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Jimmyb

Datsun 280zx won’t start

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9 hours ago, Mark Maras said:

 Kind of a shot in the dark but the fact that it will start but not run leaves me wondering if this could be ignition switch related. There was a thread just a few weeks back that described the same symptom. It's quite common for them to fail in this way.

Yep I said that earlier. 

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15 hours ago, Zed Head said:

 

That's a good one.  Jimmyb's noid light could be used to check for power at the coil with the key on.  That would answer that question.  Check for power at the coil with the key at Run/On, and at Start.

Edit (reread previous posts) - Not sure why the noid light was needed to check for injector power.  Just measure voltage with the meter.  Anyway, check the fusible links that supply power to the EFI system.  I don't see any actual voltage measurements in your testing.  The ignition system is on a completely separate circuit than the EFI system.  You can have spark and run it on ether, with no power to the EFI system.

image.png

1. The noid light was put into the injector connector because it should blink while I crank the engine right? It didn't.

2. We have measured battery voltage after after after all fusible links, and they are OK.

3. We recently tried grounding each injector with a wire from battery - to respective pin on the ECU wiring connector and all injectors opened. (For the first time while in the car i believe)

4. We also applied battery voltage to pin #13 and the fuel pump started. That's the first time the fuel pump started without direct voltage from a separate battery .

That tells me that the wiring + relays for the EFI and Fuel pump are OK? Am I wrong?

feels to me like we have ruled out the basics and there has to be the ECU or a grounding problem, if there's a grounding problem then it's NOT pin #18 or any of the pins to the injectors of the ECU.

 

So, on todays agenda.

Test the ignition switch. First with the noid light and if there's no power at the coil with the key at Run/On, and at Start, then try replacing the switch with a switch button and a push button.

But if it is the ignition switch, should'nt the car be able to fire up - then die without starter fluid? The EFI relay clicks when I turn the ignition on but the injectors won't fire when cranking the engine, as meantioned earlier they do fire when grounding respective pin from the ECU connector. Could this still have anything to do with the ignition switch? The switch do go through the EFI relay so maybe, but it still clicks. Well I'm just gonna try it out.

 

I found this image to use when connecting a button + a push button, seems about right yeah?

Thanks guys, you're awesome!

4973.jpg

Edited by Jimmyb
Missed a few things

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A test that might show you something would be to run a hot wire from the battery to the coil's positive terminal.  If it stays running when you use a hot wire then you can focus on losing the ignition system power.

You might also check for power on Pin 27 with the key on.  That's the power from the EFI relay to the ECU.  If you have power there you'll know the EFI relay is working. You mentioned the click, and the injectors opening but if you look at the diagram is shows that the injector power doesn't come through the relay, it has its own fusible link.  And the relay can click but still not pass power.  I'm not sure that the diagram is correct but it's worth a check of Pin 27.  The ECU needs power too.

Study the diagram and you'll find many small tests you can run for power and ground.  Once you don't find the big easy source of the problem you almost always have to work through the tedious small tests.  But when you find the one thing that's wrong it will be worth it.

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Forgot to say also, check the ground circuit for the ECU and EFI system.  There is a separate ground for the connector, you can see it at 19, 20 and 22.  People often get so focused on the power that they forget about the ground.  

Edit - the tests I described are all written up in the pages following the EFEC-80 diagram.  Your fuel pump power test above, usng Pin 13, kind of indicates that you're not going through the tests in the FSM.  There's a simpler fuel pump power test on page EFEC-94, using the starter solenoid wire.  The test we often recommend.

Sometimes, as you're learning these new things, it's a good idea to go back and re-run a series of tests.  They make more sense the 2nd and 3rd time around.

 

Edited by Zed Head

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I will replay to tips and questions later tonight, just have to post this images. So this is the ECU inside. Am I wrong or is the D251 and the one next to it burned. Also the ZD740 looks pretty bad. Are this ECU shut? And how can this happen?

IMG_20171119_1841182.jpg

IMG_20171119_1841337.jpg

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Connecting the battery backward can cause problems.  Short circuit somewhere in the wiring maybe.

Good find.  Bad news.  

I just noticed what you said earlier about trying a 1978 ECU.  1982 is completely different.  Nissan actually wrote some notes when they changed the ECU's saying "Do not try early ECU's on these cars!!!!"  So that was a bad idea.  Anyway, you need an ECU that's right for the car.  Here's a link to a guide with ECU numbers.  Maybe yours is not even right for the car.  Post up the number.

 

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49 minutes ago, Zed Head said:

Connecting the battery backward can cause problems.  Short circuit somewhere in the wiring maybe.

Good find.  Bad news.  

I just noticed what you said earlier about trying a 1978 ECU.  1982 is completely different.  Nissan actually wrote some notes when they changed the ECU's saying "Do not try early ECU's on these cars!!!!"  So that was a bad idea.  Anyway, you need an ECU that's right for the car.  Here's a link to a guide with ECU numbers.  Maybe yours is not even right for the car.  Post up the number.

 

 

47 minutes ago, Zed Head said:

Save you some time - 

image.png

Since we know have tried almost every pin from the ECU connector I really hope there's not the ones who are left that has caused this. The battery that was in the car had been there since -93 and was exploded etc. could that cause this? If someone tried to start the car with a broken battery? And no, it wasn't me, a bought a brand new battery the first thing I did.

I'm looking for a ECU as we speak, I know of a guy from Poland who deals with Datsun and Datsun parts that might have one for my car. 

Oh my.. Haha, did they say why I shouldn't try a earlier ECU? Nothing seemed to go crazy so let's hope it didn't.

What does the P-Part stands for? 22611 matches but not the latter.

IMG_20171119_1921246.jpg

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