Hey guys,

I am new to this forum and am finding that there is a wealth of knowledge here!
On that premises, here is my current situation:

-1983 280zx 2+2
-has not run in over 5 years
-last time I messed with it, the car would start up, run for 3-8 seconds and then quit.
-Now it will not fire up at all.

I had a friend who is a mechanic over yesterday to run some tests and see what could be the problem. He is indicating thru running a NOID test that the injectors are not receiving the correct signal to open, therefore the engine is not getting fuel. He cleaned many connections and checked fusable links. His thought is a bad ECM/ECU. He had indicated that it had been swapped out previously(thru the writing on the back of it)

I have two questions for now:
1. Is the green light on the ECU/ECM supposed to remain on at all times?
- it currently comes on for an instant when you turn on the key
2. Has anyone ever used the ECM/ECU from Advance auto, as they are indicating a good fit for this vehicle?

Any advice on moving forward would greatly be appreciated!

Thanks in advance,

Surfpilot

 

Welcome to ZDriver!

All the noid light does is test for a completed circuit when firing... it's a start, but really you just need to check if the hot side from the battery / fusible link actually has power. If the ecu green light is coming on, the ecu has power. Since the car at least started 5 years ago, the more likely scenarios:
-Fuel pump is toast (did your mechanic buddy check fuel pressure???)
-Gunk in the fuel lines
-Trying to start with old gas (hoping you flushed the tank... gas more than 2-3yrs old is slightly more ignitable than water).

Start with checking for power at the hot side to the injector wiring, check fuel pressure, and check for spark at all 6 plugs... we'll go to that point.

 

NismoPick,

Thanks for the quick response! I am really excited about trying to get this Z back on the road. (so are my young kids, who believe once the car is running again it will become theirs)

In my quest for knowledge, I believe that I have left out some important parts of my questions.

-What does the green light on the ECU/ECM supposed to do and when? Should this light say on the whole time? or should it be on during the ignition process? or just the very quick on then off that it is currently doing?

-The symptom I have is the injectors are not receiving signal to open. I am trying to find out about signal control going to the injectors. ( per my mechanic)

I have changed the fuel pump and will be draining the old gas out today. I will be trying all the points you have mentioned today("Start with checking for power at the hot side to the injector wiring, check fuel pressure, and check for spark at all 6 plugs... we'll go to that point.")

Thanks again for the helpful information and the welcoming to the website.

Surfpilot

 

The ECU green light does not always stay on. It flashes at various times depending on what's going on. There are various tests you can do and the ecu will respond with blinks... not a true "OBD diagnostics" like the Z31 or OBDII, but it helps you diagnose the O2 sensor and a few other things.

Make sure you download the FSM... all this info is there: XenonZcar.com S130 Factory Service manuals

 

Update:
In the effort of getting the fuel injectors to open we have found the wires
#34,#17,#5 are not grounded.

Does anyone happen to know know the location of these grounding points?

I thought I had read years ago that someone with the same problem had difficulty finding grounds in the 280zx or that when he did find the grounding point it was such a rusted area that he ran the ground to a different location.

I cannot not find that previous post with the information, so any ideas would be great!

Thanks for the help!

Surfpilot

 

I'm quite confused... Are you / is your mechanic using the FSM wiring diagrams? It seems that you are not.

83 N/A EFI:
#34: To AFM
#17: Direct battery power thru fusible link *NOT GROUND
#5: Ecu ground signal to injector 4.

Please make sure you've downloaded the FSM here: XenonZcar.com S130 Factory Service manuals

 

to confuse you further there is always a hot wire to the injector. grounding takes place thru the ECU at the proper time.