2002 Ram 2500 with 5.9 V8 gas.
Ok, so I've replaced darn near everything I can think of. New parts;


PCM - due to other issues
Crank sensor
Cam sensor
Ignition Coil
Distributor Cap
Wires, Plugs
Alternator
Fuel Pump


also cleaned the grounds and replaced some very bad wires.


Still, the darn thing cranks but won't start. It also stopped charging the battery even with the new alternator. However, before I replaced the PCM, it also wasn't getting any fuel.


I'll hopefully have a helper to see if I'm getting any spark but can you guys think of anything else that might be wrong?


I am getting codes P1491 and P0118. I'd take it in to get fixed but geez, the tow bill would be pretty rough.


Any advice would be greatly appreciated

 

Did you test all those things or just throw parts hoping to hit something? Would have been cheaper to get an AAA membership and wait 5 days to have it towed in somewhere that could diagnose it.

Charging is controlled by the PCM, but if you can't get it to run, it's not going to charge.

 

Well I was checking everything trying to track down the issues and all the things I replaced were corroded and junky looking. The fuel pump wasn't working but that ended up being the PCM.


I am getting fuel at the rails.


Before the truck stopped, it was stalling while driving at around 50mph with a load.
Then it stalled constantly one day and I was able to limp it close enough to push it into the garage.

 

I can't offer much advice since I haven't been able to fix my issue yet, either. But, I can suggest what else to check. In my case, the PCM is not commanding the ground side of the ignition coil circuit to open and close as it should, so there is no current through the coil during cranking. Like you, I have also replaced the crank and cam sensors, as well as the PCM, to no avail. I had my truck towed to a shop and the mechanic can't figure it out, either. At this point I'm guessing it's either a bad wire somewhere, or perhaps the engine jumped timing and the PCM isn't seeing the correct cam/crank sensor synchronization. But you would think that would generate a code. The only code present is related to no voltage at the coil (I don't know the number of this code).

I would verify if you're getting voltage at the coil during cranking. You should have constant 12V to ground on one side of the connector - you can check between the connector prong and the frame to verify that. Then you can check between both prongs of the connector to see if the voltage pulsates as the engine is cranked.

I wish you luck. Please let us know if you figure it out. I will do the same. I'm looking at getting my truck towed again to the dealer.

 

Awesome! Thank you for the lead. Just ordered some new testing equipment. I'll definitely check the voltage at the coil.


I'm waiting for the new 140A fuse to get here till I can do more testing. I put a temporary jumper but I'm not sure if that's the right way to go or not.


I just tested the battery tonight and it's good. However, I did find a possibly link to my slow battery drain. The previous owner installed a power inverter under the seat and the wiring job was very amateur... The ground cable was spliced together poorly with tape and corroded. The power cable was just sitting loose at the terminal. It's unhooked now and the cables have been removed. I had some issues this Fall which I'm assuming stemmed from that.


I've also heard of power cables on the harness getting caught or rubbing when the parking brake has been engaged. I looked and sure enough, the main harness is right above the parking brake. What a drag it'll be to check that over. ***On my truck, the mechanic said he was getting a code for a orange and black wire which on my truck is the closest to that parking brake but I've seen where older models were cutting into a Purple/Black wire.


I haven't dug into the harness situation yet... I'm sure that'll feel great on my back.

 

P0118 Engine Coolant Temp Sensor Voltage Too High

Replace this and reset the pcm.

The asd relay supplies positive power to the coil 02's and injectors, May want to check it.

 

Yeah, I meant to suggest that the original poster check the ASD - good call. In my case, the mechanic working on my truck jumpered the ASD and still got no voltage at the coil, so no luck there, but it's definitely something for the OP to check.

 

Ok, so did some extensive testing today and found that I am getting 12v to one side of the Ignition coil (with key turn) but no power from the computer, should be around 5V. The engine is also chugging slowly and squeeking somewhere, will have to wait for the wife to get home to figure that out. I believe the 12V comes from the ASD side .


Does anyone know the effects of a bad timing chain? I was wondering if the PCM would be able to put out that 5V signal if the chain slipped time or broke. Seems like that crank sensor wouldn't be getting any signal thus no input to the PCM which would cause no signal to turn the Ignition Coil on.

 

Where were you testing for the 5 volts? That should be there any time the key is on. Various sensors that want 5 volts are the crank, and cam sensors, and I suspect the coolant temp sensor as well.

 

I was testing the pulse signal at the Ignition coil input. Just took the distributor cap off and it looks like the arm is no longer at #1 plug for some reason.