Can I use a test light to check for pulse on the connector for the fuel injection? 1999 4.3 Cranks but no start.

 

A regular incandescent bulb can take too long to illuminate given a typical injector pulse, measured in milliseconds. LED's are best, but with LEDs, you have to be mindful of polarity (+ & - side of the LED connected appropriately to the injector wires).

It is quite rare to have an actual electronic injector problem with these trucks. What is much more common is fuel pressure issues. Check out the Tech Article (DIY) link found in my signature below and look for the no-start ignition system tests as well as the fuel pressure diagnosis thread.

 

A $2 mechanics stethoscope will tell you.

You can compare the noise it makes when you touch the rod against the injector body's.

You can hear the clicks from it spraying really easy, it's not perfect but can rule out alot quickly.

 

Problem with that theory is that the CPFI on these vehicles is squeezed between the upper and lower intake. And if it's older than 2003 IIRC it has poppet valves on the ends instead of electronic injectors.

 

Forgot about the chicken crap CPFI systems. But on standard per cylinder motors or tbi that works perfectly.

 

Yes sir it does. Just one more thing that is slightly more difficult about the 4.3 than it needs to be lol