93 gmc jimmy

[Snowking]

i have a 93 jimmy with a 4.3 vortec that doesnt start sometimes. put the fuel pressure gauge on it and turning the key into the on position it goes up to 60 psi then when the fuel pump stops the fuel pressure drops to about 10 psi there is no pressure with in 1 minute. so is it the pressure regulater or is it a check valve? thanks chad

[Jeremy airjer W]

Most likely the check valve/pump. If this has the aluminum upper intake/plenum than I have also run into the lines inside the plenum leaking.

[deadeye]

Those lines always go bad, but it does sound like the pump check valve to me. Pull the plenum off and if there is a leak you will see it right away when you turn the key to on. Much easier to pull the intake and check that before dropping the tank.

[Snowking]

pulled the plenum off today. fuel pressure regulator was bad.

[Jeremy airjer W]

Fuel pressure is holding steady after you replaced it?

[Snowking]

holding strong. while the plenum was off took the oppertunity to replace all the vacum lines,decarboned the plenum. shes running like never before.

[deadeye]

Nice, when those motors are running right they are great. 290hp on my 4.3.

[Macgyver55]

Nice, when those motors are running right they are great. 290hp on my 4.3.

Wow! what did you do to add the extra 100 HP? Even the 2009 0nes only show 195 HP!

[deadeye]

Headwork, exhaust, cam, and computer upgrade. It stands right up and goes. I had a buddy with a 03 blazer and for fun we lined up one night at a stoplight and let them rip. It was pretty funny he didnt even stay close, I actually saw both of his headlights in the rearview mirror in a half block. The factory de-tunes the heck out of them to make them more reliable and fuel efficient. For whatever reason a 350 in the same year makes 195hp too. kinda sad for a v8.

One of my co-workers has one thats bored out a little bit and with some exrta coaxing it made closer to 400. Its just a small block chev with 2 cylinders lopped off so the sky is the limit as far as power goes.

Sad thing is that as good as that is my car with a 4 banger makes more power than my blazer does. Of course its slightly modified too.