the clicking I have always heard was either the lift pump humming or the grid heater relays.

it would make sence that the 1 and 5 injectors are fireing since the fireing order is 1-5-3-6-2-4 and when the engine doesnt see anything comeing from the CPS is just continues the 1-5 fireing untill it sees something from the CPS. when the engine is then turning and the CP3 is turning pressurizing the CR it continues the 1-5 and then sees input from the CPS and starts fireing the other injectors.


I guess if you didnt have this then an injector or two would be bad. but then the engine wouldnt run right

 

I am trying to determine if this is normal, or alot of trucks just have the same issue. Maybe different software. The clicking is loud enough that you don`t need to lift the hood. Just turn the key to run, and walk in front of the truck. If yours does it, you`ll know it. If there is a truck that doesn`t do it, than is that truck broke because its not clicking. I want to determine if it is correct or incorrect.

 

dodgeing the rain drops and lightning bolts curiosity got the better of me and I went out and set the ket to run. with the hood down I could bairley make out what I though was this rapid clicking, opened the hood and I heard it better. I unpluged #1& #2 injectors and the clicking in the front went away, but I could also hear the clicking in the rear. pluged the cable back up and the clicking started again.

I would have to say this is normal for the trruck to do this. my next concern would be does this cause the injectors to wear prematurely? I doubt it, but it is something to look into.