ChrisZ said:

It is to activate your fuel pump while cranking, after that the altenator takes over, so the fuel pump will not run unless the engine does.

Chris

Thanks Chris but if that is the purpose then it isn't working. I don't have a mechanical pump. My electric fuel pump comes on when the ignition switch is "on" and it stays on. I think the original owner rewired it. The pump power wire appears to be spliced to one of the black/white wires that originally powered the ignition coil. The one that originally ran to the ballast resistor I think. I'll have to take a closer look at all that.

Did you find this info in the 1973 FSM or the 1974 FSM?

  Mikez73 said:

Thanks Chris but if that is the purpose then it isn't working. I don't have a mechanical pump. My electric fuel pump comes on when the ignition switch is "on" and it stays on. I think the original owner rewired it. The pump power wire appears to be spliced to one of the black/white wires that originally powered the ignition coil. The one that originally ran to the ballast resistor I think. I'll have to take a closer look at all that.

Did you find this info in the 1973 FSM or the 1974 FSM?

Mike,

The previous owner may not have used the factory wiring. The 240Zs had wiring for electric fuel pumps even though they used mechanical pumps. The dealers used this wiring for fuel pumps for the service bulletin on the 73s and 74s with the flat top Hitachi carburetors (see Wick Humble's book).

Steve

The original owner did indeed have the pump rewired. There is a red wire from the pump that is connected to the black/white wire that was originally used in the ignition circuit. The electric pump "ON and OFF" wiring is in the 74 FSM. I haven't found the black clad wire on the solenoid in the schematics yet.

In the 74 FSM I see a simple diagram of a circuit with a "choke heater and electric pump cut #1" relay and an "electric pump cut relay #2".

I don't think that my car has either of those relays.

A fuel pump cut relay might be a good thing to have. Or an oil pressure activated cut. With the Webers I'd probably need an override switch for cold starts.

I'll trace that wire down tomorrow.

  GreenZZZ said:

And you wrote docs too! Not sure if this is the latest docs.

http://www.classiczcars.com/forums/showthread.php?t=19934

http://www.classiczcars.com/forums/showthread.php?t=20016

As much as I appreciate the "Plug" Those Doc's are seriously outdated. I wrote the last ones over 4 years ago. I've since change a few thing and perfected building runs, to use less Wire in some areas, less split loom and a better all around design. I really should rewrite that some day.

Seems like every time I write a Doc or do a write-up, the design changes for the better, then I can't change the original post and every one misses it or asks why the next guys upgraded stuff is better. Or something like that.

Anyways, Back on topic.

I'll be installing an electric fuel pump on the green Z after I put the triples on there (Weber 40DCOE's on a long Cannon mani.) And I actually have The fused OEM connector to plug into the plug near the fusebox.

Good thread though, informative so far.

Dave

  Quote

Did you find this info in the 1973 FSM or the 1974 FSM?

Neither, i found this

Chris

Edited May 3, 201014 yr by ChrisZ

  ChrisZ said:

Neither, i found this

Chris

Ok, I read that Chris. Interesting info but no help for Mikey

BTW, I found references to those relays in the 74 FSM.

I don't know exactly what the purpose of the wire is on my car but but it isn't connected to my fuel pump. I found out that the starter doesn't work if it isn't connected though. That kinda throws a wrench into my starter relay plans.

I've come to the conclusion that I need to get my carbs right before I worry about any other projects.

Mike,

What's the build date on your 73? I'm wondering if it didn't get some of the 260Z wiring changes.

It's 2/73 Steve. I reckon that makes it pretty early?

I've got to do something about these carbs before I do anything else. I don't know if you saw my distributor post but I have spark now. I'm having trouble getting it to start though. It's trying but it just doesn't quite catch on. I'm sure the timing is off.

I almost had it going today but I had to stop today because one of the filters was saturated with gas.

I hate to mess with the carbs before getting it running and timed right but there is just too much gas leaking.

I know it's going to be a PITA to replace the gaskets and seals and then adjust the cabs but I think I can handle it.

And getting the carbs adjusted is probably going to be complicated by the timing being off.

I'm really missing EFI now.

Can you post a photo of the relays, in passengers footwell.

If your carbs are spilling fuel like that, you should adress that first, before even trying to get a spark, replace your needle valves and check your float hight.

Chris

  ChrisZ said:

Can you post a photo of the relays, in passengers footwell.

If your carbs are spilling fuel like that, you should adress that first, before even trying to get a spark, replace your needle valves and check your float hight.

Chris

That's what I'm thinking Chris. I've been getting some backfire, more like small pops, through the intake while I'm trying to get it running and I don't want any big oops happening now. My budget is too tight for a mistake like that.

I'm trying to decide on the right kit right now.

I can take pics of the area the relays are in but you'll need to ID them. In fact if I find out I don't need them I might be able to help you out if the relays are what's holding you back and you can't find any. As far as I can tell they aren't doing what the Nissan engineers intended on my car. I'm not a purist at all and this car will never be put back anywhere close to stock as long as I own it.

  Mikez73 said:

It's 2/73 Steve. I reckon that makes it pretty early?

I've got to do something about these carbs before I do anything else. I don't know if you saw my distributor post but I have spark now. I'm having trouble getting it to start though. It's trying but it just doesn't quite catch on. I'm sure the timing is off.

I almost had it going today but I had to stop today because one of the filters was saturated with gas.

I hate to mess with the carbs before getting it running and timed right but there is just too much gas leaking.

I know it's going to be a PITA to replace the gaskets and seals and then adjust the cabs but I think I can handle it.

And getting the carbs adjusted is probably going to be complicated by the timing being off.

I'm really missing EFI now.

Mike, would you stop killing off EVERY half-decent idea I come up with?

About all I have left is to get a cable tracker, detach the wire from the starter, and trace where it runs to. (I've had to do this at work to trace miswired equipment.)

They're great ideas Steve...we're just dealing with an unusual car here :paranoid:

You should have been around when I was wiring up the electronic ignition. I was looking around for a ballast resistor that wasn't there, then a black/white wire that should have had 12v but didn't, and then there was the black/yellow wire that shouldn't have been there but was...and had 12v. Not to mention pulling my hair out trying to figure out why something so simple that it only needed one 12v wire to work wasn't working.

I still don't know how the resistor was bypassed to get 12v in on and run.

That's a cool looking tool there but I just blew this month's car money on Weber carb kits

I'm going to have my hands full and my brain taxed trying to rebuild those carbs and get them adjusted while trying to get the ignition timing right too.