1976 280Z Wont Start

[NicholasKoenig]

Bought the starter fluid today and tried it out. The car cranked and would only run briefly on the fluid. The rail is getting fluid I can see it from the rail gauge.

I tested the injectors via the pins according to the efi bible. While testing each specific pin with key "on" I should be getting battey voltage. Which is over 12. 

But remember when I put the key "on" the voltage drops to 8 ish. And the injector pins via the in car harness read 8.55. So something is wrong there? 

Here's a photo of my dash gauge and you'll see the drop with just the key in the on position.

EDIT:

My fuel gauge doesn't work. It's not empty. I just put two more galons in today

 

Edited August 24, 2017 by NicholasKoenig

[NicholasKoenig]

After a bit more cranking and praying something new happened. 

No new starter fluid introduced but when I was cranking, every so often it would almost "catch" like the sound it would make right before starting up. 

I looked at my starter connections again. Where the battery positive wire goes to the starter and the other chassis power wire go. 

The bolt connection these wires to the starter is wrong and complete ate the ever loving crap out of the solenoid thread. Looks like that connection isn't secure enough to make proper contact and I can't tighten it down any more. 

A starter from rockauto is like 30$ and a solenoid is 25$. 

[JSM]

You should only have 3 volts or so to the injectors, if I recall correctly. That is what the dropping resistors are for.  Little silver metal box bolted to the fender side engine bay. I forget which side on the s30, left side on ZX. 

At least you got it to fire. I don't think the starter connection is causing your fuel issue if it runs on the fluid. 

[JSM]

1 hour ago, NicholasKoenig said:

No new starter fluid introduced but when I was cranking, every so often it would almost "catch" like the sound it would make right before starting up. 

The bolt connection these wires to the starter is wrong and complete ate the ever loving crap out of the solenoid thread. Looks like that connection isn't secure enough to make proper contact and I can't tighten it down any more. 

That is exactly how my ZX acted and then the injectors freed up.  Add some more starting fluid a few more times. 

Let it sit over night and try it again. 

I had the exact same problem with my starter too. Luckily I had a spare. 

Edited August 24, 2017 by JSM

[NicholasKoenig]

5 minutes ago, JSM said:

That is exactly how my ZX acted and then the injectors freed up.  Add some more starting fluid a few more times. 

Let it sit over night and try it again. 

I had the exact same problem with my starter too. Luckily I had a spare. 

Yeah it was like a fraction of a second away before fully awakening from its slumber haha. Ill let it sit overnight like you mentioned but Im searching for a new starter. Not that I think the starter or solenoid is faulty at this moment but the connection bolt in which the battery cable and chassis harness connect is FUBAR. Cant get the bolt tight, threads are beat so I fear this loose incomplete connection is/or can lead to an issue now or in the near future.

Also heres a screen cap of what I was following to test my injectors. According to the EFI bible my injector should read battery volts. But again, once I have the ignition "on", it drops to 8.5 and reads as such. Dunno how normal this is.

[JSM]

Yes it's normal. See the dropping resistors on the bottom of the page right above where it says notes. 

[Dave WM]

JSM I don't think he should see any drop with the engine on but not running the dropping resistors will only drop voltage in the presents of a load (injector firing). Unloaded there is no current flow, therefore no voltage drop across the resistor.

If you have 8.5v at the ECU there is a problem. Does your voltmeter on the car still read 8.5v? you need to find out whats going on. I check the battery AT THE TERMINALS, do this while cranking, should not be below 10v. When not cranking it should be over 12.5v

[JSM]

7 minutes ago, Dave WM said:

JSM I don't think he should see any drop with the engine on but not running the dropping resistors will only drop voltage in the presents of a load (injector firing). Unloaded there is no current flow, therefore no voltage drop across the resistor.

Dave I'm not following you. From how I thought this worked is the key switch supply's voltage to the dropping resistors which goes straight to the injectors. That's the positive side. The other 6 wires go to the Ecu which controls the grounding aspect of firing the injector. 

if that is not right please correct me. 

[Zed Head]

29 minutes ago, NicholasKoenig said:

Also heres a screen cap of what I was following to test my injectors. According to the EFI bible my injector should read battery volts. But again, once I have the ignition "on", it drops to 8.5 and reads as such. Dunno how normal this is.

Sounds like you have a short on the grounding side of the injectors.  The injectors are on two parallel circuits so one short could drop voltage on several pins at the ECU connector, I believe.  Could be a pinched wire in the injector harness or at an injector.  Check the wires from the ECU connector to each injector closely.  After you confirm that you have 12 volts available, as Dave suggests.  Measure each injector circuit and see if they all show the drop or just some of them.

If the threads are stripped on that starter lug try adding some washers under the nut to keep it on good threads.

Edited August 25, 2017 by Zed Head

[Dave WM]

the positive goes to the injector thru the resistors, but unless the other side of the injector (load in the circuit) is grounded thru the ECU power transistor, no current will flow. If you have an open circuit there will be NO voltage drop regardless of the resistor in the circuit. example you take a 9v battery put a 1K ohm resistor in series with it and read the voltage. there will be essential NO drop (still 9v) other than a tiny bit due to the load of the voltmeter (20meg) the 1000/20000000.

the dropping resistors act as a voltage divider only in series with the injectors.  

[Dave WM]

agree with Zed, assuming full battery voltage. you may even have smoked the ECU causing a leaking transistor, this would account for a voltage drop due to a partial on state.

[JSM]

1 minute ago, Dave WM said:

the positive goes to the injector thru the resistors, but unless the other side of the injector (load in the circuit) is grounded thru the ECU power transistor, no current will flow. If you have an open circuit there will be NO voltage drop regardless of the resistor in the circuit. example you take a 9v battery put a 1K ohm resistor in series with it and read the voltage. there will be essential NO drop (still 9v) other than a tiny bit due to the load of the voltmeter (20meg) the 1000/20000000.

the dropping resistors act as a voltage divider only in series with the injectors.  

Oh I gotcha. Thanks.