My son was driving the truck and he said it hesitated and then started to smoke a little then he smelled a weird smell. he stopped the truck and opened the hood. The smoke came from the front of the engine compartment. I went to get the truck after a couple of hours. I started the truck and it made a very loud noise, similar to rocks rattling, then stalled, about 3 seconds. I tried to start it again and it would not start. It turns over but will not ignite/start. It sounds like it is spinning with little to know compression. How can I tell if it jumped time? If the valves are bent? I want to cover all bases before I replace the engine.
I don’t know whether this has a timing chain or a timing belt, but you could take off the cover and see if there’s (a) a broken belt or (b) evidence of slippage, like some broken teeth.
Then you could borrow/buy a compression tester and check compression in all cylinders. If a valve is bent, you’ll find out quickly. From the “rocks rattling” noise, that’s probably a good bet.
I have taken the cover off and the belt is tight. Is there a timing mark?
Don’t know which engine you have, but this shows the timing marks on the V6: