History: 2005 F-250 6.0L with 253k miles, bought in '08 with 40k. Changed turbo at 83k. Changed all 8 injectors, HPOP, EGR delete, SCT Livewire tuner added December 2012 and had to get 4 injectors subsequently changed out from January 2014 to present day.

Fluids: In my diesel, I change oil every 5k, fuel filter's every 10k (Didn't know why to use Motorcraft filters until after research and after I did my last oil change.) Oil always Rotella. Used to use 15-40, switched to 10-30 when cold outside and as of last oil change, T6 5-40 syn. I have NEVER, in all these years drained my water separator (Don't kill me, just didn't know it was necessary! I also wonder if this could be why my damn injectors are failing) but I did locate it today and tried to twist the plug to drain it but it wouldn't budge without having to put on some serious elbow grease... so instead of risking damaging the plug and being stuck at work, I decided I had better wait to have a replacement plug on standby...

Issues: I changed my injectors late 2012 and after they were changed, I would pull up to a stop light and every once in a while I would have a little rough idle until I took off again... didn't start having cold start issues for a couple of months after the injector change. I disregarded it and kept rolling. Fast forward to about November 2013 to present. Cold start's began to really get bad as far as missing and whatnot, even when plugged in at night, but would clear up when at operating temperature. Now, It misses at all temps at all RPM's. FICM varies 46-48.5V, only time it is lower is when it is cold outside and battery is weak... usually 35v pre start. I will say this, in the past, every time I changed my fuel filter, my truck always seemed to run better at least for a very short time but it always returned to not so smooth operation eventually.. Any ideas? Thanks...

 

The batteries must be checked and if questionable replace ASAP. Proper voltage is critical for ficm. If ficm volts are dropping I would get that resolved before going further. Also check fuel pressure if you have original fuel pump.

 

Well, that's the thing. The voltage on the FICM is only 35v in very cold weather without the block heater on with KOEO, battery voltage around 10v or so. Every other time, when it's warmer outside, engine warm, engine running.. it is 46-48.5 so I am thinking I am getting false values in cold weather due to the weaker battery state, as I have read elsewhere. Pump is stock though...

 

I would get batteries checked and probably replaced with new if least bit questionable. ( 10 v is too low) There is a port on front of fuel filter housing where you can test by regulator. You will need correct fitting but easy once you have gauge and fitting. The stock pump is pretty durable, but proper pressure is important. Would be helpful if you could get scanner and check for codes too.

 

Agreed, low batteries will make these trucks run like crap, it is amazing how quick it starts with new ones. This should help clear up the poor running but you should also do the "BLUE SPRING" update for the fuel pressure, it installs on the front of the top fuel filter housing. Ford realized that the stock spring would get weak and allow the fuel pressure to drop below safe limits, the blue fuel pressure spring brings the pressure up to around 60psi, low fuel pressure will allow the plunger to actually strike the inside of the injector and this is never good. The easiest way to fix your pump is to take it off the truck, if you have the right tools for the fuel line disconnect then it will only take about 15 minutes to take it off, while it is off and with the filter out and the side plate off go ahead and give it a good cleaning, it is scary at all the junk that gets left in there even after changing filters regularly

 

Well, I haven't been able to get off work long enough to do much, but I did change the oil filter and it run's a hell of a lot better. A NAPA Gold oil filter was installed so of course, I had to get another cap and filter. I purchased the Racor brand. Its crazy... as small of a difference an oil filter SEEMS to be, ohhhh, how it can affect your performance! I can still feel it missing somewhat but it is not nearly as defined... I plan on changing fuel filter's (Racor) and draining water separator tomorrow, weather permitting...

P.S. Does anyone feel annoyed by the fact that just about every single tech post hardly ever has a solid resolution? The people ask a question, get 4 or more possible answers and never reply once fixed... Nothing can be learned this way... I don't get it.. LOL

 

 

Ok, changed fuel filter's and drained separator... unfortunately, it did not solve my problem. Now, on the way home, I was doing some WOT runs and the ICP would go from 3000 or so to 1700 (very quick, sharp drops) Doing further research indicated that the ICP is not supposed to be erratic but it is supposed to be steady. I took a pic of my meter, truck at idle. I reset the min/max and let it run for about 20 seconds before taking the picture. In that 20 seconds, idle was rough and ICP was in all places in between the min/max shown... Bad ICP sensor?