Cold start problem

[dzcues]

Hi,

I have an '06 GT with a 4.6 liter Roush forged shortblock, 2300 TVS supercharger, stock Roush tune. It has less than 2K miles on it & runs great. Recently, it developed an odd starting glitch.

It only does this on the first start after sitting overnight. The rest of the day it starts perfectly - no matter how long it sits. This leads me to suspect that temp or condensation have something to do with problem. Does not burn any oil, despite showing a hint of blue at startup. It maintains over 40 PSI fuel pressure overnight. And it runs perfectly when it starts.

Any ideas greatly appreciated.

See 40 second video HERE

 

[JeremyH]

Try starting it in the morning wih some jumper cables on. Could be the battery starting to go.

 

[1fast05]

That starter sounds like its kickin butt to me,battery sounds strong,sounds like an ignition or fuel problem, when you turn the key in the morning before you crank it can you her the fuel pump prime up?

 

[rojizostang]

sounds like it's flooded

 

[Bingo]

I get that sometimes when the weather changes...I dunno if it's the temperature of the reformulation of the gasoline. But normally mine stays running real slow, until I stab the gas...it doesn't cut out like yours.

What gasoline are you using? Perhaps it's a tuning problem?

 

[TonyN]

Looks/sounds to me like fuel or even oil may be loading up in the cylinders over night. Looks like it is burning something at startup too (blueish/grayish - hard to tell). Do you have a catch can or breather setup for the PCV system? Or maybe the injectors may are leaking.

Do you park on angle like that every night?

Does the Roush built engine reuse OEM heads or are they worked up too?

 

[BLKS197]

sounds like it's flooded

+1...what are you doing to get it to start? Are you playing with the accelerator at all, or just trying to crank it?

 

[dzcues]

Thanks for all the replies.

I've tried parking it level & nose high with no difference. Fuel pressure at startup is excellent & it maintains 40 psi overnight. Battery is fine.

In this video, my foot never touched the pedal until it settled down into a slower idle. However, I've tried pumping the gas, cracking the throttle, doing nothing. Nothing helps nor does it affect it adversely. It starts when it feels like it.

Dealer says injectors, etc all good. Roush has no answers.

Summer gas formulation might be an answer. I will run this tank down & try a different brand.

Keep in mind that the car will start perfectly the rest of the day. Hard to believe that a 15 - 20 degree difference will have this effect overnight due to fuel volatility.

 

[TonyN]

Thanks for all the replies.

I've tried parking it level & nose high with no difference. Fuel pressure at startup is excellent & it maintains 40 psi overnight. Battery is fine.

In this video, my foot never touched the pedal until it settled down into a slower idle. However, I've tried pumping the gas, cracking the throttle, doing nothing. Nothing helps nor does it affect it adversely. It starts when it feels like it.

Dealer says injectors, etc all good. Roush has no answers.

Summer gas formulation might be an answer. I will run this tank down & try a different brand.

Keep in mind that the car will start perfectly the rest of the day. Hard to believe that a 15 - 20 degree difference will have this effect overnight due to fuel volatility.

Hmmm, have you tried cleaning your TB? Maybe it is getting stuck closed in the mornings or possibly has a LOT of gunk built up preventing some air from getting through. It's odd that cracking the throttle won't get it to start when it's acting up...

I would def try an alternative gas station as well since it was fine up to this point.

Good luck and let us know how it goes!