Bringing a 1977 Z back life

[Zed Head]

9 minutes ago, Av8ferg said:

Okay, absorbing all the advice.  ZH, tested voltage to the battery fuse link and got 12.7v.  Fuel injection power relay tested good right out of the FSM.  The bad news is I cracked the board when crimping it back into the metal cover.  It’s still tests good but might need replacing now that I have compromised it.  

I’m going to find the power wire and see if Inget continuity now.  While rummaging around looking for wiring problems I found this on the passenger side above the fuse box.  Are these two barrel connecteors supposed to be connected to something?  

Finally can I test power to the injector plugs themselves.  I’ve read I should be getting 12v on them, but I’m getting nothing.  Disconnected the starter had my assistant turn key to the start position and then tested the  voltage from one pin of the injector connector and other to a ground.  Nothing....

Power to the injector plugs runs through the relay.  So if the relay is good and there's power to the relay plug you should have power at the injector plugs.  Only on one side though, if all of them are disconnected.  If they are connected then you might see power on both pins, through backfeeding from the other injectors.  You should see power when the key is at On.  You're testing the right way with one probe on ground and the other on the pin.

I'd probe all of the pins at the relay plug and see if there's power there with the key On.

 

[Zed Head]

Here's a wiring diagram.  Check your dropping resistors also.  That's where the power goes right after it leaves the relays.  You never what someone might have unplugged in the past.

[Av8ferg]

Tested both plugs that go to the Fuel Injection Power Relay.  Only one showed voltage and that was pin 70 which goes to the positive battery terminal thrrough the fuse link on the positive terminal.  I got 12.7v. No voltage on any other pin in the plugs.  

Where are the dropping regsistors located?

[Dave WM]

by the brake booster

[Zed Head]

25 minutes ago, Av8ferg said:

Tested both plugs that go to the Fuel Injection Power Relay.  Only one showed voltage and that was pin 70 which goes to the positive battery terminal thrrough the fuse link on the positive terminal.  I got 12.7v. No voltage on any other pin in the plugs.  

Is that with the key On?  That's a good test of your EFI fusible link.  You should have had power at 73 also.  I think that fusible link is the Ign fusible link.  It powers your ignition switch.  Looks like you either have no power to the switch or the to 73 is broken.  

Here's a link to a bigger diagram.  This progress, although it probably doesn't feel like it.  The diagram might be hard to follow.  But it shows that 73 gets its power through a path that goes through a couple of connectors, and also branches off to the ignition relay.  But it starts at the fusible link.  Might be that your Ign fusible link is blown and the source of many of your problems.

Recheck the fusible links. ( p.s. Even with carbs you need the Ign link ).

http://www.classiczcars.com/files/category/1-wiring-diagrams/

[Av8ferg]

ZH, with the ignition “ON” I get 12V on pins 70, 71 and 73,

[Av8ferg]

These links are all brand new. I also cleaned the terminals with a wire brush before installing.  

[Zed Head]

Those power readings are all correct.  Your wiring to the EFI relay looks right.  Should have power to the injector plugs with the key On.

Like Dave said the dropping resistors are in a pocket underneath the windshield washer bottle, by the brake system.  You'll have to remove the bottle to get in there.   They don't really go bad though.  Eyeball them and make sure they're plugged in.  OR unplug them and check for power.

Also, make sure that you had a good ground point when you were measuring power at the injector plug.  

And also, somebody (maybe it was you, I can't keep up) just had a problem with the ground on top of the intake manifold.  It wasn't good.  It's in one of your intake manifold pictures.

Edited February 22, 2018 by Zed Head

[Zed Head]

Make sure that this ground has low resistance to the battery's negative terminal.

[Av8ferg]

Yeah, those wire jobs on the grounds are on my fix it list   That was there when I got the car.  

[Dave WM]

good ground at 72? see if you get any voltage there with a test lamp or meter with it hook up to the relay and the switch in the "ON". reading from chassis to 72. If you have a good ground you should have 0 volts there (or better yet no light on a test light).

[Av8ferg]

Well, I think I’ve got another stopping point since I kinda trashed the Fuel Pump Injector Relay.  When I plugs the wires back in to relay the fuel pump started pumping with the key off and thats with the ECU disconnected. 

The dropping resistors looked fine.  Just looked like a couple connectors. They seemed properly attached.