Crank, no start condition
 

01 ram 2500 360 gas, 4wd, nv4500 trans.

driving through an intersection last night and the truck suddenly stalled on me. It cranks strong but won't start. I pushed it to a better spot. I can hear the fuel pump buzzing and I've got pressure at the rail. Ether does nothing. Fuses all look ok, and i swapped the ASD relay with wiper relay and still no joy. Using a spark tester I found i have no spark at the plugs or the coil. I only have a test light with me, no meter. It looks like the coil connector isn't getting power while cranking, but I'm alone now and i can't crank it while holding the light. The only code i have is p0442 which is a small evap code that's been on a while.

my next thought is a bad crankshaft position sensor but I'm open to suggestions. Would a bad crank sensor definitely throw a code? Should there be power at the coil with key on only, but not cranking? I will start chasing wires to look for chaffing too. Thanks.

Crank sensor may or may not throw a code.... but, sure sounds like its bad. You should see power at the coil for about 3 seconds at initial key on, then nothing till the pcm sees the engine turning.

Even with a bad crank sensor the coil should get power at key on? Or only if the sensor is good?

It should get power at key on regardless. If the sensor is bad, you won't see power there again until you cycle the ignition to off.

Replaced the crank sensor, no luck. Same condition. I DO have power at the coil connector for a few seconds at key on. However, I'm still not getting spark out of the coil. I'm thinking of replacing the coil next. Then attempting to get the distributor cap off and have a look at the rotor.

That's what I would do!

Update and fix:

it was the coil. For future readers, test this by placing a test light or meter between the coil connector plug and battery ground. You should see power for a second at key on, and then power when cranking the engine. This confirms the ecm is sending power to the coil. Put a spark plug tester or meter between the coil and the coil wire (that goes to the distributor). If you see no blinky blinky, bad coil.

thanks for the help guys.

Can you return the crank sensor? I would be real tempted to put the mopar unit back in......

I don't know. I doubt it. I'm just going to leave it in there and hang on to the old one.

Side note, a couple vacuum lines near the firewall snapped like 100 year old toothpicks when i was fishing the crank sensor out. A green one and a white one together. Anybody have any idea what they're for?

Green one is the transfer case vent and the white one is the vacuum supply for the 4wd