I have a 2003 Chevy Blazer LS that is having issues when starting. The issue goes as follows....

When going out to start it for the first time of the day, I turn the key over and it just cranks but does not start. I figured out you can get it started by turning the key off and on then letting it sit with the key in the on position for a bit until you hear the fuel pump kick in and run, and then it will start right up. It some times takes a few times of turning the key on and off to get it to go. I notice the battery voltage guage goes up slowly as well when waiting for pump to kick in. After getting it started once for the day it will continue to start fine the rest of the day. The issues seems worse when its extra cold outside. When this issue occurs the gas gauge will also drop to empty and then once the fuel pump kicks back in, it goes back to reading fine. I have swapped the fuel pump relay and replaced battery. Any input would be appreciated! Thanks!

 

Sounds like you have a partial or total system voltage problem at key on. The question is whether its the whole system voltage or just a section. We just keep splitting the problem in half until we have the problem. Get ready with your digital multimeter and as soon as you have a no start condition and the dash voltage gauge is low check:

1) Battery voltage at the battery terminals
2) Confirm low voltage at a cigarette lighter plug
3) Check the power in to the ECM B fuse 20A in the UHFB. This feeds the fuel pump relay

Depending on those answers we keep narrowing it down so report back.

It could be the ignition switch among other things and we may be under the dash soon enough but you can try this low tech hack and wiggle the switch in run mode and see if the voltage varies..


George