MarcR94v6

I'm dropping the car off tomorrow for the 500 mile checkup for the new motor and am getting it dynoed as well so I figured, why not, put a little race gas in there.

I had an estimated 2 gallons of 91 left and filled it up with about 6 gallons of 100 octane, closed the cap, got in car and it wouldn't start. Took about 4 or 5 empty sounding cranks, then I got out of the car and I noticed behind me someone was wating for the pump. So I get back in and try to start it and it starts right up? . On my way home I stopped at the gas station and filled up the rest of the tank with 91....so I should be where I was shooting for in the 94-96 range...I just wanted a little better than 91.

Should I be worried? I'm obviously telling the shop tomorrow but I'd like to hear something now as a piece of mind.

greenmachinedriver

sounds like a fuel pump pressure check valve problem. also i would not recomend dyno tuning with a higher octane rating than you plan on running on a daily basis. the higher octane will allow the use of mor timing whick may cause ping if using a different fuel.

MarcR94v6

thanks for the reply, but I'm not dyno tuning, just getting some #'s.

Pyrodawg

maybe u just didnt let it prime all the way?

MarcR94v6

No theories anyone else? Seems awfully strange that it happened right after that fill up and hasn't been a problem since.

If I hadn't let the fuel pump prime, the worst that would happen is it would start/idle and then die immidiately because I tried to start it too quick. This was like trying to start a carburetted car that hadn't been started in years.