2001 Safari.4.3.....wont start

[Willstox]

I posted once but never showed up? My question is.........do the safari's get vapor locked? My van ran fine, filled the tank up, went 5 miles down the road and it just shut down? It turns over just fine, I checked the fuel pump and it is fine, I turn the motor over and it just about starts but it wont? This happened once before and after trying to start it several times it finally started. What could be the cause of this? 2001 GMC 4.3 Safari.

Note: If I sit in the van, turn the key on several time's....to make sure the fuel pump is sending fuel......it almost starts???

Up date: I took the MAP sensor off and cleaned it, had to put the battery charger on it.....did not start...just makes no since how it will almost start???

UPDATE: I am getting a code...P1683....anyone know what these means and how to correct it?

[happy 2011]

sounds like lack of fuel pressure. Just becaues the pump runs does not mean you have fuel or fuel pressure.

Check the pressure with a gauge

[Willstox]

How hard is it to change the fluid presure switch?

[shadyowl2]

The code p1683 is an error in the ecm. The Eraseable programable read only memory in the computer. It can't read the data in the computer. That is the cause of the no start. The dealer must replace the computer and flash the new one

[Willstox]

Thank you Shadyowl, thats what I was looking for.

Again, Thank you.

[shadyowl2]

There is one other thing you could check too. Make sure your getting spark to the plugs. These 4.3's were also known for the dist cap's cross firing and causing a no start condition. That will tell you definately. This code is a known problem in the newer GM'S for no starts.