TBI wiring problems

[jswainthug]

I have had my motor all wired with all sensors getting the proper 5 volts. When i went to fire it up I am not getting any power to the injectors, also my fuel pump relay was working but now it will not send any power out (even with a new relay). I have tried to trouble shoot this all weekend. Any help is needed. Thanks

 

[mbryson]

I had something happen similarly when I was putting mine together. I just hard wired to the fuel pump as a test. Mine fired right up.

 

[jswainthug]

I did try that. My fuel pumps are working just no power to the actual injectors. I jumped a power and ground directly to the injectors and they worked great? I dont know I am lost!

 

[mbryson]

I did try that. My fuel pumps are working just no power to the actual injectors. I jumped a power and ground directly to the injectors and they worked great? I dont know I am lost!

The system is SUPER simple. I'd imagine you've got a blown fuse or something? There are two that control the ECM and the F/I. One is quite low amp if I remember right.

 

[jswainthug]

The system is SUPER simple. I'd imagine you've got a blown fuse or something? There are two that control the ECM and the F/I. One is quite low amp if I remember right.

It is not any fuse I have had a few problems with other wires in the harness having shorts, so I traced all those and got those fixed. I am basically wondering what powers the injectors, is it an alternative power source or does it come straight from the computer? I have no power readings anywhere along the injector lines. Would it be worth starting over? I really would rather not though!

 

[russelle]

jswainthug
The computer actually grounds the injectors to complete the circuit. They are wired hot via fuse, usually in the same circuit as the EGR/AIR wiring; assuming you are using a tailored GM ‘7747 harness. If memory serves me, the hot wire is pink w/ black stripe. PM if you need to troubleshoot.
Eric Russell

 

[jswainthug]

jswainthug
The computer actually grounds the injectors to complete the circuit. They are wired hot via fuse, usually in the same circuit as the EGR/AIR wiring; assuming you are using a tailored GM ‘7747 harness. If memory serves me, the hot wire is pink w/ black stripe. PM if you need to troubleshoot.
Eric Russell

Thanks man I may take you up on that, and you are correct about the pink with black, that is the power, I am so frustrated with this harness I may be starting over!