What are the facts about 280z ECU compatibility and differences

[Patcon]

What is the possibility of a neutral switch input for the auto ECU?

[Captain Obvious]

It sounds like your A11-600.... unit has a problem.

My first WAG would be a blown output transistor and you're running on three cylinders. You should be able to check those big TO-3 buggers in-situ. They're Darlingtons, but you should be able to check them with the ol' Simpson.

[Dave WM]

2 hours ago, Captain Obvious said:

It sounds like your A11-600.... unit has a problem.

My first WAG would be a blown output transistor and you're running on three cylinders. You should be able to check those big TO-3 buggers in-situ. They're Darlingtons, but you should be able to check them with the ol' Simpson.

has a schematic of those ever been found?

[Captain Obvious]

I've never seen a schematic for the entire ECU. I've reverse engineered a little bit of it (very little).

One of the sections I DID do however, is the output transistor section. Pretty self explanatory. I'll see if I can dig that up.

[Zed Head]

There's a reference to a Hybridz page in this thread that cygnusx1 supplied a while ago, that shows what some of the components do.  Not in schematic form, but better than nothing.  It's near the bottom of the Hybridz page.  The link still works!

 

[Captain Obvious]

And about that HybridZ page...

"If I remember correctly... The pics are wrong. The resistor designations are non-existent. And there's talk of a lamda sensor. All that spells different ECU."

[Zed Head]

It's just another reference point.

[Dave WM]

I really want to get a scope hooked up to the injector so I don't have to fiddle around with the stethoscope and listen for it. Think the process will be to leave the good ecu hooked up, run the scope and video capture that. Then install the bad ecu and scope again to see if there is anything going on up until I manually override the AFM flap. If I had been thinking I would have tried disconnecting the temp sensor just to see if that would have allowed the bad ecu to work (I know that is of little value as far as using it, but would be interesting to see the effect. besides in a road side emergency, it could be something to try, if the defect is overcome by that).

[Zed Head]

You can get the ECU to open the injectors just by triggering three sparks, with the key on.  If the circuit works.  You could probably build a testing device with just power to the ECU, some lights on the injector grounding transistors and a voltage pulse to Pin 1.  People often run their engines with the AFM unplugged.  The base pulse is very basic, apparently it doesn't really need any sensor data.  It's the starting point and all else is an addition to its length.

Just saying, it's a simple input-output device.  A scope would tell you base pulse length but might be more than needed to see if the ECU works or not.

[Zed Head]

The FSM implies that the AFM signal is necessary but it must not need to be generated by the AFM.  Since the engine will run with the AFM unplugged.  The ECU just uses whatever is on those wires at the ECU connector.  Open circuit seems to be enough.

[Zed Head]

The three spark test supplies higher voltage to the EFI system than using the starter.  Might be a clue.  Plus it's quieter.  Easier on the brain waves.

[Dave WM]

is that when I just make and break the pin 1 signal from the coil? so I do a make break 3 times and I should hear an injector click. Will give it a try with the working ecu, then again with the non working ecu.