View Full Version : "hot wire" for fuel pump

08-24-2005, 05:45 PM
Hi everyone,
I am new to this site, just got a nice 87 GN this week. It is a car that my daughter and I are sharing. Funny thing is I have not seen it since Monday! We can hardly wait to cruise together with my GSX.

I am a fanatic about wiring. Cannot stand substandard electrical and am willing to attack the problem wherever it exist. I understand that the fuel pump hat wire is not that great and I would like to fix that this weekend. I plan on using a relay and work on a good source off the alternator. Does anyone have a link on the best experiences doing this?

08-25-2005, 02:51 PM

However, the kit from Casper's Electronics is plug-n-play and very tidy.

08-25-2005, 07:09 PM
pardon my ignorance, but what does this do ? whats the benefit ? whats the reason for doing this ? Ive heard the "hot wire" terminology and everyone tells me ya need to do this with a new pump, but i dont know why....

08-26-2005, 10:18 AM
Stock wiring is pretty sad for a pump that needs as much current and voltage as the TRs.

The "Hot Wire" is a heavy gauge wire that runs either directly from the alternator or the battery to provide full voltage to the pump. Usually a tank ground strap is also added.

I've seen it take the voltage at the pump from 11.9 volts to 13.2 volts (on my homemade one with a fan relay and some 8 guage wire).

If you look at the fuel curves for the pumps, they have more output at higher voltage ...


for example.

08-26-2005, 12:50 PM
The stock wiring actually has *7* connectors in the line between the alternator and the fuel pump. Each one adding resistance and choking down the power. This does it with one direct heavier gauge wire, one connector on each end, and the stock wiring used as to flip a relay to turn the power off and on.

08-31-2005, 09:31 PM
Thanks Scott and Ken. You guys always come through with the helpful knowledge. That clears it up for me. Thanks again. :)