C15 Acert BXS shuts off-throws no codes HELP!!!!

Thanks Mr. Haney for your input. Based on your response, I described the problem correctly. I will check the speedometer problem, and I'll bet that is it. As for the shut off issue, I'm sure thinking it's the ECM. When the truck dies, all of the lights on the dash light up until you turn the key off. You can reach down while still rolling and start it right back up. We have checked and rechecked every connection that we can think of. We have wiggled every connection at or near the ECM and batteries with the truck idleing and it will not die. I had a 8.1 L Deere in a Terragator that would not set a code after loosing all throttle control. Deere replaced all kinds of parts and never fixed it. I ordered a used ECM and it fixed the problem. Can you sell me a programmed ECM?

 

One more thing, it acts like you have just turned the key off when it dies. There is no sputtering at all, it simply shuts off.

 

Just found out, we have replaced the speed sensor in the back of the transmission, the socket was clean, and the yoke was tight.

 

Is there any way that the speedometer problem could be ECM related?

 

The speed signal goes from the sensor to the ECM , it then goes rom the ECM to the speedometer , possibly there is a break or bad connection in the cab harness from ECM to cab causing both of your problems, my bet is you are loosing power from the cab to the ECM when its shutting down, be interesting to see what you find, keep us posted.
ps when you say the lights on the dash light up, do you mean like when you turn the key on?

 

Yes, I mean all the warning lights, like when you first turn the truck on.

 

Your problem is most likely in the cab somewhere then my friend, check all fuse connections, maybe wiggle fuses and fuse box with it running.

 

Here is a critical bit of information that the driver just gave me. When the speedometer is fluctuating, the motor is surging up and down like it's trying to follow the speedometer. In other words, the speedometer fluctuation is causing the motor to surge.

 

for the surging issue check the left rear of the engine make sure the speedo harness is not zip tied to the fuel return from the back of the cyl head. Sure sounds like you are loosing key power to the ecm.

 

It will if the cruise is set.