Thanks to the peoples republic of california enacting a retroactive smog law, I now have to take my 99, 7.3, F-350 in to be tested. Not too long before it was due, it started throwing the code for #3 injector. I was out of time, took it to a shop, they tested and replaced #3. They also told me I had elevated fuel rail ? pressure. I can't read that one with my low end scanner. After I got it back it started throwing the code for #8 almost immediately. I have since replaced #8 injector, put in new under valve cover wiring harnesses, changed the oil, the fuel filter [minimal soiling], and replaced the cam position sensor [grey]. This problem will just not go away! It is now compounded by california's decision to no longer offer extensions only ! day permits, i.e. I need to fix it before I move it. I am hoping you guys in this Ford brain trust could point me in a usefull direction.
Thanks

 

The last link in my signature might help.

 

good link Tugly!

m Moore- i had a similar problem with mine. I replaced the ICP sensor and the IPR. Ran Diesel Kleen (heavily) and the problem has cleared. This was 6 months ago. I had also extensively cleaned the fuel bowl as well. much trash build up in the bottom. i would try the ICP first since it is the cheapest fix vs the IPR. there is also quite a discussion whether the High Pressure Oil reservoir needs to be sucked out. I suck mine out every oil change now. Just in case. supposedly there can be much oil build up in the heads effecting the injector performance etc. The reservoir takes app 1 qt of oil along with 1qt for every head totally 3 qts of course, but we can go into detail about that later lol.

 

The right directions is to your east and get out of cali. Haha. Only kidding on that. I know nothing on this subject, just see people on my bike forums that go through hell living out there with exhaust, and everything else.

 

The fuel bowl was surprisingly clean, but I drained it anyway.
I will start in on the other suggestions.
Thanks

 

I checked the ICP. I believe oil is only supposed to be on one side of it, so I replaced it. There is a marked difference in coming up to speed when revving it and it seems to run smoother. I am still getting the code for #8 misfire though. Onward to the IPR!

 

Are you getting the code for the misfire while running a test, or just during normal, every day driving? A contribution test will often throw a code for #8 due to the firing order and the way the injectors are fed. With a gray CPS, #3 will also sometimes throw a code.

Does the Kalifornia smog test do a contribution test, or simply a snap test and look at opacity?

 

It's actually pretty easy. Heck, my truck passed. The biggest problem is ignorant techs, and I don't mean that perjoratively. The test is mostly visual, for non-CARB approved items like turbos and ICs and tuners, plus the snap test for smoke opacity. No OBD hookup, the gazillion $ smog machines cannot read a 7.3. except that's my tax money . SES light is naturally a fail, but any intake is OK and same with any exhaust with the caveat that if your underhood sticker says you need a cat it needs to be there.

Just so we understand clearly, does the truck still show an SES light? What code reader are you using, and what code is showing?

 

The code is PO308 and it happens at idle and when driving. The scanner is an Innova. The SES light is the reason the smog test wont pass. If the IPR doesn't get it, I am wondering if I should double check my new injector from the dealership.

 

I don't think the IPR is going to get it. The "new" injector from the dealer is likely a rebuilt injector, so it's possible that is your problem. What happens if you switch the #8 injector with the one next to it? Does the code follow the injector or stay in the same hole? Any other symptoms that something's wrong besides the code? What happens if you remove the CEL bulb from the instrument cluster?

 

Part of the test seems to be turning the engine off and then back on again to make sure that bulb works. Kind of silly as there are codes that have nothing to do with emissions that can trip that light.

 

The IPR was clean and smooth functioning. I swapped #8 and #6 injectors and the code stayed at #8. I am going to test the external wiring next. It has also started smoking badly. I suspect some bad looking o rings on the older injector. I did not change them as I was running a diagnostic, but I will now.

 

The injector O rings stopped the smoking. I appear to have good continuity and no shorts to ground from the 42 pin connector to the injectors. Tracking back the harness I found a rodent chewed loop of red wire where the IDM harness braces off. I have the vain hope this might be it.

 

How are they reading fuel pressure ? are PCMs don't monitor Fuel Pressure.

 

There are many codes that are not emissions related, but only emissions related codes will trip the light according to the OBD2 specs. This is why a SES light is an immediate fail.

Sounds like you found the problem in the harness.