Cummins ISX issue

Well it's easy enough to clean all connections, recharge and load test then see what happens.

 

Tune is where I would start, sounds like PDQ or a variant there of. Get an Inline reader on there and see what it is doing, or not doing.

 

It cost nothing to charge and load test batteries, why are you so dead set on throwing money at it when you can do a proper diagnostic on it instead of throwing parts at it?

 

Truck ran good until batts went dead. Now truck doesnt run so good. Batterys and connections sound like the perfect place to start. Unless you want to start inventing problems and swapping parts

 

I did not say not to do that. Belching smoke and an unknown tune on a CM-2250 leads me to other areas. Seen one to many CM-2250 and CM-2350 crated up on shop floors going to the scrap yard. Nine times out of ten, issues like this are emissions related. And with all of the very bad and destructive tunes out there, it is an obvious direction to go. If the motor is not showing any codes and doing this, more than likely the tuner has turned off those parameters in the ECM to not throw a code or warning. He could very well have already cooked the motor, the sitting and batteries may have just been a coincidence.

But yes, check the batteries.

 

First

 

I don't see what the batteries would have to do with the truck running rough and belching black smoke. The ECM will shut the truck down if it is getting less than 10 volts of power. The batteries are starting the truck, the truck is running, the fuel system runs off of a mechanical high pressure pump. The batteries would be the least of my concerns.

 

They will, I have seen it too many times.

 

Poor battery's can throw vgt codes as well as supply low voltage to the sensors and ecm. I boosted a truck the other day with a dead alt and drove it in with 7volts. The whole dash dropped out and the truck still ran. Battery connections are the cause of many many problems. I'm not sure how we went from dead battery's to a bad tune?