I have a 1991 firebird that started life with a 3.1. I ended up swapping in a tbi 350 from a totaled out 95 tahoe. It ran perfectly fine as I drove it to work everyday. But now I have upgraded the heads to vortec heads from a 96 tahoe. I replaced the valves, springs, and seals. Upon first attempt to start to time the motor, it just cranked. It's definitely getting fuel as both injectors are spraying. And it's getting spark too. We've checked all the wires they are in the right spot. We've even adjusted the valves out a little bit and recorded how much still no start. Am I missing something?

 

Check the timing to make sure #1 is at TDC or maybe your valve lash too tight keeping the valves slightly open?

 

That's what we thought it's might have been. Either tdc ain't right or valves are right. I'll try some more when the hurricane leaves

 

Might be EXACTLY at TDC; just, the wrong one.

Don't forget, #1 TDC occurs TWICE during one full engine cycle, but only ONE of those is firing. The other is the end of the exh stroke and beginning of the int stroke, and is also #6 firing.

Take out the #1 plug. Bump the motor over until compression starts coming out of the hole. Bump it until it's almost to the timing mark. That's #1 firing.

 

Any time I set timing on a new motor with a used balancer, I verify the TDC mark. Use a piston stop, rotate the motor until the piston hits the stop - mark the balancer. Now repeat in reverse and remark the balancer. Find the center between your marks and you have true TDC.

 

Thanks for all your help. I will try when I get home tomorrow. I'll let you know