Fuel Pump Grounding

[62BT7]

I'm now ready to finally (!) replace a defective fuel pump on my '62 BT7. I'll be installing the SU solid state pump that Moss sells, and my solid fuel lines were chopped by a previous owner so the connections will be non-stock. Question: The fuel pump has a post where the power line is attached, easy enough. But near the flange where the square body meets the round protrusion, there's a spade terminal, I assume for a ground line. Easy as well but the question is whether it's necessary to rig a ground wire when the pump itself is a metal-to-metal connection, e.g. the metal body is mounted via two bolts to a metal bracket which is in turn bolted to the body. Grounding seems unnecessary. Thoughts?

 

[Jerry]

I mounted my pump with a rubber pad between the pump body and the frame so the vibration of the pump did not add noise to the car. So I did add a ground wire although it should have still grounded through the bolts. My ground wire goes from the pump to the bolt that holds the pump the car. Not more than 6 inches long.

Jerry
BN4
BJ8

 

[Bob_Spidell]

The pump solenoid--the 'round protrusion'--is (theoretically) electrically isolated from the pump body by a fiber gasket and the rubber diaphragm. However, in practice I've seen them work just fine without the separate ground, probably because the screws that hold the solenoid to the body conduct well enough.

 

[John Turney]

Like Jerry, I also added a wire to mine even though I didn't insulate for noise. I like being able to hear the pump to know it's working, although once I start the engine, I can no longer hear it. Then again, no one has accused me of having a quiet Healey.

 

[Randy Forbes]

I used rubber stand-offs, as the Facet interupter-type pump isn't shy about letting you know it's working.
The ground wire is attached under one (1) stud of the isolator and to its own bolt on the body.

Likewise, once the engine's running, you no longer hear the pump working.

 

[Michael Oritt]

I recommend a separate ground wire to a good ground--Screws through sheet metal are suispectible to corroding or becoming insulated by oil mist from the external lubrication system.

 

[Johnny]

Interesting responses to a simple question, do you need a separate ground to allow the pump to work. Allow me to tell a short story. I installed a new SU pump on my BN7 using the original type bracket thats bolted to the rear bulkhead, which of course provides a ground for the pump. All's well until the bolts came loose then the pump stopped working.
Now the question needing answering is, knowing the fuel pump is about to drop off and drag the ground, or, by adding a separate ground the pump will continue to operate and no longer connected to the car?

 

[Bob_Spidell]

...
Now the question needing answering is, knowing the fuel pump is about to drop off and drag the ground, or, by adding a separate ground the pump will continue to operate and no longer connected to the car?

If I understand the question, yes the pump will operate as long as it has a hot lead and a 'ground' (either through the pump body to the chassis or a wire connected from the solenoid to the chassis).

 

[Johnny]

Yes, but which is safer????

 

[GregW]

Yes, but which is safer????

Mechanical pump.

 

[Bob_Spidell]

Ohhhhhhhhhhhhhhhhhhhhh ... now I get the question.

Yes, it's theoretically safer if the pump falls off to break the connection to ground. But, I can't imagine a pump falling off--unless someone failed to bolt it up properly--and the ground wire is a spade lug on small wire that would probably disconnect itself with the weight of the pump. Plus, the pump banjos should remain secure.

Point taken, though.

 

[why]

yes but when the pump falls off and hangs on only by the hot lead, it will be truly connected to ground. So if you add a metal strap hanging from the chassis to the true ground, the circle will be completed. Although the final determination can only be made when you answer the age old question of whether you walk to school or take your lunch, now if you bought your lunch from Moss as opposed to.........
Jay, '65 3000

 

[TimK]

Another prime example WHY I love this forum!