2002 explorer, 4.0 no start

[Rondak46]

hello. New to the forums. I am trying to help a neighbor get her car running. I don't know anything about explorers but I am familiar with Jeeps. Some things have been changed: MAF sensor and coil pack have been changed. The engine will turn over but make no attempt to start. I used starting fluid and the results are the same. I am seeing spark at the coil connectors and at the plug. The color of the spark is yellow. When it turns over I can hear a loud tick, more like a clank. I think it is a serious problem but I don't want to tell her it's done if it is not. I will try to upload the video. Any help is appreciated.

 

[Rondak46]

Here is a link to the video.

 

[plasticseng]

Can you tell a general vicinity for that knock/click sound?

 

[Rondak46]

Plasticseng, only very generally. It seems to be coming from the front of the block. It sounds internal.. Thanks for your help.

 

[plasticseng]

I believe I would do a compression test next. Primary timing chain broken, maybe?