This 6.4 is my first diesel since a 7.3 years ago.......wow a lot has changed! I bought this truck w/ 146,364 miles, now it has 148,780. It's all stock. It's having injector #7 ssues. Come to find out previous owner replaced #7 @ 146,031.....TWICE! Ford won't honor his warranty since I own it now. I want to know what is causing #7 to fail over and over? Thanks for any and everything.

 

Is it throwing a certain code or how do you know it is messed up? Most #7 and #8 injectors have issues because of the regeneration process. Basically during this process these two injectors release fuel into the cylinder on the exhaust stroke which untimently can cause major issues with the motor. A DPF delete and a tuner to shut down the exhaust sensors will fix any further damage but unfortunately it won't undo what's already been damaged.

 

The code it throws is P0207 and has both times. I have it at a local diesel shop and yesterday they told me they updated the PCM, it ran fine for a bit then, then warnining lights came on in the dash and the PCM is now toast and needs replaced. A new PCM from Ford is $700! They say the PCM has been the issue all along and not bad injectors. A they jerking me around?

 

Ok heres the deal. Most diesel mechanics dont have a clue what they are talking about simply because these newer electronic diesels confuse them and it takes too much work to figure out. A P0207 is an Injector Circuit/Open on Cylinder 7. The easiest way for a mechanic to fix this is to replace an injector. If that doesnt work they reset your PCM. The problem with this is that 99.999% of the time the PCM is not the problem. The code is a result of one of 4 problems:
#1: Bad injector. This is usually the cause of this code but doesn't rule out the possibility of one of the other causes
#2: Open in the wiring to the injector
#3: Short in the wiring to the injector
#4: Bad PCM
IN THIS ORDER!!!! You know like I do that a new PCM is not cheap that is why we start at the top and work our way down. Even if you do not see a problem in the exterior of the wiring it doesnt mean that its OK. Im guessing some of the signs you are seeing are misfires and a rough running engine as well as poor acceleration. The way we fix this problem at my shop, because it is somewhat common, is as follows:

Using a DVOM check the resistance of the injector. If it isn't within specs, then replace the injector. (YOU HAVE ALREADY DONE THIS AND I DOUBT 3 INJECTORS ARE ALL BAD OUT OF THE BOX)
Check for voltage at the fuel injector connector. It should have 10 volts or more.
Visually check the connector for damage or broken wires.
Visually check the injector for damage.
If you have access to an injector tester, activate the injector and see if it operates. If the injector operates, then you likely have either an open in the wiring, or a blocked injector. If you do not have access to a tester, swap the injector with another one and see if the code changes. If the code changes, then change the injector.
At the PCM, remove the driver wire from the PCM connector and Ground the wire. (Make sure you have the correct wire. If you're not sure, do not attempt) The injector should activate
Replace the injector

The P0207 means that the PCM detected a fault in the injector or the wiring to the injector. It monitors the injector and when the injector is activated, the PCM expects to see the voltage pulled "low" or close to zero. When the injector is switched off, the PCM expects to see a voltage that is close to battery voltage or "high". If it doesn't see the expected voltage the PCM will set this code. The PCM also monitors resitance in the circuit. If the resistance is excessively low or high it will set this code.

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Oh and check your oil to make sure its not over full. During the Regen process we see fuel get down in the cam and over fill the oil. It causes a lack of lubrication for the motor and can cause it to over work and run lean. We have seen this cause the PCM to throw most P02 codes.

 

First off let me say thank you so much for all your great advice. Unfortunately I told the shop to go ahead and replace the PCM. They assured me they did 20 pages of guided testing before coming to the conclusion it was the PCM. Last, and most important question I have. Would you keep this truck and all of its possible problems or trade it off for a 6.8 or 6.2 gas?

I have kept a close eye on the oil and it does not seem to be rising. The diesel shop it's at now says they checked it for dilution and didn't see any.

 

Well as far as trading you Powerstroke for a gas motor it all depends on what your doing with your truck and what you expect to get out of your truck. If your doing light to medium pulling here and there (maybe a couple times a month) unless your a diesel fanatic it is financially less expensive to get a newer gas motor truck. From about 2005 up the diesel motors in all makes of trucks have gotten more expensive and eat a ton of fuel, where the gas motors have become more fuel efficient and stronger. A 2008 F250 with a 6.4 Powerstroke that has no mods can run you around $20k low end as a used truck. With diesel fuel running close to $4 a gallon you are lucky if your stock truck gets 15 mpg around town. The only way to get more miles per gallon is to invest around $2500 into new exhaust and a tuner with DPF delete options (that are becoming harder to find). A newer gas motor will get you the same fuel milage stock and unleaded gas is running around 50-70 cents cheaper per gallon.

Back in the 90's and early 2000's the mind set was that going to a gas motor you lost power and sacrificed the longevity of the truck because gas motors did not last as long as diesels. Now days with all the EPA regulations it it starting to flip or become about even. All in all you are going to loose power going to a gas motor but the flip side is that you will save money in fuel parts (when they break) and on the price of the truck itself. It becomes a question of preference and pride.

 

So far the new PCM has fixed the problem. Next question, I want to delete DPF and EGR, is this a risk I want to take w/ my new $700 PCM? I also want to maintain a stock tune, is the DPF-R from Gearbox a good option? Thoughts on DPF verses CAT/DPF delete?

 

Deleting the DPF will be the best thing you ever do to that truck. If you do decide to delete it then you have to have a tuner with a delete program. The best ones on the market right now are H&S and Spartan. any tuner with a delete program is going to run you close to $1200 or more. The EGR cooler on the 6.4 isn't a bad one but yes it can cause issues if it ever goes bad. Personally Ive left mine on just because it hasnt had any problems. Also deleting these things wont cause any issues with the new PCM as long as you have the tuner with the delete program. When it comes to the DPF/CAT delete if you can afford to replace it all then do it. If a diesel cant breathe then it cant make power to move which turns into all sorts of problems and a loss of life expectancy in the motor.

 

Update....the PCM did not fix the problem the rough idle/engine miss came back 1000 miles later. I towed it back to the diesel repair shop and they said it was coding open circuit cylinder 7 again so they replaced the injector free of charge. I drove 100 miles and it started missing again! It's being towed back to the shop for the 3rd time. I'm not sure what they're going to do now but I would love to offer them some advice if anyone has had this problem and knows the fix. Thanks

 

I would say run a buzz test. This will tell you if you have an injector problem or not. Sometimes the buzz test will tell you an injector isnt firing correctly but dont take that as the injector is bad and replace it. Ive seen bad harnessess, frayed wires, connector ends not fully seated, and more. Make sure the buzz test is done and if the injector is dull sounding and not responding quick and loud then move on to the wiring. Watch this video. Its on a 7.3 Powerstroke but it does appy to the 6.4