88 crx si starting issue

I recently put my si motor back in. I didnt know if the motor worked, but i went through it anyway. Its all still stock (new bearings, pistons, head, cam, bored .20 over) but has a bizzare starting problem.

It never starts right away no matter what the outside or motor temp. is. When you key the car it cranks like a champ and acts like it wants to start. The motor fires a few times, then dies. I found out if you give it some throttle when its cranking it acts better. When the car does run it idles like a dream.

I thought at first it was the diaphram on the intake manifold or some other vaccum leak. The battery, dizzy, starter, and alternator are new. Any ideas?

Check fast idle valve