General ECU injector not firing

[Cutty455]

Does the ECU affect fuel injector firing? Number 4 injector is not firing. I swapped injector spots still the same. I have even pulled the wires on each injector an 4 doesn't change in idle. Need help. I did just replace the ECU about 2 months ago. 90 laser turbo California car

 

[AWD-Tony]

So all injectors have 12v? Ecu controls the ground side so if it’s only injector 4, I’d check continuity at the #4 injector plug and pin 61.

http://www.dsmlink.com/images/forums/1GECUPinout.pdf

 

[Cutty455]

Just with a volt meter? How do I check the ECU pin? Kind of lost on all the electric testing

 

[AWD-Tony]

You can use a voltmeter.
First, make sure the black wire has constant 12v. Turn the key to on position and put one lead to the black wire and the other to ground.

If that’s good, take one lead to the colored wire and the other to battery + and crank the car. It should spike battery voltage for a second. This might be easier with a test light.

This should help

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