Gobs

I am really stumped and hope someone can give me some ideas.

I have a new GM LS3 430HP in my 55 Chevy and the car runs great. The car starts instantly when cold or sitting overnight. When I drive the car for a while and shut it off for 5 - 30 minutes I have to crank the car over about 10-12 times before it starts.
Any ideas what to look for?
Thanks.
Lorne

SFox

A code reader if you went computer, check the jetting if you went carb'd. I'd check to make sure that the ignition coils are not getting too hot, check to see if you get a spark while it's still warm.

Gobs

I have a modified factory harness and computer but I am not getting a code for the extended cranking.
I never considered the coils getting hot. I will check them out.
Thanks

jrwilliams95z28

shot in the dark but try running a fuel without ethanol, shell 91-93 or similar. worked for me.

Gobs

I never thought of it being the fuel but I will switch to Shell to see what happens.
I even thought of using a hotter spark plug.

Sales2@Texas-speed

iTrader: (5)

I would check the cam sensor as well as make sure the right cam gear is on to match the computer you are trying to use. It is common for cars to be hard to crank when having cam sensor issue but they will run just fine once cranked. Worth checking at least.

Alvin@PCMofNC

Has this ever been tuned? The base tunes that come in the GMPP controllers aren't that bad, but it could just be a fueling issue or something like that giving you a headache. Furthermore what is fuel pressure like when you are trying to start it hot?