For context this is a 1996/97 Ram Van 3500.
So I got a van from my place of work, it was acting up so they parked it and just let it sit for a year or so. I get hired and come along to drag it out and begin to work on it. Long story short it's a solid, very few rot holes and none of it structural rot. Been working on diagnosing why it won't start, it cranks but just doesn't want to wake up. So naturally I changed the ignition coil and nothing, so I tested how much power was getting to the coil and I got nothing. Did a bit of research online and most places suggest it's due to a bad PCM. So I plugged in a code tested and it showed no connection whatsoever. So I'm pretty confident it's the PCM, however if anyone has anything else that it might be let me know. I've found PCMs ranging from 150 to 300 dollars. I also am curious to know if I would have to program it or would it be pre programmed? And where should I buy it from? Online or just order it from a shop or something?

TLDR: van cranks but no spark so no start, suspect the PCM but don't know where to buy one or if I need to program it myself or if it's preprogrammed.

 

You will only see power at the coil for a bout three seconds after initial key on, after that, the PCM needs to see the engine turning (via the crank sensor) before it will turn power back on.

Does the fuel pump prime when you turn the ignition on?

 

No, the fuel pump doesn't prime, but from what i've read the PCM controls the fuel pump when the key is switched on. If this information is inaccurate I apologize, this is the first Mopar/Dodge I have ever worked on let alone any vehicle with a PCM/ECU.

 

Yep, PCM trips the ASD relay, and Fuel pump relay for three seconds at initial key on. At least, it's supposed to.... If it isn't, need to find out why. Any stored codes? You can use the key trick to pull 'em. Just cycle the key on, off, on, off, on, then count the flashes of the CEL.

 

If you do go to replace the ECM here is something;

hard to find
96/97 are different computers
no programming required

 

I have a 1996 Dodge b2500, this fall suddenly stopped running and was super reliable up until. Changed fuel pump, new ecm,.. so when I take my tester and in the mail fuse box under the hood, the negative doesn't have continuity to the negative on the battery, or anywhere I can reach on the frame. When I turn the key on the fuel pump doesn't kick on but will if I bypass the relay, but still won't start. Any ideas? Where does that main negative splice? I have a multi meter but nothing else other than hand tools.
thank you

 

I thought it was my crank sensor, but that didn't work. Turned out to be the little 5A fuse in the box under the hood. It controls the ASD. When it is shot the O2, FI, and Coil do not turn on. I changed it and it ran about 2 minutes and blew again. Turned out there was a short in a fuel injector wire causing it to blow. I lucked out because i moved the harness trying to put the engine cover on and saw it arc and the engine died. Taped it up, fixed. Hope this helps.