96 GMC Sierra Won't Start

[KPA]

I was driving my 96 Sierra (2wd, 5.0L) yesterday & it just died.
I am getting fuel pressure to the top of throttle body & if I pour gas in the throttle body it will start,but on it's own nothing.
Any help would be appreciated.

 

[Molson02536]

I was driving my 96 Sierra (2wd, 5.0L) yesterday & it just died.
I am getting fuel pressure to the top of throttle body & if I pour gas in the throttle body it will start,but on it's own nothing.
Any help would be appreciated.

Start with the simple and replace your fuel filter, your Injectors need 62-65 PSI to get the engine started and will drop about 5 PSI when the engine is running. Also note that pouring gas down the intake my cause an internal back fire or fire in the upper intake platinum and can cause your fuel injector poppet nozzle to melt.

This will just cause a addition cost to a $15.00 fuel filter to around $500.00 if the injector nozzle are damaged.

 

[KPA]

Replaced the fuel filter - still nothing.

 

[Molson02536]

Replaced the fuel filter - still nothing.

Check your fuel pressure readings at the shredder valve, as mentioned you need 62-65 PSI. Your fuel pump may have go to the end of it's life and will need to be replaced, but before you do that. Inspect your ground wire to your fuel sending unit, a bad ground will cause your fuel pump to be weak causing a low fuel pressure issue. Post me back with your readings and if there good, we can go on to checking if your crank shaft sensor is bad.

If you can rent a scanner at Auto Zone to read for any DTC codes, that would help and if there is no codes. It's your fuel pump, a bad fuel pump sending unit will have no codes.

 

[KPA]

where's the shredder valve at?

 

[KPA]

Located the schrader valve & I get a whopping 12 PSI when I try to start it.
Hooked up a scanner & it says - fuel system mon ok.

Inspect your ground wire to your fuel sending unit, a bad ground will cause your fuel pump to be weak causing a low fuel pressure issue.

where's the fuel sending unit located at?

 

[Molson02536]

Located the schrader valve & I get a whopping 12 PSI when I try to start it.
Hooked up a scanner & it says - fuel system mon ok.

12 PSI , you need a new fuel sending unit, but first check to make sure your ground wire has not corroded off. As mentioned and bad ground would cause yu to have a week fuel pressure also, not sure where on the frame it's grounded to but just follow the harness and trace the ground lead wire to the frame and it will be separate from the rest of the harness.

http://www.compnine.com/index.php?u...delid=6557&capuid=1&majorgroup=02&grouptype=B

 

[KPA]

where's the fuel sending unit located at, hopefully not in the tank with the pump.

 

[Molson02536]

where's the fuel sending unit located at?

In the gas tank, it's your fuel pump which is the whole unit now. Used to be that the pump can also be replaced separately, but not in the 96 and newer. You can mode your sending unit to just replace the pump, but that means extra work but can be done.

Here is a link to where your sending unit is and it's easier to replace it by removing the bed of the Sierra then dropping the gas tank to get to it. Just make sure you replace the wire harness to the sending unit from the frame to the unit. The harness is know to fail after it's been moved around and can cause issues again such as the one your experiencing.

http://www.compnine.com/index.php?u...delid=6557&capuid=1&majorgroup=03&grouptype=B

http://www.compnine.com/index.php?u...delid=6557&capuid=1&majorgroup=03&grouptype=B

http://www.compnine.com/index.php?u...delid=6557&capuid=1&majorgroup=03&grouptype=B

http://gmcowners.com/gmc-forum/showthread.php?t=14591

 

[KPA]

Just make sure you replace the wire harness to the sending unit from the frame to the unit. The harness is know to fail after it's been moved around and can cause issues again such as the one your experiencing.

I unfortunately know about that harness as I've accessed the tank before to replace it when it burned up. While I was at it I also replaced the fuel pump.
If I can't find anything wrong with the ground looks like I'll be doing it again except this time it'll be the entire assembly.

 

[KPA]

Installed new fuel pump this evening & things are working great!
For those interested the fuel pump ground is located directly behind the fuel door on top of the frame.

Many thanks there Molson02536

 

[bill96]

i have a 96 sierra 5.0 wont crank unless you ground the purple or yellow ignition wires any ideas?