I am working on a 98 Olds Bravada 4.3L Vortec VIN: W 4X4. I have spark, fuel pressure, injector pulse, and B+ to the injectors. I can get the injectors to fire if I give them direct power and ground. The plenum is removed and I have the fuel lines connected. The only thing I can think of is I'm not getting enough amperage through the injectors to open them or I have a connector problem, but I would think I would have an occasional successful injector spray if it was a connector issue. I've also been thinking a possible computer ground issue, however I have no other erratic conditions or readings from the scanner I'm using.

I've searched the forum via "search" and haven't found anything other than the connector issue, which could cause high resistance or no connection. I thank you in advance for any help.

PS I'm new to the forum.

 

What is your fuel pressure? It takes 55-60psi to open the poppet nozzles on the ends of the lines coming off the main injector body (commonly referred to as the spider).

How have you checked for injector pulse?

 

Yeh, like I said before I have injector pulse and if I apply battery power to one side and ground to the other I can get a single injector to spray fuel. Of course this is one at a time bypassing the pcm.

 

Well I checked my pcm grounds today and both grounds tested good. The only thing I can think of is the computer needs replaced. Im guessing that amperage if good since its good enough to light my test light. If anyone hase additional thoughts I'd appriciate it.