50 minutes ago, nowak1981 said:

That tells me that signal is getting all the way to the injectors and the only other item left in the line is the injector itself. At least on 5 cylinders anyway.

The injectors should always have power. The ECU closes the circuit allowing current to flow, opening the injectors. Your test was a good one for the injectors but doesn't tell you if the ground circuit back to the ECU is intact.

The tests from the EFI Bible do that.

Edited June 13Jun 13 by Zed Head

That satisfies me on the resistor banks. Just very odd that 3 injectors on one circuit are dead. Stranger things have happened I guess.

Hi nowak1981

I have a set of used/previously running injectors from my '76, resistor packs in case you need those too. You can DM if you are interested. I converted mine to the microsquirt setup with EV6 style Bosch ones.

Regards,
Den

@darom I caved and bought some amazon injectors.

The new injectors didnt come with the some of the o-rings and mine are too dried out to reuse. so im waiting on a set from zcardepot.

Can someone tell me if the intake has built in rubber for the injector ports? I pulled one of the rubbers out and it doesnt look like an o-ring, its squared off, almost molded to the intake. Im wondering if it is just the 50year old o ring thats been smashed into its new form.

You can see the parts here: https://www.carpartsmanual.com/datsun/Z-1969-1978/engine-280z/e-f-i/fuel-(to-jul-76)

It's a square shape by design. The small one is a seal, and there's a bigger one that is an insulator, probably meant for vibration and heat.

You can probably get them at your local auto parts store. The small one is very important, since it's an intake system seal.

p.s. amateur tip: it's tempting to try to assemble the rail and injectors as a unit then slip the whole thing in/on to the intake manifold. But it's actually easier to install the injectors first and slip the rail in to the hoses.

https://www.oreillyauto.com/shop/b/fuel-delivery/fuel-injection/fuel-injector-seal-o-ring-kit/ee721b9bfdb5/v/a/6637/automotive-car-1978-nissan-280z

Edited June 17Jun 17 by Zed Head

That’s good, the pictures on zcardepot are terrible, I wasn’t sure if I was getting a normal o ring or not.

Good news and Bad news.....

Good news is that I replaced all of my fuel injector connectors and they all work!

Bad news is that none of my new amazon injectors that were suggested earlier wont fire.

I tested all the new connectors with a noid light and they all work.

I also reconnected one of the old known working injectors and I could feel it ticking in my hand. I used this same injector to test the other connectors just to confirm what the noid light was telling me.

I pulled one of the new injectors and held it in my hand while trying to fire the engine and I could feel nothing.

These were the injectors I got

https://www.amazon.com/dp/B0FSQG62LD?ref=ppx_yo2ov_dt_b_fed_asin_title&th=1

On a side note, Why do half my injectors have the plastic spacer piece and the other half is one piece aluminum?

Over on another ZCar site we have seen the "no injectors firing after replacing all injectors with new" issue with some of the aftermarket injectors that are on the market today. One interesting this is that the injectors would fire if one or two of the injectors were disconnected. Even some of the Z CAR DEPOT injectors were doing it. Never could narrow down exactly what the issue was/is.

Someone that has way more electronic knowledge that I thinks it has to do with the inductance. Here is a link to that post

https://www.zcar.com/threads/1983-280zx-with-weird-injector-problem.427586/?post_id=2820006#post-2820006

I remember that thread from the other forum: https://www.zcar.com/threads/1983-280zx-with-weird-injector-problem.427586/ I watched that thread as it developed, but never got involved. I'm not sure I agree with their conclusions, but I certainly cannot disagree with their results.

In that thread, they noticed that if they disconnected one (or sometimes maybe two?) injectors, the remaining injectors would fire. Did you have that same result?

Or do yours never work?

Are your new injectors low or high impedance? Have you checked your injectors' resistance? If only half of injectors are firing, is it possible your dropping resistance pack is not working?

9 hours ago, nowak1981 said:

Good news is that I replaced all of my fuel injector connectors and they all work!

Bad news is that none of my new amazon injectors that were suggested earlier wont fire.

I tested all the new connectors with a noid light and they all work.

9 hours ago, nowak1981 said:

I pulled one of the new injectors and held it in my hand while trying to fire the engine and I could feel nothing.

When you say "wont fire" do you mean that you had fuel connected and they don't squirt, or the engine won't start? Or are you just going by feel in your hand?

Injectors don't really "fire" so it's not clear what you're describing. But, if the original problem was the electrical connections you should be able to reinstall the old injectors. They might be better than the new ones anyway if they're Nissan originals.

Edited June 21Jun 21 by Zed Head