1970 240z electric fuel pump question

[Patcon]

My 2 cents

Go back and review post #6 and give the electrical engineer what he asked for...

[Blitzed]

Hi Patcon,

Will do as soon as the fuse box is reinstalled in the car. As with most hunt for the unicorn it requires access to the harness. 

Assume this fuse box will carrier the same fuse location to check for continuity and same side of the fuse?

 

 

[SteveJ]

5 minutes ago, Blitzed said:

Hi Patcon,

Will do as soon as the fuse box is reinstalled in the car. As with most hunt for the unicorn it requires access to the harness. 

Assume this fuse box will carrier the same fuse location to check for continuity and same side of the fuse?

 

 

Yes, the fuses are in the same locations.

The outer labels on the stock fuse box cover (Acc, Ign, Bat, Ammeter) give the power source.

[Blitzed]

SteveJ,

Hope all is well. 

With all reinstalled and connected. Key in the off position. 

The green wire is dead from both side of the fuse holder. The black / white has continuity from both side of the holder. Right side registers a larger number .19 on the meter left side lower .12 ???????

[SteveJ]

Was the fuse pulled when you tested?  The readings sound like it wasn't.

Likely, the green wire is the one that goes to the back of the car where the fuel pump would reside.

@cgsheen1 was giving you good direction. You can get the inertia switch here: https://www.amazon.com/gp/product/B07RBK4873, but you will probably need to modify it. I bought one, and like the reviewers on Amazon said, the switch is wired to a normally open contact. It should be on a normally closed contact. It wasn't too difficult for me to move the pin, but I'm used to doing things like that.

You might want to look around a little more for a green wire with an inline fuse. It may be covered with electrical tape. That is how it was wired from the factory. I'll see what I can find with poking around in the wiring of my car this weekend. I have a sneaking suspicion I know where the wire for the fuel pump is routed in the wiring harness.

[Blitzed]

Hi SteveJ,

Yes fuse was pulled but operator error forgot to reinstall the battery ground. Once the battery ground was installed, close to zero (.1,.2) on the left side for the black and white and larger reading on the right side. Green is dead both sides, yes un-terminated wire at the fuel tank connection.

[w3wilkes]

Picture in this thread might help.

240z Electric Fuel Pump Installation - Page 3 - Carburetor Central - The Classic Zcar Club (classiczcars.com)

The electric fuel pump circuit in the 240z's is all ready to go. You can activate it by jumpering the blue taped connector in the picture in the link. That jumper should also have the impact sensor in the jumper loop referred to by @cgsheen1 above. When Datsun did this they did a much more sophisticated job as referenced above by @Zed Head.

Edited August 10, 2021 by w3wilkes

[Blitzed]

Hi w3wikes,

All good data. I've located the connector at the console, no issues there. Sorry, not familiar with the term "jumpering" . How do I jumper the console connector to activate the circuit?

my last instructions were to meter the fuse and connector and determined which side of the fuse had the juice. left side of the fuse, no juice. Right side juice, so the connector is not part of an existing circuit.

Never received a you're screwed, so just assume so.  From another post about relay's on the passenger kick panel , assumed I'm missing components to complete the circuit. 

Are you suggestion another path to power the connector?

Thanks for the info. 

 

[Zed Head]

To jump a circuit just means to connect two things, in electrical terms.  A jumper wire is the wire used to connect two points in a circuit.  So when w3 says just jumper the blue taped connector he means connect it to some other point.  Probably a power source.  I don't know, exactly, what to jump it to either, but, apparently, the wire that heads back to the pump area is in that blue taped bundle.

All these words and just a fraction closer.  Might as well find that naugahyde wrapped blue taped bundle.  You'll be even closer.

[w3wilkes]

One of the wires in that connector is hot when the key is in the run position. When I was figuring this out here's what I did, the green wire is the jumper I've been referring to;

This will give you power to run the electric fuel pump at the tank. Other than putting the impact switch in this loop it's all you need. You don't need all the relays Datsun put in their tech bulletin. I've been running this way since 2017 with no trouble.

[Blitzed]

Bless you friend, a solution. 

Thank you for the post and help. 

[Zed Head]

Got my threads mixed up.  Posting 71 info in a 70 thread that has been converted to 73.

Never mind.

 

Edited August 11, 2021 by Zed Head