I need help! I bought a 91 camaro rs. Its a 305 tpi and it isn't firing the injectors. When I first got it it would only inject fuel when i was pushing down on the gas pedal, so I thought it was a fuel pressure problem. I replaced the fuel pump. Well, that just screwed me all up. After that the injectors wouldn't inject fuel into the engine. It is getting fuel all the way up to the injectors. Well, I thought maybe the injectors were bad, so I got new. But I actually got a whole new throttle body with injectors and a pressure regulator included. Well, still no firing on the fuel injectors. Any help?

I'm a handy mechanic, but only ever worked with carbs, first tpi I ever worked on.

 

did you check the injector fuse/s? pick up a noid light and see if they are being told to fire.

 

When the ignition is on they get power to one wire on each side. Should it pulse when I am cranking the engine?

 

Yes, I checked the fuses under the driver dash. they are all good. Are there more fuses other places?

 

im not sure on the 91 but there should be a fuse box under the hood.

 

I don't see one. Just the fuel pump relay. There is no actual box. Just under the dash inside the car.

I did find something interesting. The car doesn't have the original filler tube on the gas tank. It is replaced with a rubber connector so it can flex... that wouldn't cause a drop in pressure would it? It is sealed with hose clamps and doesn't leak.

 

i dont think so, pick up a noid light for your injector plugs at the parts store. its liek 25 bucks for a set and if you can find a individual one they are about 6 bucks. need to make sure the signal is not making it to the injectors.

 

Okay, I will check that tonight. Thanks.

 

When the key is in the ON position 12 Volt power to the injectors is provided by two 10 Amp fuses (INJ 1 & INJ 2) in the instrument panel fuse box. Each fuse provides power to one bank of injectors. All 4 injectors on one bank are ganged together with power on the PNK/BLK wire to the injector. The other side of each injector is connected to the PCM. Bank #2 uses Dark Green wires to the PCM, bank # 1 uses Dark Blue wires to the PCM. This engine batch fires the injectors (all injectors in one bank are fired simultaneously , alternately with the other bank. To fire the injectors, the PCM applies ground to the injector wire, which completes the circuit through the injector solenoid and pulls the injector open.

Before throwing more parts at the problem, get a fuel pressure gage and properly test the fuel pressure, the as others said, get a set of NOID lamps and see if the PCM is actually firing the injectors.
Pushing down on the gas pedal does not affect how much fuel the injectors deliver. The amount of fuel delivered is controlled by the PCM depending on the load on the engine.

 

The RS 305 didn't come with TPI, only a TBI unit (looks like a glorified carburetor). Which do you have? If you have a TPI setup, then somebody converted it, and a stock fuel pump for an RS TBI won't be putting out enough pressure.