I have a 2000 ram 1500 5.9 gas.

After being warmed up it dies without warning while driving.

NO spitting, sputtering, surging or popping. No change in instrument cluster EXCEPT within 3 sec the speedo then also quits at highway speeds. The tachometer still reads some rpm's (truck still in drive). The code NO BUS used to show up in the odometer, but that has stopped showing up.

Sometimes it will start right back up after turning ignition off, even while still rolling down the highway.

Other times it happens while going slow enough you must pull over. It will either start right back up OR take up to 15 min to restart.

When it does restart immediately it starts normally. If I have been cranking it for a while trying to get it to start it seems to start sluggish for the first 1 or 2 seconds then runs normal, never any spitting, sputtering or popping.

Already took it to the dealership, their diagnostics said replace coil. I replaced the coil with no change. They also said there were NO codes at all in the system.

 

Failing PCM probably...... The no bus is kind of an indicator.

Need to find out what's missing when it won't start. Fuel, or spark, or both..... May be as simple as a cam position sensor..... or not.

Welcome to DF!

 

Just the spark is missing. Fuel is fine.

 

That would imply crank sensor.

 

The speedo then dieing just after the engine died has me question that. The speedometer does work when the engine isn't running IF this other problem isn't currently happening.

 

Not sure if the VSS is on a circuit controlled by the ASD relay, but, if the PCM doesn't see the engine turning, it will disengage it, and a bunch of 12 volt stuff stops getting power. (coil, injectors, for sure.....) I think the VSS is 5 volts from the PCM though.... Might look at the connectors at the pcm, make sure they are clean, and tight.

Does weather make any difference to the symptoms? Is it worse when its raining??

 

I did check to see if the speedo would work without the engine running, it does.

The only weather related item to change things seems to be the warmer it is the more my truck hates me.

 

Heat related is likely to be crank sensor, or PCM.......

 

UPDATE - after problem worsened I borrowed a PCM out after a 1997 5.2.

The gage cluster didn't operate properly, but the truck ran fine.

With the truck warmed up.
- original PCM - problems.
- borrowed PCM - runs fine.
Keeping both PCM'S in the engine bay the whole time to insure they stayed at operating temp.

Swapped PCM'S back and fourth to confirm results.

When engine bay is cool no problems.

My results tell me to replace my PCM with a new one.

Thanks for all the help.

 

What part of the cluster wasn't workin' right?