What would make your suburban V8 engine turn over but not start some or the time but then you wait 10 to 15 minutes and it starts?

Answer 1

Do you keep attempting to start it...? My 1999 k2500 with 454 motor was doing this randomly...sometimes when it was hot sometimes when it was cold sometimes not for days...I was told everything including it was a worn key or a bad ignition or fuses etc...I finally think it was the starter landing on a flat spot and the continual attempts to start it finally got it past the flat spot to engage...I replaced the starter and it has not done it all for 2 weeks and counting so far...i think that was the fix...good luck

Adding to that:

If it turns but doesn't start, then starts 10-15 mins later, it's flooded. Fuel needs to be vaporized for it to combust. If it's in liquid form, you'll smell the fuel while it's cranking, but it won't start. It starts 10-15 minutes later because gasoline has a high evaporation content, so by that time, it's no longer flooded.

I used to have the same issue with the 350 in my camaro. It turned out to be a faulty injector on the throttle body. It was pouring fuel instead of spraying it.