im new here and have been reading other forms to try and fix my problem but nothing has worked so far... this is what i have and what i have done any help is much appreciated

i have a 92 firebird 5.0 tbi my injectors stopped working after i replaced my fuel pump.. thinking that it was odd that both my injectors went at the same time i replaced them anyways but that didn't work so i started replacing everything in the fuel system with new pump, regulator, filter and injectors nothing has worked so i started testing the electrical aspects and my fuel pump relay works the injectors are sending the pulse to the ecm the injectors are getting power the engine will start if i dump gas into the throttle body the injectors just plain wont inject idk what else to try any help like i said is much appreciated

 

What is your fuel pressure?

First Guess: The injectors work just fine. There's no fuel supply to them, so they don't squirt fuel.

 

13 lb sorry i forgot to mention that the proper pressure is their they are getting fuel all the way into the injectors i have taken them in and out multiple times and you can see fuel in the screens on both sides

 

also i have just rebuilt the engine a short time ago i put a new crankshaft and other internal parts its basically a new engine at this point i had it running fine until i changed the fuel pump which was disconnecting the pigtail and pulling the Assembly out after that the injectors just stopped working and from their i started changing everything is their something that i might have messed up in the three electrical lines in the fuel tank that would make the injectors stop working?

 

Fixed it for you. Punctuation and word choice makes your concept more readable and understandable.

I cannot think of any way that changing the fuel pump can disable the injectors EXCEPT that the new pump was defective or wasn't installed correctly, and no longer provides fuel volume or pressure.

Do the injectors click when someone cranks the engine? I'd expect that if you had a helper crank the engine, and you put a finger on each injector, you'd feel them pulse. I can't say I've ever tried this...but it should work to diagnose whether the injectors are getting the ground from the ECM to trigger them.

If the injectors pulse, but no fuel sprays out, and this happened immediately after you installed a fuel pump, I have to think the pump isn't supplying fuel.

Did you test fuel pressure AFTER you installed the pump? Have you ever tested the volume of fuel delivered?

Is there any gas in the gas tank?

 

sorry for punctuation. i will go now and see if they are clicking when the engine turns over. yes the tank has 5 gallons+ gas and when i was replacing the fuel pressure regulator their is enough fuel pressure to make it past the regulator so i didn't think that the pressure was the problem. also the fuel pump is doing what its supposed to as far as i can tell it hums when i turn the key. that's where my problem was i didnt understand why the injectors would just stop working after i replaced the pump.. also the throttle body has plenty of ground i just tested

 

periods are important.capital letters starting sentences not so much....

 

ok so i tried to feel for the injector to pulsate and couldn't feel it. they are sending the pulse for the ecm to read but it wasn't anything i could feel...

 

Capital letters at the beginning of a sentence, and spaces between sentences are second-grade concepts. It really isn't that difficult.

As I said, I have not tried this myself. I would expect the solenoid pulsing to be obvious...but I can't say for certain. Obviously, it would be more perceptible at the actual injector, rather than the injector housing of the throttle body.

The injectors don't send any pulse to be "read" by the ECM. The injectors are supplied with power when the ignition is turned on. The ECM controls the ground to cause current flow--and therefore a magnetic field--in the injector solenoid. As far as the injectors are concerned, there's no need for the throttle body to be grounded, because the ground is through the wire harness, at the ECM.

 

On my 93 s10 which was a 2.8l v6. It did the same thing. Ended up being a size 20 fuse called ECMB. It may be different for your car but it was a TBI set up just like my 91 Camaro RS 5.0l TBI. Check fuses first, if not fuses then check the connectors on the injectors, if those are good hook a wire to the terminals on the connector and push down on the injector while keeping the other side of the wire on the negative and positive side of the battery. Test this with the key on the on position, If the injector is good then it should spray a steady stream of gas into the throttle body. Try this for both injectors. Check fuel relays. As I said though on my s10 it was a fuse so that's as far as I got with testing my TBI on the old truck.

 

It sounds to me like it may be an electrical issue between the fuse box to the injector terminals, the ECM to the fuse box, or the ECM to the injector terminals. Get a hot wire voltage checker (not sure of the actual name for it) and go through all the wires you know that are hot. Even check the prongs on the inside of the terminals, the prong may be damaged or be corroded. If your terminals aren't getting power or enough power they may not let the injectors work. May want to check the terminal's ground wires too and see if there are still grounded correctly. I'm not an expert on electrical stuff or engines but I may be able to help since I did a lot of electrical work on my s10 so feel free to ask me something. If I can help I'll be happy too.