No injector pulse

1994 GMC SIERRA
169,000 MILES • 5.7L • V8 • 4WD • AUTOMATIC
Avatar
CARSDAVE84
  • MEMBER
  • 2 POSTS
No fuel being delivered to cylinders. Fuel system including throttle body has been replaced, noid light is not showing any pulse. Ignition module has been replaced as well. I am wondering what else I can check for. Fuses and relays are good as well.
Sep 24, 2018 at 1:38 PM
Advertisement
Avatar
ASEMASTER6371
  • ✓ASE Certified Mechanic
  • 52,796 POSTS
  • ASE Certified Mechanic
Good afternoon.

Do you have spark? For the injectors to fire, the ECM needs to see a crank signal or rpm reading.

Do you have power to the injectors? Fuse box feeds power to the injectors and the ECM quad drives ground the injector for fuel to flow.

I attached a diagram for you to view. Check the fuse listed for power on both sides.

Roy
Image (Click to enlarge)
Professional Diagram for 2CarPros Members
Click here to log in and view diagram.
Sep 24, 2018 at 2:16 PM
Avatar
CARSDAVE84
  • MEMBER
  • 2 POSTS
Thank you for the response. I checked the connections and fuse link with volt meter, I am getting good power on both sides. However, I am not getting spark as well.
Sep 24, 2018 at 4:27 PM
Avatar
ASEMASTER6371
  • ✓ASE Certified Mechanic
  • 52,796 POSTS
  • ASE Certified Mechanic
Okay, check the cap and rotor. Check you ignition module as well. Common failure for no spark.

Once you get spark, fuel should return.

Roy

https://www.2carpros.com/articles/how-to-test-an-ignition-system
Sep 24, 2018 at 4:33 PM
Join 2CarPros for free, one of the most advanced car repair communities on the internet. From first-time drivers to seasoned mechanics, everyone is welcome to reply, share details, and get better answers. You can add a temporary image or video first; uploads are limited to 20 MB.
Ask a Free Question
Repair Safety Notice: This information is for general instructional purposes only. Vehicle repair can be dangerous. Verify all information, follow manufacturer service procedures, use proper tools and safety equipment, and consult a qualified repair shop when needed.