Truck cranks but doesnt start

[obsguy124]

I kinda feel like a broken record on this one. A Vortec small block (with the original poppet valve injector setup) fuel pressure spec is 58-62 psi. Once they start getting down around the mid 50's, this will vary from truck to truck, there's not enough pressure to open the poppet valves and the truck will not start. If the pressure is marginal you may get it to start by cycling the key enough times for the system to prime and the pressure to just barely crack the "good" mark, it may run OK but stall unexpectedly, etc.

Chasing other scenarios is kind of pointless until the fuel pressure issue is dealt with. If the filter is old, try replacing that first.

Those with the injector upgrade to the MPFI setup find that their pressure runs consistently a little lower than spec, that is fine; those are real injectors with no poppet valve setup and they are far less finicky about fuel pressure.

Richard

I will try to prime the system to see if I can get it to start even just for a little bit but even if the fuel pump IS the problem dont you think the starter fluids would have worked? I sprayed some in and thats when it all backfired and smoke came out of the intake.

 

[someotherguy]

No

 

[SUBURBAN5]

Also did your fuel pump make the startup noise when you turn the key to ON position after it died?

Dont remember sorry

 

[obsguy124]

So changing out the fuel pump would be the way to go it seems, ill see if I can get one ordered thanks for the help guys ill let you know if it works.

 

[SUBURBAN5]

Stick to oem or better fuel pumps btw.

 

[obsguy124]

How this one look? https://www.rockauto.com/en/catalog...kup,5.7l+v8,1303614,fuel+&+air,fuel+pump,6256

 

[SUBURBAN5]

I personally like AC Delco. When I bought my fuel pump it came with everything the sending unit and the pump. Also I believe you might need a special tool because the fuel lines are the type that push in and locked. That have metal tab that lock the fitting. It also has a snap ring on mine

 

[obsguy124]

Gotcha thanks.

 

[SUBURBAN5]

Also yours being a Silverado. You either have to lift the bed or drop the tank. Just an FYI. Mind being a Suburban I just made an access panel.but my tank is at a different location

 

[obsguy124]

Yeah ill most likely end up just lifting the bed, I dont feel like making a big ugly hole in the truck bed haha