Fuel Pump Wiring

[Weasel73240Z]

I'm not getting 12V at the electric fuel pump of my 73 240Z. I'm trying to find the fuel pump wiring/relay under the dash. Anybody know where it is, what it looks like, etc.?

[EScanlon]

AFAIK, the fuel pump does NOT have a relay in the 73. Just a 20A fuse in the fuse box area in an in-line fuse holder. It's also only powered through the "RUN" portion of the ignition switch.

FWIW

E

[Weasel73240Z]

I looked in the fuse panel, but I wasn't looking for an in-line fuse. I'll check when I get home.

Thanx

[beandip]

Because the pump is only regulated by the ignition switch the pump will run as long as the ignition is turned on. Therefore if for some reason you have a accident and or fire , if you do not turn off the switch the pump will continue to pump fuel. It is a vary simple mod to add a pressure switch into the circuit that will only activate the pump when there is oil pressure. This way if the engine stops or the oil pump fails the flow of fuel will stop. Also there is a inertia switch available that would do the same thing if you have a wreck. You will find the in-line fuse , EScanlon mentioned, on the passenger side just below the dash and close to the console . There is a bundle of wires there. Gary

[kray-z-1]

The wiring from the elec fuel pump goes to a relay on the passenger side of the dash - mine was a Bosch 20/30 amp with 5 spades on it.

From there it goes to an in-line fuse that should be inside the console next to the fuse block. My in-line fuse melted - leading me to the relay. I got a new relay at NAPA - replaced the fuse - replaced the pump and things were good.

Hope this helps.

[beandip]

What year Z was this ? I completely replaced my entire wiring in my '73 and there was no relay on the pump circuit. My build date is 8/73 However there is now. But this is a different issue. Gary

[Carl Beck]

The 73 240-Z's did NOT come from the factory with an electric fuel pump, until the last part of the production year.

At first Nissan had great problems with the 73's and their Emissions Carb.'s. This in turn lead to a series of "fixes" that were developed over time and implemented in Stages.

If one has an early build date car - and that car wasn't taken into an Authorized Dealer for the Modifications Programs - it is quite possible to have a 73 with no electric pump, no in-line fuse and no relay etc. - - or some odd combinations of all or some of the items.

On many of the early cars - the mechanics just activated the existing pre-wiring for the electric pumps by putting a jumper wire in place... if the mechanic was at all smart he put an in-line 20amp fuse in the jumper. There is a green wire and a I think a red/blue wire in a female connector that has three wires in it, - - it was taped up to the outside of the harness with blue tape - that has to have two male ends from the jumper wire - it's in the harness behind and to the right side of the fuse block..

Anyway - the point is you never know what your going to find on a "73 240-Z" in regard to the fuel pumps... So it should not be a surprise if Weasel73240Z doesn't have a relay, nor if he's having a hard time finding the in-line fuse that "should" be there.

FWIW,

Carl

[ktm]

Carl, my May 1972 build '72 240z has the in-line fuse holder for the fuel pump.

[xray]

Bo-

Would you mind posting a pic of the fuse holder and its location? Mine is 5/72 also, and either it doesn't have one or I'm mis-identifying it....

Thanks,

Steve

[ktm]

I'll post a picture when I get home. It's located behind the heater control panel/fuse box.

[EScanlon]

Here you go.

First pic shows the in-line fuse holder AND the fuse holder HOLDER on the side of the fuse box.

Second pic shows more detail. In the case of this vehicle the fuse holder had already been marked by the original installer.

Third pic shows the connection for the Fog Lamps. (Not a part of this thread, but where you would insert a switch to activate power to the fog lamp connectors at the front of the car.)

HTH

E

[Carl Beck]

Hi E. / everyone:

That first picture looks like the installer was an Authorized Dealer using the Factory supplied parts. The little clips on the side of the fuse block were also included in the Factory 73 Modifications Plus Program package here in the US. I don't know if the Factory Actually installed the same parts later in the production year ot not - they easily could have..

It is nice that one is clipped to the side of the fuse block - but I haven't seen too many of them done that way (even by the dealers mechanics taking short cuts and leaving the fuse holder next to the other two in the wiring harness behind the dash.

Usually- if you find an in-line fuse holder - that wasn't installed by the Dealer - the installers didn't have the same color coded wires to use.. or the aftermarket fuse holder simply had black wires on it..

FWIW,

Carl B.