Car won't start but cranks over?
 

What would cause a Fbody to crank over normally but have no spark of fuel? I have perfect fuel pressure and VATS is turned off. Please list all possibilities.

my car did the same for a while and i just changed the fule filter and it ran fine and i havent had the problem since.iv also heard other reasones one being the crank triger is not reading correctly, also iv heard that the one way valve in the AIR tube can break and on start up there is no back presure or something like that. the first two options i would investigate first

Wow...let's see...here is just what i can think of off the top of my head

Dead/clogged Fuel Pump
Clogged Fuel Filter
Pinched/clogged fuel line
No Gas
Multiple bad fuel injectors
Multiple bad sparks plugs/wires
Multiple bad coil packs
Coil Packs not plugged in
Bad PCM
Bad fuses or relays for ignition/fuel pump/fuel injectors/ etc etc
Any unplugged connectors or pinched wires that control Fuel/Spark


Basically anything that could disable or hinder spark or fuel delivery


Really need more info to better diagnose....did it just shut off on day and never crank back up?....Would it just not start one day? How was it running before the condition developed? so on and so on

Check your fuel pump and ignition relays under the hood. This happened to me in my '02. The car would turn over fine, but the relays were bad, so it wouldn't fire.

Here is some more info on the problem. I didn't give any at first because I wanted to see all possible problems.
Fuel pressure perfect (255 pump that is five years old)
fuel filter replaced three years ago only 10,000 miles on it
full tank of gas
injectors are six month old Fast 36lb
battery is new Optima red top, new altenator
fuel lines are all good
coil packs are stock but none of them are firing
all fuses looked good but I need to check the relays

Here are the symptoms. The car runs great when it starts. In the last three days it started turning over without starting and it would start on like the third or fourth try. Fuel pressure was perfect during each try. Yesterday the car would not start at all without doing a pmc relearn and then it would fire on the first try. Last night at a car show it took over an hour to get it to start so we could come home. We checked last night while we were trying to start it and it had no fuel or spark at all while cranking. It acts like the VATS is messed up and is killing fuel and spark but it is turned off in the PCM so I don't think that is it. We messed with everything last night and finally fired but nothing really seemed to point to one thing or another of what was wrong. When the car finally started it ran perfect, no power loss or misses. When we got home I shut the car off and try to refire it and it did the same thing again so I went to bed pissed off. Let me know what you guys think. I will check anything at this point. Thanks

First thing I would do is check your ignition relay. Most of the relays are the same size, so just swap is out with an accessory relay, and see what happens. It will only take a minute to check.