2008 F450 6.4 Powerstroke. EGR Delete, DPF Delete. The truck starts easy, and it runs great, no lack of power or any other issues. After start up and letting it idle for a few minutes it will start to miss and start smoking slightly, eventually after a few more minutes it will drop a cylinder and start blowing white smoke, smells like diesel/unburnt fuel. If you turn the engine off and restart it runs fine and will repeat the above issue. If I let it idle slightly and start driving, I do not have any issues with the engine cutting off a cylinder. It will however start smoking pretty good at low RPM's when stopped at a light or a stop sign. No smoking at higher RPM's, and the truck runs great, except for the large amounts of smoke when sitting at idle. I have only a code for cylinder #2, contribution, and if I turn off injector #2 with the scan tool the smoke will stop, and when I turn injector #2 back on smoke again, and I can repeat this procedure with the same results. If I shut fuel down to any other cylinder I still get smoke. I have changed all the injectors in the truck, and I have changed the wiring harnesses for the fuel injectors, and I am still having the same problem with the engine smoking. How do I test the main wiring harness and/or the PCM to see if I am getting a constant signal to the #2 injector causing it to stay open and act like a stuck injector?

 

I'm eyeballing that injector. Not the harness or PCM.

If you can command the injector to sleep thru your scanner and it obviously does, the harness is good as is your PCM. Both are relaying your orders.

To verify, you can swap the injector to another cylinder and either isolate the injector as the cause or rule it out. If the truck still smokes as it is after the swap, command the injector not to fire in the other cylinder (whichever you choose on that bank). If it doesn't smoke............points directly at that injector and nothing else.

If you still have issues, shut down #2 again with the known good injector. Could be in the valve train.

Denny

Denny

 

I have to agree with Denney. You eliminated the injector and wiring harness by shutting off the injector and observing the smoke to clear. Get a noid light and put it on the injector wiring and observe what it is doing when running. It should be blinking, if not and the light is on constant then look at the pcm. IIRC the injector has a constant voltage to it and the pcm grounds the other side.

On a side note a low compression in cylinder number two will do the same thing if you turn off the injector. If compression is low you will get that smoke as the fuel isn't being compressed enough to fire. Low compression won't be as noticeable at higher speeds also. So it might be a good idea to check compression on that cylinder.

 

What was the initial cause and fix to this issue? Having the same problem. I am not convinced it could be valve train issues, my understanding is that the issue would be consistent and occur continuously if it was the valve train? If I am wrong please correct me!