Im on pump gas with FIC 660cc injectors, and a custom tune from EFI Logics. I don't have any more specifics on the tune, if needed. Thanks again.

I'd say they need to adjust the tune to better suite the injectors on the cranking tables.

I bet its only when cold. Once the car is warmed up, you can shut/start it with no more problems?

Suprisingly, its the other way around. When it's cold, it starts right up, when it's warm, it hesitates.

I already have an appt to have my tuner do some logs and see what's going on and what he can do. I just wanted to get some other educated opinions, as I am new to this stuff. So, again, thank you.

I know this is an old thread, but I figured I'd post up my solution to the codes I was experiencing in case anyone runs into something similar.

The P0451 code was related to the EVAP solenoid for sure. The hoses must have came loose underneath the manifold.

I ended up popping the P0069 code with the slip light shortly after my last post here back in April. Ended up just being something with the tune I was running. I switched to a tune from Bill @ Delicious Tuning and haven't had a code since.

However, I still had my startup hesitation/fail to start. Everything was pointing to flooding/too rich during start up. Well, I took some logs, sent them to Bill, he sent me an updated tune, and voila, problem solved. He never told me what it was, but I believe he tweaked the scaling for the injectors. I'm assuming the flow data I received with the injectors was incorrect.

Hope this helps someone.

P0451-P0457 are usually evap stuff, +1 on the tighten the gas cap idea

Get just recently got P0451 as well. I am on Vortech.

Just Replaced my Engine with a used, 8k motor after mine blew.

I returned to my perrin Vortech tune (my custom tune supposedly killed my engine).
One thing i noticed is the tuner gave me a 3bar map sensor, when the perrin kit originally came with a 2.5bar. So, i'm running a 3 bar on a tune made for a 2.5 bar - wonder if that has anything to do with it (yes i realize the implications of that in general, a 2.5 is on the way)

I never had this code on my original engine / vortech setup. Nothing else has changed as far as hardware.

I do have Radium dual catch cans, but i had those before, and i've verified the connections to PCV and Crank Vent.

Any ideas?

Anyone else get this issue but not have it deal with the gas cap? I just bought a new one and the CEL is still on... being paranoid im curious to hear stories about what has gone wrong lol

Did you actually read the whole thread? Loads of different conditions lead to the CEL. Take it in. Get it checked.

Thanks @Enalband24
I'm struggling to determine the cause of CEL P0456 and I've noticed on occasion when my car is warm it struggles to turn over. I am thinking my issue is similar to yours in that my engine is flooding/too rich during start up. I am running the base tune from MotoEast on the Sprintex 335; I will contact MotoEast to create a revision tune.

Also, for the longest time I thought the MAPs were configured on the base tune but it ends up none of them are configured. Is this normal or do you have to have the MAPs enabled further then on say the initial base tune?