TBI fuel pump relay options

[bp71k5]

I'm doing a pretty extensive rewire on my truck and I'm looking at replacing the stock fuel pump relay to match all the other relays I'm using (headlights, fans, etc). Any reason I can't use a standard painless type 30A relay. I'm wondering why the stock relay is so large compared to other relays. My fuel pump is a Bosch external pump.

 

[dave w]

I'm doing a pretty extensive rewire on my truck and I'm looking at replacing the stock fuel pump relay to match all the other relays I'm using (headlights, fans, etc). Any reason I can't use a standard painless type 30A relay. I'm wondering why the stock relay is so large compared to other relays. My fuel pump is a Bosch external pump.

The standard "cube" relay offered by Painless, "Works fine / Lasts a Long Time for most areas in North America. I used the "cube" relay underhood for a couple years here in the Pacific Northwest. But I've learned not to use the "cube" relay for underhood uses ever again.

Sooner or later the exposed contacts of the "cube" relay will corrode, (much sooner in my area with nearly 5 feet of rainfall a year). Delphi invested lots of money to develop a nearly weatherproof sealing system for the factory relays. I would be nuts to use a standard exposed terminal "cube" relay where I live. Visit a junkyard in my area for the proof of how well the factory relay contacts holds up against the outdoor elements.

dave w

 

[bp71k5]

The standard "cube" relay offered by Painless, "Works fine / Lasts a Long Time for most areas in North America. I used the "cube" relay underhood for a couple years here in the Pacific Northwest. But I've learned not to use the "cube" relay for underhood uses ever again.

Sooner or later the exposed contacts of the "cube" relay will corrode, (much sooner in my area with nearly 5 feet of rainfall a year). Delphi invested lots of money to develop a nearly weatherproof sealing system for the factory relays. I would be nuts to use a standard exposed terminal "cube" relay where I live. Visit a junkyard in my area for the proof of how well the factory relay contacts holds up against the outdoor elements.

dave w

That's a good thing to consider. In my case, I'm planning on moving most of my relays back to the interior side of the firewall so the weather may not be an issue. I can still use the GM relay, but it would be nice to standardize if possible.

 

[dave w]

Inside the cab is a good location for the "cube" relay. The relay your considering will work fine for a fuel pump.

dave w

 

[bp71k5]

Cool. I'll just try it and change it back if I ever need to.

 

[4X4HIGH]

Why not hit the junk yard and pick up a bunch of factory fuel pump relays and use them for your other purposes as well? I'm guessing you're wanting the smaller relay though since you asked why the stock one was so large.

 

[eagle mark]

The standard "cube" relay offered by Painless, "Works fine / Lasts a Long Time for most areas in North America. I used the "cube" relay underhood for a couple years here in the Pacific Northwest. But I've learned not to use the "cube" relay for underhood uses ever again.

Sooner or later the exposed contacts of the "cube" relay will corrode, (much sooner in my area with nearly 5 feet of rainfall a year). Delphi invested lots of money to develop a nearly weatherproof sealing system for the factory relays. I would be nuts to use a standard exposed terminal "cube" relay where I live. Visit a junkyard in my area for the proof of how well the factory relay contacts holds up against the outdoor elements.

dave w

I wonder if liquid tape would help you in the exposed areas? I have used it before and it,s virtually clear, needs a couple coats though.

 

[bp71k5]

Why not hit the junk yard and pick up a bunch of factory fuel pump relays and use them for your other purposes as well? I'm guessing you're wanting the smaller relay though since you asked why the stock one was so large.

Yep. I'm already using 5 of the small ones and have the sockets to go along with them. Space under the dash is getting kinda tight. But there are a couple relays I can't move behind the dash so maybe I'll use the sealed relays for those.

 

[GMC Truck]

Go to your local Johnson/Evinrude dealer and ask for OMC terminal grease this is a black almost tar like grease for relay connectors used on outboard motors. This grease is completly waterproof and will not wash off even with saltwater, should you ever decide to drive into the ocean? BTW the tilt/trim "cube" relay for the same outboards are sealed if you wanted a waterproof relay.

 

[Big6ft6]

Isn't one reason for having relays under hood to keep the high-amp wires outside of the passenger compartment?

 

[eagle mark]

Isn't one reason for having relays under hood to keep the high-amp wires outside of the passenger compartment?

Never thought about that... Good Point!

I know the old Scouts have the main charge wire from altenator through the firewall to an amp gauge and back through the firewall using a bulk connector. Luckily the bulkhead connector fries out first or the fire would be passenger comparment...

 

[bp71k5]

I think for most of the relay powered stuff, its to keep the long runs of large wire to a minimum. Also, the fuel pump in my case isn't very large. The reason I asked is because I'm installing a new fuse block that has a connection for a fuel pump already in it.

 

[mrt93257]

Just make sure its rated for continuous use whatever you use