Hey guys, I recently replaced my cam phasers and upon putting the engine back together (5.4 3v) the truck will crank but wont spark! I've narrowed it down to having potentially weak spark and no injector pulse. The truck will almost start with starting fluid, but not quite. The ignition coils are reading at 12v correctly but the other side is only reading at 250 millivolts... Does anyone know what the reading should be or if that is correct? The PATS system checked out fine and so did the fuel pump and fuel control module as well as the intertia switch and fuses. I've already replaced my crankshaft position sensor and both camshaft position sensors were recently replaced along with VCT solenoids. It almost seems as if it's a problem with the PCM not sending enough signal to the ignition coils to get it fully firing. I'm not sure where to go from here as i've had a tech come to my house and check it out and i've spent numerous days researching this problem. Would anyone be able to shed any light? I would appreciate any help!

 

since it happened right after the cam phaser change........ I would question the cam chain timing ... one bank 1 tooth off ? Im assuming you had the chains off and looked at the tensioners.

 

I don't believe that would completely keep the engine from starting would it? I had all the chains lined up with the marks so I don't see how it would be out of time anyway. Thanks for the reply though!

 

+1, what steve(ill) said.

 

sons 2006 EXP had cam phaser problem and I BELIEVE one chain jumped one tooth... and it would not start.


anything is possible...... but it happened RIGHT AFTER the chain / phaser work so that is suspect.

 

It almost tries to start!.
.
It's not a spark or fuei injection failure if that is what you see.
The computer only supplies ground and 'removes it' to the coils in the fire order and applies ground to the injectors in the same fire order but off set in time, since 12 volts is already standing on both the coils and injectors from a common fused feed.
Good luck.

 

Hate to ask but are sure on the timing? Did you take off the front cover or use a chain wedge yo lock both half in place then mark phasers and chain for realignment. I'm having similar issue with a 5.4.but in my case I have a no crank issue too

 

Just for kicks did you try resetting the pcm to read the new sensors?

 

X2. It ran before...after you put cam p hasers in it doesn't run.....Yep timing is off.

 

 

that timing mark on the drivers side cam, sure looks like a **** poor location... should have setup vertical or horizontal mark !

 

Just curious. Would a quick compression check verify there is a timing issue? Not sure about that that is why I'm asking.