Chevrolet Repair: fuel injection, fuel pressure gauge, fuel pressure regulator

Question
I have a 1987 suburban R20 5.7L tbi I an not geting any fuel flow from the injectors the fuel pump is working fine fuel is reaching the tbi.If you poor fuel into the tbi the engine will start and run until the fuel is burned off.but there is no fuel flow from the injectors.i have replaced the fuel pressure regulator in the tbi that did not help.

Answer
It's possible that you may not have enough fuel pressure. You'll need to use a fuel pressure gauge to determine if your getting the proper 9-13 psi. If fuel pressure is ok the next step would be to determine if you're getting a pulse width circuit to the injectors. You need to unplug both fuel injector connectors and install an injector tester node light. With the engine cranking the node light should flash off and on. Do this on both fuel injector connectors. You can use a 12v test light if you do not have a node light but the flashing will be very dim.

If you're are getting a good flashing node light at both injectors, the injectors are defective. It's pretty rare that both injectors would fail at the same time thou.

If you DO NOT get a flashing light from your node tester it could be a fuse, open in the circuit to the injectors, distributor problem - pick-up coil, or defective ECM. You should have a service repair manual to get into this part of the repair.