First of all HI to All
I have a 2005 f250 egr delete AFE cold air intake 6 in exhaust, new Hpop, with 199000 miles I rebuilt the engine at 149k oversized pistons .50 has ran great for 2 years after the rebuild then was throwing the wrench light oil cooler so I replaced the oil cooler screen was intact put every ting back together and now rough idle greyish smoke out the pipe, so i scanned with A/E shows 4 and 6 contribution, so ordered 2 injectors from dcp and still the same did cyl cont test cyl 4 diabled inj 4 and 6 make no diference and those are the 2 i replaced scanned ficm 13.5v in and 48.5 out, and throws a code PO272 any ideas would be appreciated

 

Hi there and welcome
Couple things came to mind, first, since you just replace them injectors, then you should check the injector harness going to the ficm. If you can't see anything then Do an ohm test on each of the 4 wire going the ficm harness. There shouldn't be any resistance or open.

Other thing, check your icp and IPr duty cycle. If icp is running low and IPr percentage is high, it maybe the IPr or hpop or a leak is going. I saying this cause, if there low oil pressure it may just trigger one injector for it may be more sensitive then the others. Some forums have express that with regards this symptom and code.

But my money is on the harness though personally, I'd check that first atleast

 

Have you done or can do an injector buzz test with your scan tool. Because you can try this from this quote, it does mentioned what I told you to do but extra with the buzz test, try it. Here's the quote:

"Could be the fuel injector or the wiring connector.

1. Clear the codes and perform the Key On Engine Off (KOEO) and injector buzz tests to verify if the code P0270 returns as a hard fault without running the vehicle.

2. If the code is a hard fault, access the #4 fuel injector (the second one back on the driver's side). Check the resistance between pins 1 and 2, then 3 and 4 on the injector itself. This will check the resistance of each coil in the injector. The resistance will typically be around 1-2 ohms. If either coil shows abnormally high or low, replace the injector.

3. If the injector checks OK with an ohmmeter, try to swap the harness connectors for injectors 2 and 4. Clear the codes and see if the codes follow the injector. If now the code setting is for #2 injector, again replace the faulty #4 injector.

4. If the code shows #4 injector with a different injector plugged in to the wire harness, check the 4 wires from the #4 injector back to the Fuel Injection Control Module (FICM) for high resistance, open circuit, short to ground, or any continuity to each other and repair as needed."

 

Thanks I will try this in the morning when I get back to my shop