the engine light on. can't pass smog whats the deal. whats the bad news cost

Did you have it scanned to see if a diagnostic code is present: that would help a great deal by pointing in the right direction.If you can't get the van to an auto zone for a scan, then it will be necessary to buy a cheap scanner at Amazon.com.However,check the p.c.v. valve by pulling it out and see if it has strong vacuum and check for vacuum leaks generally and also check the emissions control system like the charcoal canister ,the purge valve solinoid ,leak detection pump and removable filter,the vent line to the tank.My dodge ram has a replaceable filter connected to the leak detection system.Check all the hoses for cracks .Normally it is done with a smoke machine which is very expensive.But if you squeeze the hoses at the connection points one can see if they are soft and musshy.The most difficult part to check is where the vent line connects to the tank because it means lowering the tank.