Do you still have the plug wires running from left to right bank ? If so you might have one wrong..

Didn't you have the heads off ? Did you install the Timing chain right , Could there be a valve not closing because it's too tight ? The only time I've ever seen a V`8 backfire bad enough to catch the air filter on fire , the timing was off..
The good news is , you're getting fire and fuel..If not it wouldn't be catching on fire.

 

I can't Edit last post , Scratch Everything except the timing .. I would check anything and everything that has to do with the Timing ..

 

make since to me

 

How would I adjust the timing on a distributerless engine? I took the valve covers off but never the heads. I also thought that hemis where ohv engines so they wouldn't have a timing chain. I think I am not getting enough fuel either through having a worn out fuel pump or having dirty injectors. But hey I have been wrong before.

 

That's the easiest fix , Try it. If it don't work ?? I don't know..
But here's what I would do >
The Hemi is a ohv Motor. The Timing chain is behind the water pump under the Timing chain cover. It's not a 5 minute job changing it..They wear out and will slip when an engine don't act right. I wouldn't mess with any of that now , "But I would" get a list of every sensor on that motor that can affect the timing and change them. Cam Pos. Sensor etc..Make sure my knock sensors are installed and not damaged ..Not the sensors in the PDC~ the ones on the Motor... Take the fuel filter off , then turn the key switch on, it should shoot gas ..
If it don't then change the fuel pump ,
Did you adjust the pushrods , change valve springs , or anything like that when you had the valve covers off ? If not , No worries there..

 

I changed my valve springs. But I left the heads on. I am going to check my crank shaft position sensor. to see if it is working if it is I will replace it. hopefully that works. I have fuel pressure so if the crank position sensor doesn't fix it then I will need to check my injectors.

 

sounds like a plan. don't let it beat you

 

Are you sure you didn't over~tighten one of the valve springs , Or leave one too loose..An intake valve that won't close will make the ignited fuel come back out through the throttle body "Backfire"..
You're getting fuel , and spark , there's nothing left but valves and timing ..
Let us know what happens with the cam position sensor ..
BTW~Who tightened and adjusted the valve springs when you changed them ?

 

I did the valve spring job myself. I didn't k now that they needed to be tightened or adjusted. I just popped the old ones out put the new ones in and buttoned her back up. I will check my Haynes manual but i'm pretty sure it didn't say anything about adjustments.

Tomorrow is my day off so hopefully I get a chance to work on my truck.

 

In deed my friend . there is a special way to do any valve spring or valve job..When tightening the springs down you have to make sure it's in the closed position, and adjust them to the specks for that cylinder..It's very important to get them right or , uh-oh Hot dog..
mad~tv version of truck go boom...