No-Start: Fuel Injectors Not Firing 1978 280z

[rossiz]

...As for a source for a replacement plug, you should try Vintage Connections, they have a bunch of that stuff.

thanks for this link - i've been looking for this stuff for a while, looks like they have it all!

[Sideways78]

Ok so similar problem with not firing on my original ecu, injectors 1, 2, and 3 had no pop so except for higher rpms since my tach doesn't work I have to assume around 4-5k. Stripped that side of the harness, ran it along the firewall and rewrapped it replace all the connectors and injectors due to corrosion and brittleness, and replaced the ecu as well. Now I'm getting no start at all, power to the drop resistors, ecu, and coil. The timing seems to be working properly however I'm going to be going back over everything I've done on the harness after I use the original ecu to test it. I may have missed something when I was rewiring the harness. I updated all the components using 94 villager relay and fusible links, and a 91 sunbirds fusebox. I'll be posting again sometime tomorrow.

[Zed Head]

18 minutes ago, Sideways78 said:

Now I'm getting no start at all, power to the drop resistors, ecu, and coil. The timing seems to be working properly

Is there supposed to be a "no" in front of power?  No power to the dropping resistors, etc?  Or are you saying that you have power there but it doesn't start?

You know the timing is right because you used starting fluid?

Sorry.  All I see is "won't start, fuel injectors not firing".

[Sideways78]

That's the basic problem. I thought when I originally check the voltage on the connectors since there was power on both sides of 1, 2, and 3 (4, 5, and 6 worked fine) that something was wrong with the grounds but since they're all grounded through the ecu it had to be a problem with the ecu. Now I still have power to all components but the injectors aren't opening and I've read a little more about having the voltage on both sides I need to do some hunting. The main concern I have is that I've made a mistake with the harness I put together. Slowly giving myself a headache trying to trace it in my head. So tomorrow I'm putting the original ecu back in and trying a test run to see if I get the same results. 

Edited January 29, 2018 by Sideways78

[Zed Head]

You'll only have power on both sides of the injector connectors if the other injectors are still connected when you measure one.  If you disconnect them all and check for power you'll only see it on one pin.  When the other injectors are plugged in power comes back through the ground point at the ECU through the wire to the other pin in the connector that you're measuring.  It makes more sense if you draw it out.  It's a parallel circuit.

If you want to simplify things, disconnect all of the injectors and check for power at one pin on each injector plug.  Then plug them all back in and check for power at the ECU connector, for each injector.  You can remove all of the odd readings and parallel circuit back-feeding that way.  Then you'l know.

 

[Sideways78]

You know, I should've thought about it feeding through the ecu to the other injectors, that makes sense now. However I don't think I'll have to check the ecu connector for continuity if I am getting backfeed through each injector connector. Guess that narrows it down a bit. I'm gonna have to go back over my diagram and retrace the ecu's connections