Engine dies while driving, then speedo quits.

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

Everything points to an intermittent pcm issue i believe

^^^^^ what he said ^^^^^^

I've heard of a bad ground for the PCM
causing the engine to die with no warnings as well .

Have you ruled out bad fuel , intermittent fuel pump ?
Does sound more like a PCM issue .

Welcome to the forum Sir !
Hope you get this figured out ...

Check this out , similar issue on a 2004 .


https://tapatalk.com/shareLink?url=...&share_tid=45797&share_fid=17770&share_type=t

Truck shuts off while driving...help!

Thank you for the suggestions, does anyone know the exact pins in the wiring harness to the PCM that go to ground so that I can test them with a ohm meter?

I don't know the exact pins in the PCM. You could probably find that info in the factory service manual posted in the DIY section. I had a very similar problem with my PCM connections, specifically with the plug closest to the engine. I used some deoxIT spray and dielectric grease to clean the pins and waterproof the plugs. Also used some zip ties to keep the plugs seated nice an tight in the PCM.

Truck has been running pretty solid for some time now...

Good luck.

Downloaded manual, thanks for the heads up on where to find it. Now I can start testing my ground continuity.

New symptom noticed today. When the engine doesn't start back up right away the fuel gage also reads ZERO fuel, along with the speedo not working, but the tachometer, blower fan and radio do work.

If the fuel gage reads normally, the engine will start.

Didn't look at the other gages yet, but it's happening often enough now I'm sure I'll get a chance to check it out.

Sounding more & more like the PCM

Those are the EXACT symptoms that my truck had, when I was experiencing this problem. Next time it does this, pop the hood and press on the plug closest to the engine. If you hear the fuel pump prime, you know that's where your problem is. I think there is a TSB somewhere for loose pins in the PCM connectors...

I did mess/fiddle with the plugs and individual wires going to the PCM with no repeatable change.

But a smack with a rock on the PCM once and slamming closed the hood once killed the engine, again I couldn't repeat that result.


!!! 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.

Thank you very much for all your help.