Okay, this morning was the morning I was supposed to get the blazer of the trailer. Some 5 year old gas is in that tank, so before I ran it, I put some stabilizer in the tank. It ran fine the past few days while I was trying to run the old crap out. This morning when I went to start it up, it was very hard to start, but ran like crap for a few seconds. Now it fires several times but won't start. Occasionally there is a backfire. Cleaned the throttle body and still won't start. I also put about. 2 gallons if fresh gas in. Really annoying. I've always worked on carbed cars so I don't know enough about EFI. Fuel pump runs just fine. Help please!

 

 

Does the gas stabilizer you used also absorb water? Could there still be water in the tank/lines?

Could the stabilizer have loosened up any gunk in the tank which then clogged the filter?

 

All the stabilizer does is absorb water and balance the octane in the old gas. I don't know where the fuel rail is to test pressure.

 

I once had a '92 Vortec and I'm pretty sure I checked the pressure on mine at the supply fuel line where it came up over the rear end of the engine block and before it entered the lower intake manifold.

Freeze the frame of this video at 4:24 and you can see the fitting that I'm recalling.

 

Schrader valve for checking fuel pressure.

 

Thanks!

 

Okay, I have some fuel pressure I use the screwdriver to pump down a little Schrader valve and I got to spread of gas out if I hold the valve down and turn on the key yes brings out as well although there's not that much. I don't have a fuel pressure gauge so I don't exactly know how to test how much pressure there is. It's just a little Spurt of gas not much

 

I don't have a manual that covers 1993 but my Chilton 1994-2004 manual says that for the Central Multiport Fuel Injection System (CMFI) with the key On and the engine NOT running, the pressure should be 58-64 psi. With the engine running at idle, the pressure should decrease by about 3 to 10 psi.

FYI: According to my manual, the CMFI motors in 94 and 95 were the ones that had the cool intakes with the cool swoopy runners and the plenum cover that said Vortec.

Maybe you can rent one of the fuel injection pressure tools from a local shop? I bought one when I had to diagnose and then replace the fuel injection spider in my 1992.

Also, having sat for so long, were you going to change out the fuel filter anyway? If you were, perhaps you should do it now just in the off chance it is the culprit?

 

Any idea where it is? I will change the filter if I could find it