First, my apologies if this has been covered before, but I am in a time crunch to go on a deployment (I work for FEMA) and need answers/info fast.

My vehicle info:
2001 Dodge Dakota Quad Cab 4x4 SLT
4.7 Engine with Automatic Trans

The Problem:
Engine shuts off when it reaches normal operating temp when sitting and idling. After it shuts off, the guages don't work (i.e. no fuel, no batt. no temp, etc.). The engine will turn over but does not start. I checked the computer and it is stating that there are no error codes. However, when the vehicle cools off and/or is cold, it starts right up like there's no porblem at all. It has not shut off on me while driving, only when it is sitting and idling so far.

Also, once the truck dies when it is warm, the code reader cannot communicate with any of the sensors (says that they are not available/installed).

What I have done so far:
Checked all the fuses and relays = OK
Checked battery and electrical connections = OK
Checked alternator at idle and road driving = OK
Tested battery = weak but functional (needs replaced soon)

Computer issue? Gauge cluster crapping the bed? Fuel pump possibly or somehing else?

Both the crankshaft and camshat position sensors have been replaced in the last 5 years and the computer was replaced approximately 10 years ago.

Thanks for your input!

 

Cluster gets the information to display from the PCM on the communications bus. For whatever reason, when you truck gets up to temp, the bus is failing..... So, no gauges, and your scanner can't talk to the PCM...... It is *probably*..... one sensor failing, and taking out the whole bus. So, get it warm, wait till it quits, then start unplugging sensors until the engine starts again. Last one you unplug before it restarts is likely the problem. Hopefully......

 

I would start with a battery replacement. You know it's weak, and as a FEMA guy I'd want a reliable battery under the hood anyway. Besides, when you have an unknown problem, fix known problems that could be a cause first. With an unknown electrical problem, fix the known battery problem first.

After that, I would start on this with the MAF plugged into the hose from the air cleaner to the throttle body, as it's job is to tell the computer how much air is coming in. It'll use a table until the engine is warm, once the O2 sensors are hot enough to work the computer will start using sensor data. Plus, I've noticed that this sensor causes engine shutdowns on this board in the past. Not to mention, this sensor is right on top and easy to get to.

 

UPDATE

Ok, after some screwing around, checking sensors, checking the wiring, still no joy. Still, no warm fuzzies that this old girl has given me for the past 20 years.

However, today it is really messing with me and will not start at all. Also, I did not notice this before, but when I turned the ignition on and the gauges didn't work (she's cold this time), I observed the mileage flashing, and the "No buS" warning popped up. I am assuming now this is a solid indication that the gauge cluster is fooked and needs replacing. Thoughts, opinions, ideas?

And to top it off, the political unrest has my deployment on hold. *sigh*

 

Nope. It's not the gauge cluster. The "No Bus" means the cluster isn't getting any info from the PCM of what the gauges should do. Something on your 5 volt circuit is taking down the entire bus. Rear O2 sensors are famous for that. But, since you now have a hard failure, makes it easier to find. Just start unplugging sensor, until the cluster comes back.

 

UPDATE #2

After playing around with pulling senor connectors all afternoon, I was shown a nifty little trick; hold down the trip thingy as you turn on the ignition. It'll test the instrument cluster when "Chec" appears where the mileage normally is. As HeyYou stated, it twasn't the gauge panel. After the test, it spits out three error codes (920,921, and 999) which according to my friend means the PCM isn't communing with the gauge cluster and therefore and forthwith = the PCM/ECM crapped the bed.

After a few more phone calls, I ordered a reman PCM but it won't be here until next Thursday. Oh, the joys of owning just one vehicle. But after 20 years, she never left me sitting until now.

Anyway, next week I'll be back with the final update (hopefully).

 

Those are standard errors when you do the test. The PCM isn't communicating, because it doesn't really have anything to communicate. Replacing the PCM *might* solve the issue, but, don't be too surprised if it doesn't.....

 

I had a similar issue, it turned out to be flexing in the PCM when warm. As I recall the JTEC PCM is filled with a gel potting that ages and gets temperature sensitive. It was a chase and miss for awhile before I got it to not-start one day and had someone to help me diagnose. Figured out if I held the center (white) connector tight, the truck would start and run fine. On the flip side, if it was running, if I gently pressed down on the connector, the truck would die. I ended up fabricating a bracket to hold all the plugs in flat.

Though during my studying of the issue, another cause for dying-when-warm was the two screws in the front of the PCM being too long. Apparently as the motherboard heats and flexes just slightly to short out against the screws and kills it until it cools off. The solution to that is either take the screws out and carefully sand/cut a little off them, or make some spacers so the screws aren't as deep.