Fuel pump and Relay problem

[brae]

I'm having a problem with my 1976 280z. The fuel pump works when I connect a battery to it, and I've checked for continuity on the relay and thats fine aswell, but when I dont have a dedicated 12v, it wont work.

When I try to start the car, it cranks but there is no click from the relay, and the fuel pump doesnt make a sound.

I've tried using the fuel injection bible for this problem (the relay not clicking). When I perform the continuity check for the 2nd step on page 55, I ONLY get continuity when the NEGATIVE is connected to 20 on the control unit and the positive is grounded. After performing this step I tried the one on page 56 but could not get continuity either way. I've checked the fuel pump/wiring/air regulator, and they all seem fine.

Also when I used a battery for the fuel pump while cranking, it still wouldnt start but fuel was going past the filter. Does anyone know how I can fix this, or if me putting a switch to bypass the relay to make a fuel pump switch would solve the problem I'm having? Thanks in advance.

[dexter72]

You may have two problems then. The injectors may not be firing either if you hotwired the pump and tried to start it. Check all your efi relays to.

[NewZed]

I have a 76 and all I can hear when I hit Start is the starter turning and the engine cranking over. Too noisy to hear relays clicking and the fuel pump running.

 

Try removing the small wire from the starter solenoid (it just pulls off) and then turn the key to Start. This should power up everything except the starter motor. Then engine won't turn over so you can more easily tell what's happening. It's a good way to test the fuel pressure also.

 

You're better off to use the 1976 FSM, Engine Fuel section, for your testing also, the "Bible" is somewhat generic and might miss the tests specific to the 1976 car. http://www.xenons30.com/reference.html

[brae]

I checked continuity on the air regulator and have found that the wire #48, from regulator to relay has no continuity. what should i do now? would that be the reason i cant hear the relay click or get the fuel pump to work?

 

Edit: Also checked AFM input and output to fuel pump and i have continuity in both. For the 1 3b test i had about 185 ohms then whenever i pushed the flap open it would get higher, shouldn't it be getting a lower reading?

Edit2: I have a few wires that i have no clue where they go (about 3), perhaps they could be another reason but they did not seem to fit anywhere, other then the black one on the afm that is under the top left bolt, but i dont know where i connect the other part of it to. I'll take pics tomorrow

Edited September 3, 2011 by brae

[brae]

So I did every test under the No start category of the FSM, including the voltage checks and what i've found is this.

1(6) water temperature sensor (13-ground) has no continuity

1(8) Air regulator and fuel pump (34-ground) has no continuity

2(2) Power line circuit is (10-ground) is only reading .04 volts

2(3) injector and dropping resistor terminal steps

A(cylinder 4, 14-ground),

B(cylinder 1, 15-ground),

C(cylinder 5, 30-ground),

D(cylinder 6, 31-ground),

E(cylinder 3, 32-ground),

F(cylinder 2, 33-ground) all are reading .04 volts

3(2) Air regulator - It didn't say to do this one, but it was only reading .05 volts at "start"

The line before the relay, after air regulator is the one that is the problem from what i can tell from the checks for the fuel pump not working, what should I do now, follow that wire and change it out? Lost please give tips.