Fuel pump and Relay problem

[240260280z]

The 5th fusible link (For the EFI System) is at the +pos battery lead where it connects to the battery post. It can come unplugged easily.

It is labeled "EFI Power connector" by the fool who made this drawing:

Edited September 6, 2011 by Blue

[kenydat]

My dual relay(Fuel pump and EFI Relay) got messed up and cannot seem to find a replacement. I was looking for an alternative replacement and I came across this http://www.ratwell.com/technical/DoubleRelay.html.

Problem is I need to know the rating of the two diodes and the resistor.

Anyone with the ratings?

Thank you

[Zed Head]

Here is an expensive replacement - http://www.thezstore.com/page/TZS/PROD/11-3470

I don't think that the diode and resistor measurements are critical, from my limited understanding. They are there mainly to stop electrical spikes in the circuits when the contacts open and close (I believe it might be referred to as "flyback" - http://en.wikipedia.org/wiki/Flyback_diode)

Here's another link with some recommended diodes for a similar purpose - http://www.bcae1.com/relays.htm

More info - http://www.rvsafetysystems.com/Relay%20data%20sheet.pdf

If you're thinking about trying to make your own, you probably know this anyway, but just in case. Looks interesting, if you get it to work.

You might find a stock Datsun replacement on EBay also.

[kenydat]

Thank you Zed Head for the links. I have the engine running with two normal relays with one diode on the starter side. Problem is its running rich so I want to rule out the relay before i look into other components.

Will update you on the outcome.

[Brae]

I installed the injector connectors and no difference, but i took a look at that "5th" fusible link and i took pictures hoping it will help, im not sure which one it is because theres 2 wires that connect, but im guessing the one where the guy tried to tie it together with tape (its also very wobbly/loose; might be broke?) might be the reason for these problems im having. Just looking for some confirmation that it's the wire you are talking about. Would this alone cause the symptoms that i've listed?

[Zed Head]

You picture doesn't show where those wires connect. One of those red wires supplies your EFI harness (injectors ECU and relays), the other is a ground and connects to the negative post.

The one from the positive terminal should have a green fusible link. If you can't get a link, consider an inline fuse holder. The green link is estimated at 40 amps.

I would first determine which of those is the ground and which feeds the EFI harness, fix them up right,then continue testing. I don't think that you can test the circuits right until you get power to the relays.

Edited October 2, 2011 by Zed Head

[Brae]

The white wire connects to a fusible link then it goes to the relay on this pic. I dont see the other red wire on this diagram Edited October 2, 2011 by Brae

[Brae]

are you saying that my positive one having 3 wires coming out is wrong? Should i move the black one that turns to red with no fusible link on it to the negative side

[Zed Head]

I think, but am not sure, that one of those red wires is a dedicated ground wire for the EFI harness. The other is the power wire. If that is true, then you don't have a complete circuit for some of the components of the EFI harness.

I think that you can confirm which is which by finding one of the components that is fed by the white wire in your wiring diagram and testing continuity back to the one of the red wires.

But, yes, I think that you should have one red to positive and the other to negative. I just looked at my 76 to be sure. I wouldn't connect anything until I knew which red wire was which. From what I've read, it's not uncommon to be fooled by the red ground wire.

Edit - I just looked at Saridout's wiring harness diagram and the red ground wire is shown leading from the battery negative. It should be also connected to body ground so you should have had a direct short if you connected your battery cables with those wires connected like that. Unless it's already been damaged in the past. According to the diagram, the red ground wire also connects to Pins 16, 17 and 35 at the ECU connector, and one of the legs of the water temperature sensor circuit.

Don't guess and connect. My harness has some charred wires from POs' wiring work.

2nd Edit - actually it's shown in your copied wiring diagram also. A wire from the negative through a connector and on to 16, 17 and 35, etc. Both "R" for red.

Edited October 2, 2011 by Zed Head

[Brae]

ah ok, well the one with fusible link stays on positive, the other one ill take out and put it on the negative. Now it's starting to all make sense why lots of things arent working. since there was a direct short im assuming the fusible link is fried haha. I hope the other wire is fine.

[Brae]

i bought the car like this so when i plugged it in i never noticed anything weird, so it must of been fried before

[Brae]

so i changed the wire and fuse to an inline maxi fuse one, and these are my results for the FSM tests of the engine not starting. for continuity i wrote down the # and also set it to make noise if continuity existed.

1 (3a) AFM continuity from 6-8 181.6, no noise

( AFM continuity from 7-8 188.7, no noise

© AFM continuity from 8-9 101.5, no noise

1 (5) Fuel pump contact 10-20 004.2, noise

1 (6) Water temperature sensor 13-body no continuity

1 (7) Electronic fuel injection relay 20-body only made noise at "On"

1 (8) Air regulator and fuel pump 34-body only made noise at "Start"

1 (9a) Ground circuit 5-body 001.5, noise

( Ground circuit 16-body 000.7, noise

© Ground circuit 17-body 000.9, noise

(d) Ground circuit 35-body 000.8, noise

2(1) Revolution trigger signal 11.72 volts

2(2) Power line circuit 11.83 volts

2(3) Injector and dropping resister 11.81-11.83 volts for all 6 checks

3(1) Starter signal 11.64 volts

3(2) Air regulator 11.63 volts

3(3) Cold start valve and thermotime switch 11.74 volts

From what I see it seems that only 1(6) is the problem, but i could be wrong, am i reading this information incorrectly? please do let me know . on the + side, almost everything that was wrong with it before is fixed other than 1(6)

Edited October 3, 2011 by Brae