damn thing was empty. i feel like a retard but i guess thats what i get for buying an autozone sending unit/ fuel pump. i think that after i start the restore on this truck im going to a 15 gallon cell and an out of tank aeromotive pump. thanks for the replies

 

Awesome!