Idler pulley allowing car to start when cold but not when it's hot?

If there were a problem with the idler pulley or timing belt tensioner the engine would not start at all. Timing would be way off. More than likely there is a problem with the ignition system, or if the engine does not turn over, then the starter would need to be looked at.

It turns over and over and over. I'm not a mechanic but similar to prev. Experience with loss of timing belt. Just bought yesterday and started and dove during test. After I complete deal he mentions when it gets hot it so.etimrs won't start. Sure enough. He described it as vapor lock but he was told possibly something to do with timing. And said belt replaced 20,000 miles ago. It doesn't seem to be a starter. It's cranking fine.

Then you need to start by checking for spark, also look inside the oil fill hole to see if the camshaft is turning.

I am going to the car now. Will update you.

Checking to see if the camshaft rotates is just checking that the timing belt is still good. If you find that there is spark to the spark plugs then try spraying some starting fluid into the throttle body to see if it would fire off. If there is spark, and using the starting fluid and it still does not start, then there is a fuel issue to find. You would start by checking fuel pressure. A idler pulley would have nothing to do with it starting. Unless it is the one on the timing belt.

Started on third crank this morning. Drove it two blocks to mechanic shop. It would not restart after 5 tries. Will know on Tuesday and give update. Seasoned mechanic there was leaning towards sensor (cam I believe) pretty much ruled out timing belt and started. He mentioned sensors, possible fuel issue (pump), Ignition Something? Will let you know. Thanks for your feedback. I'm no mechanic and have no tools so had to take it to shop. Hoping like hell it's under 400.00 parts and labor!!

Ok, sounds good, lucky you made it to the repair shop.

Mechanic ran diagnostic and it showed nothing. Every time he went to start it the car fired up. Only thing he did was tighten the negative battery clamp and clean it. Will investigate tomorrow some more. Small noise in water pump he said. That might want to replace. That's all for today. Will update more tomorrow.

They replaced cam sensor, crankshaft sensor,(although they didn't register as a problem on diagnostics) and a belt idler pulley that was making noise. When to pick it up today and...it wouldn't start. Doing the same thing and sounds the same as when I dropped it off. Out 494.00 (paid) and they still have my car. Also they charge me for sensors total of 150.00 that I priced online for 70.00. I don't know what to do.

Have you figured it out yet? Have same problem in friends kia. New cam shaft sensor, mass air flow sensor. Vacume sensor vacume hoeses. Fuel pump, throttle position sensor. and other sensors. Starts cold runs fine but if shut off will not start again until cold. It floods its self out take out fuel pump fuse startes right up. But then runs out if fuel. Put fuse back in and is flooded right away. Fuel rail holds vacuum on fuel rail return to tank. Any other ideas of the cause of the problem???? Please email chadmalone@hotmail.com subject Kia sportage.