Electrical Problems 78 280z

[SteveJ]

5 hours ago, tleverett said:

Fuel pump relay. 90-91 did not have continuity in normal condition. 93-92 had continuity when +/- was added to 90-91
Fuel pump control relay under normal 95-91 yes. 95-94 no.

So it appears all 3 relays are bad. Fml any idea where is best to get them?
 

You have me at a disadvantage here. I do not have a 78 280Z, and the wiring diagram does not have pin numbers from the relay. Could you post a photo that shows the pin numbers so I can verify your findings?

[SteveJ]

I should add that the ignition relay is NLA. I have made replacements for people by utilizing conventional off-the-shelf relays.

[SteveJ]

I'm not sure if this works, but it comes up on Advance Auto's cross reference: https://shop.advanceautoparts.com/find/1978-nissan-280z-fuel-pump-relay.c7634

Z Car Source lists exchanges for the Fuel Pump Control and Fuel Pump relays. https://zcarsource.com/used-nissan-280z-fuel-pump-control-relay-for-the-1977-78-starting-in-august-of-1977-datsun-280z https://zcarsource.com/used-nissan-280z-fuel-pump-relay-for-the-1977-78-starting-in-august-of-1977-datsun-280z

[tleverett]

@SteveJ

[tleverett]

@StephenJ I'm sorry I'm unfamiliar with what NLA means. And honestly if you could do that it would be a big help.

I looked at the first one, its pins are set up differently on the picture. Is that just a random display image you think, or would i have to find a matching harness and rewire it? It seems z car source has it for $100, ouch.

And for the control relay just z car source them and ask right?

 

[Patcon]

NLA = No Longer Available

[tleverett]

@Patcon ahhh makes sense

[SteveJ]

18 hours ago, tleverett said:

Fuel pump relay. 90-91 did not have continuity in normal condition. 93-92 had continuity when +/- was added to 90-91
Fuel pump control relay under normal 95-91 yes. 95-94 no.

So it appears all 3 relays are bad. Fml any idea where is best to get them?
 

Okay, I looked in the FSM. I don't like how that test was written. (Mind you, I work on industrial control systems for paralleling generators, so I'm used to relay logic.)

1. 90-91 does NOT have continuity. It will have some resistance as you're reading through the coil.
2. If 93-92 had continuity when voltage was applied to 90-91, the relay is functioning as designed.
3. 94-95 does NOT have continuity. It will have some resistance as you're reading through the coil.

To elaborate on what I posted in the other thread, 94 is normally grounded at the alternator. 95 is positive from the ignition relay. 96 is grounded at the oil pressure switch. 91 goes to the fuel pump relay. 97 is positive only when the key is in the START position. The oil pressure switch is closed when there is no pressure. So in a "no oil pressure" situation, both coils in the relay are energized, and the fuel pump relay coil is energized if the car is starting. Once the car has started, the oil pressure switch opens up, and the fuel pump relay coil is energized from the ignition relay via the fuel pump control relay.

It would not surprise me if the ignition relay is the culprit here.

[tleverett]

@SteveJ that's interesting and helpful that you know this stuff. I was so confused because while there was no continuity on the fuel pump switch, it energized and had continuity on the other posts perfectly. I guess it doesn't make too much sense to check non energized continuity because there should be nothing that makes it bad, more so connections and switches are the part that mess up not energizing properly. Sorry if my wordage is bad. 
Would you still be able to help out making an ignition switch? I still need to check the energized fuel pump control relay because i stopped checking when it didn't have continuity in normal state. Also need to get gator clips because testing with just pins is extremely difficult and tedious lol. But considering i know that switch is bad might as well start somewhere.

[SteveJ]

Clip leads are easy to find: https://www.harborfreight.com/18-inch-low-voltage-multi-colored-test-leads-66717.html. Just drive over to Modesto.

As for the ignition relay, let me check my supplies and PM you.

[tleverett]

@SteveJThanks A bunch, I'm going to grab some leads on the way home from work and give the fuel pump control relay a shot! Let me know if I can help at all with the ignition relay.

[tleverett]

@SteveJFuel pump control relay

Normal:

95-91 yes

94-95 no (you said this shouldnt)

With current to 94&95: I can hear the relay actuate

95-91 yes

95-96 no but i believe the number shows resistance?

With current and ground:

97-96 no

95-96 no

The with current and ground i'm not sure if i did correctly, i tried touching to screw in lightswitch plate. I'm not sure if thats good enough