I have a 4.3 Vortec with a new fuel pump and it is getting spark and no gas line leaks. One day it would not start so I checked the fuel pump with 188,000 I figured check that first. It was not getting the 58-60psi that it should. I changed it and now it will still not start every thing is working power relays and the spark I am lost anyone have any information that could help me out. I also have a new timming chain on so I know its not that.

 

I can't help but ask if you aligned the timing marks when putting the new chain/sprocket on... This can be verified with a compression check to make sure that the cam is in proper time with crank.

Also, did you happen to pull your distributor out at any time? If you did, it could be off by one tooth. This can be verified with a timing light. Take a peice of chalk and mark the 0* BTDC on the crank damper. I think you'll also have to disconnect the computer electronic timing advance wire as well, but I don't know exactly where it is.

Also, you stated that you tested the fuel pressure, but you never stated if you rechecked the pressure with the new pump...

 

Nope the timming chain was in for at least one month before it quit running. I got it running I put new plugs in and put some oil down the holes into the cylinder to crate compression again. From me trying to start it the gas washed out the oil in the cylinder walls. I got a little miss when its cold when it runs at about 60 i feel a little jerk. When the truck warms up it goes away. I have not changed the rotor and cap or wires so im thinking that might be it.

 

And here I was going to recommend the ignition control module.

Sounds like you have it under control.

welcome to the site.

 

The only reason why I said anything about the timing chain is because it was unclear as to when you replaced it. Check all of the basics, fuel, air, & spark.

 

Had problems with a 2002 blazer with not starting.
1- could be the fuel pressure regulator, this will throw off the fuel psi reading and is much cheaper than the pump.
2- check your distributer cap and rotor. Even a bit of corrostion will mess things up.

Hope this helps.