[wkristen]

My 2010 auto i30 stalls on start up if it's been sitting in the same spot for over 8 hours (eg. In the mornings, after work). On the second try it starts up normally. Ideas?

[Phil №❶]

Being petrol, not really sure. Fuel injectors should remain full of juice overnight. Does it happen regularly or just occasionally. I would wipe all the spark plug leads with a clean cloth dipped in detergent water and wrung out. High tension leads can be shorted out by the accumulation of dust, so it's important to ensure that the leads are kept as clean as possible. They must be wiped completely dry after cleaning, of course.

Sorry I don't have any other suggestions to offer.

[Dazzler]

Haven't had this issue with our manual FD petrol yet.. may be an issue with the fuel pressure regulator?

Cold Starting Problem - Hyundai Forums : Hyundai Forum

Or it may have a faulty TPS (throttle position sensor) or a faulty MAF (mass air flow) sensor. Whatever they are...

Take it to the dealer and see if it throws any fault codes.

[Just Rick]

Car is still under warranty.now is the time to test the Toyota dealer you bought it from,to see if they honor their word.being a pressurized fuel system,the reason it could be stalling on first start is there MAY be a small airlock n the system,once you go to start it the second time it would have cleared.

[wkristen]

It's the fuel! It actually turned on first go this morning, but it wasn't very smooth. It was near empty - fuel light turned on (doesn't tell me how many K's left) - so I decided I'd put in regular unleaded (91 octane) instead of the Premium I'd been putting in for quite a while now. As soon as I drove off I felt a difference in the drive. The real test was to see how it would start after my 8 and a half hour shift. Turned it on and BAM! perfect start up! Absolutely ecstatic! Could it be maybe the premium was too rich? The last lot of fuel I put in was 98 octane. Every other time it was 95 octane. Or could it be the fuel was dirty? Hmm... Who knows. All I know is it's running so smooth!

[Dazzler]

  Thanks for the update 

[Phil №❶]

If your fuel was dirty, then the filter would still be dirty and the symptoms would remain, so it could be too high octane rating I suppose.

Hope your problem is solved, BTW, IN PETROL CARS ONLY, a 1/2 cup of metho periodically will ensure that you don't get a residue of water in your petrol tank. Water causes corrosion of the tank and of course, doesn't support combustion.

WARNING   ---   Do Not Put Metho In  A Diesel Engine   ---   WARNING