fuel pump relay or not

[my454s10]

i have rewired my whole truck..should i put a relay on for my holley blue pump and my head lights..????

[bowtietd]

Not sure about the headlights but definately use one for the fuel pump.

[Indiana]

Can you give me a high level idea of what the relay does for this application?

[my454s10]

how do i install a relay on the pump

[Scotty_S-15]

A relay for the fuel pump would take the load off the ignition switch, and any other switches you might have in the system, such as oil pressure switch. I just wrote a whole thing on the use of relays....

........ See \"Relay or Switch\" in electrical forum.

[my454s10]

how many should i use for the whole truck...lights..fuel pump..ingition..etc????

[Scotty_S-15]

On 2004-06-08 10:23, my454s10 wrote:

how do i install a relay on the pump



Specifically, to wire a fuel pump, I\'d take a wire that was \"hot\" with ignition on, run it thru a manual, preferably hidden switch, then thru an oil pressure switch, then to the coil of the relay. A power line can then be run from any power junction point, thru a fuse, then thru the contacts of the relay to the fuel pump. A nice option would be a momentary switch to bypass the oil pressure switch, so you can fill up the carb without cranking the engine to get the pump working.

.... You should always have an oil pressure switch to prevent massive flooding of engine if you inadvertently leave ignition switch on, with engine off, hence pump running. Do I have one..... No..... http://www.s10v8.com/images/smilies/icon_eek.gif http://www.s10v8.com/images/smilies/icon_biggrin.gif but that\'s the right way... http://www.s10v8.com/images/smilies/icon_smile.gif

[Scotty_S-15]

On 2004-06-08 10:39, my454s10 wrote:

how many should i use for the whole truck...lights..fuel pump..ingition..etc????



The more, the merrier. Again, each takes some load off the ignition switch. I think the ones you\'ve mentioned are good ideas, along with one for the fan, if you\'ve got an elect. fan. If you\'re doing major re-wiring, it\'d be nice (& easy to troubleshoot) it the were grouped together in a bank, with an adjacent fuse block. Then you\'d just need to run one large power line to the fuse block/relay area.

[my454s10]

im not concered about leaving the switch on and flooding the carb..i will just install a relay....can i install relay to the wire the power my ingition swith and it weill act like a relay for the pump and lights and ingition or should i get a different relay for each ..

[Scotty_S-15]

The only thing about flooding the carb by leaving the electric pump running when engine is off is this: You don\'t know it\'s flooding. I know I\'ll NEVER leave my pump on with engine off.... AGAIN.... did it once, but NEVER again. Who knew I was actually filling the CYLINDERS with gasoline. http://www.s10v8.com/images/smilies/icon_eek.gif I never even smelled gas. I went to crank over the engine, a brick wall. Hydraulic\'d the engine. Luckily, no bent rods, no permanent damage.

......... THAT\'S why ya gotta be careful...

[Scotty_S-15]

Using one relay to control fuel pump, lights, fans, etc. would work OK. But, depending upon the overall amp load, and the amp rating of the relay, the relay may become overloaded. A

......lso, it\'s best to put a fuse in a line as early as possible (closest to the source) and by using only one relay, you\'d need to either use additional fuses as each smaller wire branches out, or leave them relatatively unprotected by a large fuse before the relay.