3406E won't fire up.

All the solenoid does is load the amount of fuel into the injector it does not fire the injector. The cam does. But you have to have enough fuel pressure to push into the barrel of injector to Pop it off. That is what the solenoid does. The injector body is moving all the time by the cam lobe. With or without fuel. If the solenoid fired the injector why would you need a cam for the injectors?

 

The solenoid does not in fact fire the injector but it allows fuel into the barrel. The solenoids are what lets the truck start and when you turn the key off they are what makes it stop because no fuel won't run. Used to be a solenoid on the pump now it's injector solenoids. Either way check the ecm and then fuel somethings wrong with one of the two.

 

like bangin my head against the wall. I'm done, good luck Luwi67.

 

Luwie67
Sorry I got these guys off on a complete different subject I should of started a new post
But I don't like to see unclear post

 

Super hauler and Cory wood are correct.

If you have air in the fuel system the injector won't build the required psi to pop off.
And yes the ecm energizes the selinoid on the injector to close the spill port. The fuel then gets pushed thru the tip into the engine instead of back into the fuel rail.
So yes the cam does not fire off the injector the ecm does.

 

You were right up until the last sentence. But you almost had it.

 

The ecm is the deciding factor in weather the injector fires or not . Also it is the deciding factor in how long that spill port stays closed.
The cam is a contributing part in firing the injector but it is not the deciding factor. Again the ecm is.

Not sure why you don't understand that.You seem like a smart guy in most of your posts.

 

This is going to sound weird, but those two little dime sized check valves in the primer pump base can somehow get flipped over. One of them allows fuel in from the transfer pump, but not out; the other allows fuel to flow toward the injection pump, but not back into the primer pump. The two of them together are what makes the primer pump work when you pull the plunger and then push it back in.
If either one of those little check valves flips over, it will not allow fuel to flow through.

I had a friend with a brand new truck (this was in 1990) with a 3406. He had only had it about two weeks, and it got to where he could not start it. I was with him where we were loading, and there was a Cat shop close by, so I pulled him to the shop with my tractor.

The mechanic scratched his head for a moment and was preparing to start checking fuel flow much as recommended in this thread, when he stopped and said "I'd better check the primer pump first". That was when I learned that these little check valves can get flipped upside down somehow.
Several years later, after I had forgotten all about this, my truck quit me in a fashion like it was running out of fuel, not all at once like you shut the key off. There I was along side the freeway in Southern Utah, changing fuel filters and checking tanks, when I remembered about the check valves in the primer pump. Sure enough, it had happened to me.
Since you did not have the primer pump on when this began, this surely did not contribute to the problem, but I just thought that I would mention it for general knowledge.