@MG1952: “dramatic warning light” - that’s funny.
Hey Stevef,
Sorry to hurt your tender feelings. I am wrong all the time but tend to get over it. As to electronics I am often correct. I never say I know it all.
To satisfy my curiosity I just connected this fuel pump
http://www.autozone.com/autozone/accessories/Airtex-Products-2-5-to-4-PSI-25-to-30-GPH-electric-fuel-pump-for-vintage-classic-carbureted-applications//N-25jp?itemIdentifier=963381_0_0
correctly and incorrectly and it failed to operate unless the polarity was correct. Honestly, I thought it would work either way.
I need clarification. Why not install the pos of the battery to the pos cable for the car, which coincidentally should go to ground? Wont the Terminals not allow you to incorrectly install the battery. The biggest danger I see would be in jumping the car if metal bumpers are touching. Confused! edit Sorry I thought the guy meant reversing the polarity of the battery.
Speculation without specific information about the pump is a losing proposition. Google is a wonderful tool for answering these types of questions.
This online vendor has specific instructions for installing its product, all of which are listed as -ground, in +ground applications:
https://www.pegasusautoracing.com/document.asp?DocID=TECH00072
The Airtex E8902 mentioned by RN will work in a +ground application, but is 6v.
The Airtex E84259 12v works in a +ground application. It looks a little over sized to me.
The OP should research his particular pump.
Mr. Knox, Kudos for testing your theory, more so for reporting the results.
@MTraveler - it also sounds like the output pressure is an issue for this car, not just positive vs. negative ground, is that addressed in those listings?
Pegasus has listings for small carbureted engines.
https://www.pegasusautoracing.com/group.asp?GroupID=FUELPUMPLOW
Airtex also has recommendations, but isn’t as thorough about indicating what will work with a +ground.
http://www.airtexproducts.com/
The Airtex E8902 seems to have ideal specs., but is 6V.
It works fine at 12 volts. I have used it to pump down fuel tanks for many years, most recently I emptied an 18 gallon tank on a boat. When rebuilding carburetors I can bench test the float setting.
Looks like “MoMini” has left the room and left us in suspense.
Do not attempt to isolate the pump body from ground. The body must be properly grouded to prevent the possibility of a static discharge.
And I strongly recommend against reversing polarity. Just as the electrode in your hot water tank at home functions based on flow in a particular direction, so does your pump assembly. And you also might inadvertantly create a “hot” circuit through the gasoline that you’d be better off without. I strongly suspect that the pump is designed to not compromise the grounding of the tank…don’t play games with this one.
Return this and get the proper pump. The kid at the counter made some assumptions based upon some basic DC motor theory. But I don;t recommend that you make ANY assumptions when dealing aith a tank of gas.
Thank you all. The manufacturer recommended I return the pump. I remembered an article about changing polarity for positive ground british cars to negative ground and looked it up. It is really quite simple (I have not done it yet) and will allow any negative ground accessory to be used. It should take about 5 minutes. I think that will be my solution rather than buy a $150 pump.
Changing the system over to negative ground is not that difficult except for the radio, if so equipped…
Perhaps the Autozone guy meant that you could switch the polarity on your car. Naaahh, probably not. He’s probably not aware that you can do such a thing. Take a look at this online article. http://www.ndmmcc.org/negconv.htm Follow the directions, and Bob’s your uncle.
Sorry I got here late.