So for those who know I just got the 6.0 back with 4 new injectors on the right side. Also was seeing FICM voltages around 44.5V so I installed a new FICM as well. Below are three issues I would appreciate feedback on.

Weather here was in the low 50's in the morning and the 6.0 would run incredibly rough and smoke like crazy but would smooth out after warming up. The next morning I did a cold injector test and got low circuit codes on 1, 4 and 8. Should I be concerned that the new injector is showing low as well?

Also I had been having low voltage issues that I thought I had resolved. When checking my log file after pulling my camper home I had several times, when stopping so the trailer brakes would be coming into play, my voltages would drop. I log every second and I have 170 logs that show below 13v with the lowest at 12.0v. Almost all of the logs are at below 600rpm which makes me believe they are while sitting at stops. Would this be normal with lights on radio on and both blowers running on high and trailer brakes engaged?

Next question is while pulling the camper home my fuel pressure was constantly dropping to high 40's low 50's while accelerating or climbing a hill. I never pushed it to see how low it would go as I would start letting up anytime pressures would enter the 40's. This is running SCT X3 on 65hp Tow Tune with blue spring upgrade. To give you some perspective I have a 32' TT that is probably around 8000lbs and the fuel pressures would drop this low and the transmission would be shifting before 2500 RPM's to keep the pressures up. Climbing Iowa hills I would sometimes crest hills at 45-50mph, dropping from 60mph, just to allow the pressures to raise back into the 50's. Normal or time for a new pump?

Thanks again everyone for taking the time to share your knowledge.

 

I'll start with a question or 2. First, what typeof injectors did you get? Second, same with the FICM.

The low injectors when cold along with the rough running and smoke that clears when warm sounds alot like classic stiction issues. But since you just replaced the FICM I would check that the three connectors are completely seated.

Now for your voltages, first what alternator do you have? If you still have the stock 110amp one I would serious consider upgrade to a minimum of a 140 amp. The way you voltages are reading the alternator just is not able to keep up with demand. This needs to be address, as low voltage is a killer on the 6.0. Also, you talked about the voltage of your batteries after sitting for a hour, but have they been load tested. That can be why you have low cranking voltage.

What I have personally done on my electrical system is follow TooManyToys advice. I got a 140 amp alternator with a overdrive pulley and I added his suggested cabling. I do see mid 12s voltage when first starting but as soon as the glow plugs turn off i am right at 14v even at idle with everything else on. Also my idle is set at 650Rpm, yours at 580 sure seems low.

As for your fuel pressure you need a minimum of 45 psi. Though you might want to by thinking about a fuel pump. Again my experience with my truck and the blue mod, is 55 to 60 psi even while towing my trailer over mountain passes out west. One other thing you my want to check is the pick up in the fuel tank.

 

Injectors were Motorcraft. FICM was from AA Ignition. Stiction on a new injector with 1000 miles on it?

I have not replaced the alternator and assume it is original or at least stock. When it was at the shop they also check the batteries out of the truck and they checked out good.

That was my experience as well up until recently with my fuel pressure. It would never drop until this last trip. On the 110 mile trip up to the campground it only dropped into the 50's a couple times. On the way home it was constantly in the low 50's high 40's underload.

How do you check/ what do you look for with the pick up in the fuel tank?

After injectors I am not sure I can swing a new alt and pump at the moment.

 

1000 miles don't know about that. But the other 4 injectors are old so they can be causing issues. A cold uncompensated power balance test with IDS will answer this question quickly.

The fuel pressure issues could be some bad fuel that is clogging the filters, the easy solution. Or your HFCM is starting to fail. BTW how many miles do you have?

Lastly, given your lower voltages i would recheck your alternator. Ed at FICMrepiar has a good description of how to test your alternator warm. I know it sucks having to do more work after doing a major repair, but a lets say not good alternator can get really expensive real quick. It will kill both your batteries and your FICM.

 

How is this for an alternator? https://www.dbelectrical.com/product...t-180-amp.html

Can you replace just the pump in the HFCM? What brand?

Both filters were replaced about 6,000 miles ago with Motorcraft and the filter in the HFCM was check when I started having the first issues 2 months ago.

207,000

 

I got the Bosch 140amp and overdrive pulley from Amazon.

I would just get a motorcraft pump.

 

And new Motorcraft filters while there.

 

Are you able to check for cylinder contribution and or misfires? Sounds like you need injectors on the drivers side too, if 4 and 8 are giving you codes.

 

Was told there were a couple on driverside that were out of spec but should hopefully last me another year to save up before replacing them. I was not concerned about 4 and 8. I was just concerned that #1 was showing low circuit.

 

Well depending on how bad #8 is, it can be pulling #1 down, that is why you need to do an uncompensated power balance test.

 

It looks like you unfortunately have other issues to fix, which can contribute to to more issues.

 

Sure sounds like low fuel pressure killing your injectors. I'm broke too, but sometimes you just gotta do it because it will cost you a lot more shortly. Also, you should be changing oil and filters every 5k miles when using the truck in heavy duty apps, like towing a trailer. I've had my truck start billowing smoke and missing out twice when just changing the fuel filters instantly cleared the problems, and I do change them around 5k.

 

So to make sure I am understanding correctly, with a key on engine off buzz test and #1 showing low circuit on an injector with 1000miles on it this can be caused by another injector pulling it down?

 

I have been monitoring fuel pressure and this is the 1st time I have experienced issues with low pressure.

I do change my oil and filter ever 5K. I was talking about fuel filters which I replaced every 10k.

 

good. And I stated that wrong, I change fuel filters around 10k as well. Just saying though that I've been surprised how much a bad fuel filter can mess up my truck, even if it's not reached 10k miles. And low fuel pressure is not something to take a chance on. I did, and it cost me thousands of dollars.