99 Suburban crate motor hard to start.

[Tanker Jocky]

I have a 99 Suburban 5.7 with a new crate motor. Less than 100 miles on it. Since I installed it 2 weeks ago this engine is really hard to get running after sitting more than an hour. The new style spider was installed about 600 miles before the old engine spun a rod bearing.
After installing the new engine I reset the cmp retard with my scanner and currently reads about .5 so it should be within the +-2 deg the specs call for.
The oil pressure is about 45 at idle warm and 58 going down the highway.
The fuel pressure is reading about 57 psi key on and 54 at idle. I installed a new fuel filter during the install.
It's not showing any codes and other than hard to start it runs great!

Before the old engine blew it started immediately whether it sat overnight or I just shut it off so I don't think it's the spider.

Anyone got any ideas?

Thanks
Al

 

[Kemit]

In what way is it hard to start? Long crank time? Chugging and sputtering?

 

[Big D]

I recently had to replace my fuel pump because the highest it would go with key on is 50 PSI, it wasnt enough to start her up. 57 is a lot closer, but ive always read 60-66psi is the target number to start her up.

 

[Tanker Jocky]

The problem i'm having is a long crank time. And when it does finally fire it's kinda a delayed spool up to idle. Not the typical "varoom!" that it should be.

 

[Kemit]

How old is your fuel pump? Does this only happen after the truck has sat a few hours or overnight? If you turn the key to run 2-3 times for about 3 seconds each, before you try to start it, does it start fine then? If so, the check valve in the fuel pump is not holding pressure. You can test it by installing the pressure gauge when it's cold and see where the pressure is after 1, 2, or 3 cycles of the key. If it slowly builds each time, it's the check valve not holding pressure.

 

[Tanker Jocky]

Fuel pump age is unknown but the pressure and leakdown seems to be good But here is somthing new. Got about 250 miles on the new engine so i changed oil today. With the oil fill cap off the engine lopes really bad.
Lower intake gasket? My scanner has been showing a random miss on #5 cylinder.