So I put on a stock pcm to see if my truck would throw codes and it did. I have had a rough idle for a long time and was starting to narrow it down to injector problems. So the truck threw codes P0278, Cyl. 6 and Cyl.7 injector circuit contribution balance fault. So the 2 things I am wondering is where is #6 & #7 and what might cause these codes. Sounds like something in the wiring. I have already done the ucvh and the pigtails that go with them. Any help would be appreciated.

 

#6 is the third cylinder back on the driver side, and #7 is the very back cylinder on the pass. side.

 

I kinda thought that they would be together. Seems pretty far apart any idea what might be causing the problem. Also I forgot to mention that I was also getting high back pressure readings. Since I have the ebpv gutted on mine I am guessing the exhaust back pressure tube is plugged.

 

The PO278 code is #6. PO281 code is #7. Did you get both of those codes?

 

Mine reads 10 on backpressure.

I have some blowby though.


You might have some o-ring issues.

Fuel in the fuel bowl black?

If your having issues in the back cylinders, you might be getting low oil pressure to them.

 

Yes I did get both codes and it said injector circuit contribution/balance fault. Because it said circuit contribution I was thinking maybe it was electrical, I could be wrong though. My back pressure was running in the 20's just cruising down the road with no chip and no load. I noticed when I did my e fuel that the back pressure tube at the top of the motor had a lot of crap in it, it was fairly clogged, but im not sure where the sensor for that actually is. I dont have a fuel bowl but the truck doesnt seem to be using and excessive amount of oil and the injectors are only about 1.5 years old. Not sure what mileage is on them but I dont drive the truck alot. I did have a pretty good puddle of oil awhile back where my ccv tube comes out but it did have a low spot in the tube so I moved it and havent had the issue since then.