Cat power problems

Sounds like what I just went through.
It was a bad wiring harness and bad wires for 2 sensors.

The shop said some of the wires were contacting each other or bare metal and was making this Cat run bad, sometimes ok, miss a lot etc.

We all thought it was bad injectors first, so I changed all 6. Didn’t fix it. Injector cut out didn’t find the problem either. No codes too until I finally forced the truck to throw a light long enough for the mechanic to get the code.

5 volt reference, low voltage.

Then Shop pulled the wiring harness that connects to the ECM and branches out to all the sensors.

Every plug had bare wires right behind it. 2 sensors had bare wires behind the plug.

So as the engine vibrated, the wires likely contact something and then the ECM goes nuts.

 

This problem for my company 6TS Cat was just fixed 3 days ago.

3 Days so far of finally having a purring Kitty.

It was driving me nuts, also because the Cat is straight piped, the sound was ridiculous.

 

Glad you got it fixed!

 

Your issue sounded like mine. I’ve had days the truck ran ok.

Eventually the problem got worse and worse.

My boss was even thinking maybe it was time to pull the head, maybe valve issues.

All because for several weeks we couldn’t get a code to come up even with a loaded trailer, engine missing badly, shaking the truck, mechanic in the passenger seat with his computer hooked up.

Then finally, a code shows up with the mechanic testing the truck after an hour of driving it and it was running fine then went bad from there.

 

Not necessarily even with a dead injector you can still pull full boost at full throttle. But if a oring got nicked or pinched it will cause air in the system. The white or bluish smoke is caused by air in the system. Now yes like bad luck said. If an injector is sticking open that causes air gaps to generate with low fuel pressure. Cut out test may or may not show it. If the boy knows what he is doing while testing you can watch the fuel flow numbers and see which one is off. Have him do a manual cut out if nothing shows on the auto cutout test. If a suction fuel line is cracked it may or may not do it all the time. With the movement of the chassis. Been there done that. Also check primary filter base for cracks as well.

 

Thats another thing also. Old harness may have an itermitted short.

 

My old truck after I had injector cups done, they mistakenly pinched the wiring harnesses in the valve cover. It did the same thing that 1 of the other posters mentioned