I have an 1995 Blazer 4.3 V6 that has been hard to start. I can hear the fuel pump running and have changed the filter under the drivers door. If you try to start it, it will turn over. I turn the key off and back on, let the fuel pump run then try to start and repeat as many as 10 times. Once the blazer has started it runs a little rough for a minute , then it runs fine, can drive for hours without a problem. If I don't wait to long between starts, it does fine. I have been out of town for two weeks and I can't get it started, sprayed a little starting fluid in the air intake and it started. Later today tried to start it again and it will not start.
Any suggestions on where to start looking for the problem would be helpful.
FYI, Spider and popets were changed a couple of years ago.

 

Have you checked the fuel pressure?

 

Test the fuel pressure & leak down rate. The CPI engine is notorious for leaking poppet and/or 'nut kit' (internal fuel lines). The fuel pressure needs to be >55psi and it must hold above 50psi for 10 minutes after the pump shuts off. If either of those criteria are not met, you have a fuel system issue.

 

I have not checked the fuel pressure. Where is the best place to check it, at filter, before or after?

 

Fuel pressure test port located on the main fuel supply line at the back of the intake manifold.

 

I'll start there, thanks. I'll check back with the results in a day or two.

 

Checked the fuel pressure, 53/54 PSI, it slowly leaks down but is above 50 PSI for more than 10 minutes. I also replaced several vaccuum lines I think might have been leaking. Purchased a fuel filter, but have not installed it, yet.

 

Doubt the starting issue is fuel filter related, then.
And a vacuum leak can affect that.

Just to be clear.. are you saying if you dump a little gas in the throttle body it always starts quick?
Notice any probs with your cold or warmed up idle rpm?

 

I'm saying that I can spray a little starting fluid in at the air filter and it starts. Once it is started it runs fine.

 

That fuel pressure is boarder line at best.