My 2001 Express LT with the Vortec 5.7 won't start. Was driving fine last weekend and suddenly won't start after sitting for 5 days. I check spark plugs, it has spark. The plugs were also wet with fuel. Fuel pressure is good at 60 psi. I tried using starting fluid, but it backfires badly and still doesn't start. The fuel pump was changed about 15k miles ago, and I think the distributor was done about 30k ago (before I got it). It seems to be getting fuel, spark, and compression, all I can think of is the timing is somehow wrong. I have a hard time believing the timing chain skipped, because it ran fine when it was parked. I think I'll try a new distributor. I also considered getting the MFI conversion, but it seems like it's getting fuel so not convinced that will fix it either.

Anyone have any other idea's?

 

bad or weak camshaft position sensor

 

Clean under the dizzy cap. The 8 points get oxidation on them. Rotor too. It may have spark, but maybe not all 8, and it may be weak.
Have you checked for codes?

 

I looked under the cap, it looked pretty clean. Spark looked strong on the 2 cylinders I checked.
No codes.

I could try the camshaft position sensor. Does it control timings?

 

If no codes then its had to assume its a sensor. The crankshaft and camshaft position sensors both give info to the computer for timing.
I would pull all 8 spark plugs. check the gap, (are they iridium)? worn plugs can cause hard cold starting, and misfires.

 

My old 2000 with the 5.7 was a very reliable van but I do remember at one time I had an intermittent problem, (not no start usually) but it would run fine and then all of a sudden it would run terrible and wouldn't go when I gave it gas and later it would run fine again. It actually had my mechanic stumped for a while too but it was a sensor problem, that's what I think you are having also. I think mine was cam position sensor.

 

I replaced the distributor and that fixed it. The Cam position sensor is in the distributor, so not sure if that was it, or if it just needed a new cap and rotor.