78 280Z - no injector pulse

[kelley0352@att.net]

Am I wasting my time here??? several days ago I asked if anyone knows what is triggering the injectors. I have replaced ECU, Drop Resistor, Coil, pickup eye in the Dist.I have also replaced the transistor ignition module. I have power to the #1 pin on the ECU and all power where it is suppose to be & continuity checked all the ground wires. Also swapped out the thermo time switch and ohm tested all points of interest. The car has a new engine that ran for 4 minutes then died not to restart. I have fuel, spark,(at the coil & plugs) all new..;. 12v @ injectors but no noid light flickering so it won't fire up. 12v from a good battery to ignition switch , then to the ECU, then to the Drop resistor & coil. so why no noid light?

[kelley0352@att.net]

Sorry! PS;The car is a Datsun 1978 280Z all the injector systems are roughly the same. L28 engine

[EuroDat]

Hi Kelly,

I mentioned going through the tests in the EFI book. The one I linked you in the pm conversation. Have you done these tests? Could you share the results? It would help a lot if we have the information to go on.

[Captain Obvious]

And I would suggest that investigation be done outside of PM conversations. Investigations like this benefit other users in the future who are looking for solutions to similar problems.

[Zed Head]

8 hours ago, kelley0352@att.net said:

Am I wasting my time here??? several days ago I asked if anyone knows what is triggering the injectors.

The answer might be yes, because you don't seem to be reading the responses and trying what is suggested, or responding with the results.  My posted picture above, from June 26th, very clearly shows where Pin 1 is, there's a little arrow pointing at it.  You never replied back with what you found, until just now.

The injectors are opened when the ignition coil discharges.  The coil discharge is "seen" by the ECU through the voltage pulse on Pin 1.  If you don't have spark you won't get injection.

It might also be that your noid light is connected incorrectly.  That's not uncommon.  And, as has been posted before, some noid lights aren't fast enough or bright enough to see the flash from the injector circuit flow.  It's milliseconds long.

Are you sure that you have power to the injectors themselves?   "all power where it is suppose(d) to be" might not cover that.  Good luck.  Post the results of your work.

 

[Zed Head]

On 8/28/2014 at 4:08 PM, Virto said:

Mmk, minor update - the car has spark for sure - it'll run on starter fluid, there's just no fuel coming in since the injectors aren't firing.

Does it still start with starter fluid?  It's not uncommon to break one thing while trying to fix another.  Always good to reconfirm things that worked as you're working on a problem.

p.s. there is a way to trigger the injectors using a jumper wire at the ECU connector.  It's one way to confirm the circuit and the power supply, all the way to the ECU.  You can hear them click.

Edited July 18, 2020 by Zed Head

[kelley0352@att.net]

Sorry! PS;The car is a Datsun 1978 280Z all the injector systems are roughly the same. L28 engine 

Yes, I have ohm metered everything I could find and tested wire continuity. Removed & cleaned wire plugs ect. What really blows my mind is when I touched a test light,(with no voltage) to the posts on the coil to tripple check for juice on my running Z car....that knocked out the noid light signal to my injectors on this car too.!!!

[Zed Head]

5 minutes ago, kelley0352@att.net said:

Yes, I have ohm metered everything I could find and tested wire continuity

This is not how you check for power.  It's looking more and more like you don't have power to the injectors.  Get a VOLT meter and measure voltage at an injector plug, with the key on.

[kelley0352@att.net]

47 minutes ago, Zed Head said:

The answer might be yes, because you don't seem to be reading the responses and trying what is suggested, or responding with the results.  My posted picture above, from June 26th, very clearly shows where Pin 1 is, there's a little arrow pointing at it.  You never replied back with what you found, until just now.

The injectors are opened when the ignition coil discharges.  The coil discharge is "seen" by the ECU through the voltage pulse on Pin 1.  If you don't have spark you won't get injection.

It might also be that your noid light is connected incorrectly.  That's not uncommon.  And, as has been posted before, some noid lights aren't fast enough or bright enough to see the flash from the injector circuit flow.  It's milliseconds long.

Are you sure that you have power to the injectors themselves?   "all power where it is suppose(d) to be" might not cover that.  Good luck.  Post the results of your work.

 

Yes, I have power to the injectors, the #1 pin has power to it, I tested the drop resistor and it is all good, I checked the noid light on a running Z and the light blinks perfectly like it is suppose to

[kelley0352@att.net]

6 minutes ago, Zed Head said:

This is not how you check for power.  It's looking more and more like you don't have power to the injectors.  Get a VOLT meter and measure voltage at an injector plug, with the key on.

they are all @ 6.2-6.3 with a volt meter & with a 12v test light

[Zed Head]

If you take a wire and ground pins 14, 15, 30, 31, 32, or 33,  with the key on, you should hear the injectors click.  At least you'll know that most of the circuit and power supply is complete.  Use your noid light and you can avoid accidental short circuits.  Plus you'll see the light flash as the injector clicks.

[Zed Head]

6 minutes ago, kelley0352@att.net said:

they are all @ 6.2-6.3 with a volt meter & with a 12v test light

That is low.  Not sure how you're using both a meter and a test light.  Should be 12 volts on each pin at an injector plug it you measure them one at a time, using just a volt-meter.