Help with 1990 GMC Vandura

My son has a 1990 GMC 2500 Vandura van that turns over but will not start. Do you have any ideas what he might try in order to get it to start. Thanks

You need to find out if the trouble is with the ignition or the fuel system since they are the most common trouble for this kind of thing. I suggest he try some starting fluid spayed into the intake to see if that helps get things going. If that makes the engine run a short time then you need to check for a fuel delivery problem. If adding the fluid makes no difference then the trouble could be with the ignition system and you need to check the spark to the plugs. If spark is ok then you need to check compression to make sure the valve timing is ok.

I’m the relay person and I know NOTHING about cars. I did pass this info on to him since he has no computer to do this himself. He said that once he finally gets it started it runs fine, but if he turns it off he may not be able to start it again and it doesn’t seem to matter if it is cold or warm.