[mjw930]

Originally Posted by vtirocz

My 3.6L DI engine ('09 Outlook) does not crank long before starting, even in freezing temperatures. I wonder why the system on the LT1 takes so much longer for a seemingly similar setup. Is there a reason the LT1 would take longer to build pressure than the 3.6?

It takes longer to wake up all 455 horses...... Just kidding.

[Mike502]

If you had a key ignition I would imagine you could let it build up pressure then start it. I do this with my 502 and let the fuel pump prime the system then start it. My SS does take a few cranks to start. It doesn't matter if the car sat for a day or week it still doesn't fire on the first crank.

[vtirocz]

Originally Posted by Mike502

If you had a key ignition I would imagine you could let it build up pressure then start it. I do this with my 502 and let the fuel pump prime the system then start it. My SS does take a few cranks to start. It doesn't matter if the car sat for a day or week it still doesn't fire on the first crank.

It's the high pressure pump that needs to build pressure, so engine needs to be turning for that to meet the pressure command.

[Mike502]

So there's no electric fuel pump ?

[Blazin383]

Anyone know if it's the same in the C7 Vettes?

[Glen e]

Its totally the same

[SSport16]

Originally Posted by vtirocz

My 3.6L DI engine ('09 Outlook) does not crank long before starting, even in freezing temperatures. I wonder why the system on the LT1 takes so much longer for a seemingly similar setup. Is there a reason the LT1 would take longer to build pressure than the 3.6?

You have to remember the 3.6 and the 6.2 LT1 are 2 totally different engines. I have that same 3.6 DI engine in my SRX, and yes it starts much quicker, but again the pressure needed is much greater is a large engine like the LT1. My LT1 in my SS takes a few cranks as well, cold or warm, doesn't matter how long it sits.

[6spdhyperblue]

there is an electric fuel pump in the tank but the high pressure fuel pump is mechanically operated by a lobe on the cam.

[6th Gen SS]

Originally Posted by Glen e

#6 on my list- and I tell you why.....

http://www.camaro6.com/forums/showth...=things+normal

You should add

(direct injection)

At end of #6

[JFM-jr]

mine always rolls over a few secs before lighting

[EFI]

Priming is different than pressurizing, I imagine, though I'm not a direct-injection engineer.

Agree. There's a difference between priming (eg. fuel pressure is built from the tank pump to the fuel rails) and pressurizing the cam driven pump. You can't pressurize a mechanical pump without actually moving the cam (and thus the crank) like you do with an electric pump which just requires electrical power.