My last post I stated I had a miss when the engine was cold. That has turned into a knock, When I start up the truck it runs rough and if I just barely touch the gas it knocks LOUDLY. I have good oil pressure, clean oil. It knocks till the temp reaches 150 degrees. Its so loud that it seems like its going to blow up any second if I try to move the truck. Once it hits the 150 mark all is normal again. What can it be ? Thanks for any input.

2009 6.7 Cummins
smarty jr.
deleted
112000 miles

 

I would get it to a diesel shop and have the injectors looked at. Something does not seem right, have you checked your fuel filter, etc? Also, the name of the motor is Cummins, not Cummings... the last part is just a pet peeve of mine.

 

I had a 6.0L Power Stroke that did the same thing. Check to make sure ALL injectors are firing and firing the right amount of fuel into the motor. I ran mine like that, being that it was runnin rough when first started but then ran fine once it was warmed up and it cost me 4 injectors. It's best you get it into a shop ASAP.

 

If I take my truck to a shop/dealer will I have to return it back to factory spec's. Undelete it ? Will they be able to check it out with the smarty installed ?
How can I check to see if the injectors are firing myself ?
thanks for the inputs.

 

Most likely injector, they will hammer very loud when bad. The way I check is perform injector kill test one by one until you locate bad injector. Your out of warranty so it's on your dime. Last one I replaced was $1600 + labor costs. Injector is coded and needs to be programed into the PCM, write down the code before installing new injector.

 

thanks BigIron70

I guess only the dealer can program the injector ?

 

Starscan or WiTech needed to program code into the ECM, and to perform test to isolate injector causing the problem. Usually can test all injectors and scan for codes for one hour labor time.

 

No anyone with a StarScan can do it.

 

Shouldn't I be getting a code with this problem ? I checked my Edge gauge/monitor for codes and nothing shows up.
Thanks for the inputs.

gordy

 

No codes, the ECM can only see shorts and opens. That means that you may have a mechanical hard part falure.

 

It finally throws a code. Started up and knocking as usual, Edge shows code of #3 cly misfire. Take it to have the injectors tested an am told that # 3 is at 86% and #6 at 94%. Tell'em to change both. That didn't help one bit with knock. Still knocking till it warms up. Mechanic is trying to figure it out. Any ideas ?

 

He should have done injector kill first to isolate which cylinder is causing knock. Swap that injector to another cylinder and see if knock moved to that cylinder. If it stayed then possible piston damage #3, did cylinder % come up after new injector install? should be 100% with new injector in that cylinder. If still low possible piston damaged and low compression. Notice any excessive blowby out oil fill? telltale sign piston damaged.

 

Thanks Bigiron.
I'm extremely worried now. The knock stayed after a new injector was in stalled.

What would cause a piston to go bad or crack etc ?

 

J nozzle plugged or injector over fueling that cylinder. Some after market oil filters have been known to cause the piston oil cooling nozzle to plug. Piston then overheats and damages cylinder walls and melts.. Fram filters have been known to cause this problem. Stick with Fleetguard or Mopar filters. Fuel contamination can also cause piston damage, water in fuel system becomes explosive when injected under high pressure and temperatures. Example of piston damaged because of fuel contamination.

Fuel sample on left has water contamination. Pull a fuel sample and check for contamination.

 

Water water everywhere and not a drop to drink ! Water in the fuel has caused my problems. In the end 3 new injectors. Drop the tank and clean it out. CUSS and than CUSS again. Then order a AirdogII and cuss a little more. All this time my friend let me use his 1989 Mazda B2200 5 speed stick shifter and I forgot how much fun it was to powerless out on I-10 with the semi's 10 foot off my butt. The thing that's real nice is I'm not walking and that little truck gets 26-28 miles to gal.
Better filtration will save you some heart aches and $. That's my 2 cents, that's all I have left after this.