I'm working on a buddies 98 Blazer with gm4.3, it will crank all day but wont start. Looks like the fuel pump is notorious on these things. One test I read about (i think from a members sig here) states a fuel pressure testing valve. Is that the valve on the hardline near the back of the intake near the distributor with a black cap? The test states to crank the engine and press down on the center of the valve to see if there is fuel pressure at all. I got nothing during the testing which leads me to believe it is the pump or related to no fuel, but I wanted to verify that that is the correct way to check for pressure at all...

Is there a port to access the fuel pump for replacement, or does the tank have to be dropped to replace pump?

 

Fuel pressure service port is in the 3/8" steel line next to the distributor. Connect a fuel pressure tester to the port, key ON, engine OFF, fuel pump running: pressure must be 60psi to 66psi and must remain above 50psi for 10 minutes after the pump shuts off. On your 98, in the underhood fuse panel, next to the fuel pump relay, there is a small vacant female terminal. When you apply battery voltage to the terminal, the fuel pump must run.

If the fuel pump needs replacement, the tank needs to be removed from the vehicle and an AC Delco pump installed, don't waste your time or money on an aftermarket pump.

 

Turn the key to the on position without starting it. Listen for the fuel pump to engage. If there is no noise, your pump is out. If it does, try changing the fuel filter. You might get lucky.