I'm expecting to get AutoEnginuity later today and will find out what the IDM codes are (P1316 indicates IDM codes are stored). The issue is intermittent, but happens routinely when truck warms up (though it may happen while idling cold shortly after start-up too). There are more details starting at my first post in this thread https://www.ford-trucks.com/forums/8...l#post14534103.

FWIW (as issue is intermittent, not sure if these readings mean much), UVCH plugs outside valve covers both read 2.8-2.9 resistance on each of the four smaller injector pins to center pin and 0.8 on each of the four larger glow plug pins to battery negative. Valve cover gaskets (which include plugs), under valve cover harnesses, glow plugs, and injectors are all new. The plugs on the outside of the valve cover are filled with dielectric grease and pins look good. The one strange thing is driver's side plug at valve cover would not unplug without prying on it a bit with a screw driver--a little snap on each side and it let go. Seems the tab to release wasn't quite releasing it, though I'm 99% sure I had it pressed all the way. After plugging it back in, it comes out easy with the clip depressed, like passenger side.

I'll post back when I learn more.

 

You can measure from the 42-pin connector - it includes more weak links in the reading. There is a UVCH link in my signature.

 

Thanks Tugly. I'll check that after the downpour.

AutoEnginuity brought up one IDM code with KOEO test: P0276 Cylinder 6 Injector Circuit low:
AutoEnginuity KOEO Test Results

It don't know if that cleared the P1316, or if I cleared it last time I checked it with the SCT Flash code reader, as it wasn't present in the complete list of DTCs retrieved this round:
AutoEnginuity Complete DTC List

None of the above DTCs look related, do they? Though they might give me some insight on two other problems--no shift on the fly 4x4 and intermittent backup sensor malfunction. The fuel gauge one is funny; I've never noticed any issues with fuel gauge.

Cylinder 6 indicated by P0276 is on the driver's side. Is this lone code likely to be the cause of the intermittent bad misfire with severe loss of power (as in, can barely crawl up a hill at a few miles per hour), low EGT on driver's side (other side unknown), and black smoke with any throttle?

Does P0276 point to any specific next troubleshooting steps? Likely IDM issue? Or wiring?

I'm wondering if I should do an AutoEnginuity datalog while running to catch the intermittent (but common) misfire. Which PIDs? ICP, IPR, and ?

 

The P0276 indicates the IDM detected that the #6 injector low side circuit is shorted to ground. Check that the underside of the wiring harness going to the 42 pin connector isn't chafed where it crosses over the left valve cover. If that looks good, pull the connector off the left valve cover and check resistance at the second pin from the back to ground, both on the valve cover gasket connector and the wiring harness plug. The resistance should be greater than 10,000 ohms.

 

Hey Guys, new poster here. With yall`s help and reading old post til my brain hurt, I`ve leaned a lot about the 7.3. I`ve been having some of the same issues as stated. Yesterday I took off the 42 pin box to check injectors and found rubbed wires. Boy, its nice to have 8 cyl. again.

 

Yeah, when a wire to an injector shorts, the engine can really start running funky

 

Thanks Tugly, Pikachu, and Lamadman (that's ugly, but I'd be happy if I find that's all that's wrong). 42-pin is next. I did the check at UVCH plugs and found cylinder 6 injector wire behaves a little different than the rest. It will end up showing OL (> 60 megaohms on Fluke 28II), but will often flash ~40 megaohms when I first put the test lead on it. This is consistent on this one, while the other ones show OL immediately (except for one on the passenger side that flashed ~25 megaohms once, though I didn't manage to get it again and forgot which one, and cylinder 4 does it occasionally, but not as often). Though this is really high resistance, it might fit with the intermittent part of my issue and the fact it is not so common on start-up as when hot.

I think I read somewhere that when the IDM detects a short it shuts down the whole bank. Is that right? If so, this single code could explain the issues I've had (massive power loss when misfire accompanied by CEL occurs). I'll let you know what I find on the 42-pin.

Just for interest sake, all glow plug connections on plug from wiring harness (not pins in valve gasket plug) gave 1.416 kilo ohms resistance to battery negative and the center pin on each gives a consistent 111.1-111.4 kilo ohms. Valve cover injector pins were all consistent OL (> 60 ohms) on both passenger and driver sides.

For anyone who hasn't done these checks and wants to, they're pretty easy (at least once I got driver's side one disconnected the first time--has been easy to connect/disconnect since then). I did take off the intake tubing from airbox to turbo due to the difficult to disconnect connector, but I don't think I'd need to next time. Checking the pins is doable with a headlamp and well placed multi-meter, but much easier to do the injector to center pin checks (not the ones I'm talking about in this post) with someone else reading the multimeter.

 

When I said to check resistance from the second pin from the back, I left out a word. It's the second small pin from the back. I'm sure you knew that, but just in case someone stumbles across this who doesn't know, I thought I should clarify . . .

 

Yes, I'd read enough old posts (my head hurt too) to know which pins were for injectors and that cylinder 6 was second from the back, but you'd be surprised what a guy doesn't know/think of at times. When I first looked at this I spent some time trying to figure out how to unclip the 42-pin connector and never thought the 10mm head bolt might have something to do with it... My does it come apart easy with that

And it looks like I have a short where the wires from the 42-pin connector rub on the valve cover:


If this was causing my issues, I'm amazed yours ran at all until it got that bad, lamadman. I pulled the wires apart after taking the picture and it looks like only the obvious one in the above picture has worn all the way through the insulation. I haven't checked whether this wire corresponds to cylinder 6, but I'm going to bet on it.

I'm thinking some electrical tape and a look to see if I can keep this from rubbing on the valve cover again should do the trick for now. Is there a preferred/ideal fix for this issue?

 

For others reading, this is the pin in question for cylinder 6 injector:


And an overall picture (I stuck the negative lead into the battery post clamp in a way that made solid contact and was easily able to take measurements from pins to ground wearing a headlamp with meter positioned here):


Where I saw the momentary slightly lower than 60 mega ohm resistance readings was on the female side plug that goes into the above connector (hole immediately left of center):


The cause is almost certainly the short on the outboard side of the 42-pin connector as shown in the picture in my previous post above. Accordingly to Tugly's very helpful UVCH 42-pin IDM diagnostic trouble code chart (https://www.ford-trucks.com/forums/1...-material.html), it looks like that wire does indeed correspond to cylinder 6.

 

So with that taped up and 42-pin connector reconnected, glow plug pins holes on that aqua connector now consistently read 0.3 ohms... I was sure I checked all of them on both sides before at 1.416 kilo ohms. I'm not sure what the deal was here, but threw it in in case my old just for interest numbers were more likely to confuse than help someone. The center pin resistance to battery negative is unchanged from what I posted before.

 

Yea wild the thing had been giving me fits the last couple months. It had been acting up more lately. Im glad I took my time and checked things out slowly without running to the ford place or something. All I did for the harness fix was separate the wires. Wrap each wire with black tape then covered the bundle with new tape. Then I added a piece of steel wool and taped it in for some cushion so it does not happen again.

 

Thanks for that pic; I think I might have to find some steel wool I managed to get mine off the valve cover, but don't think I want to keep it this way long as the little cover around the bolt head on the 42-pin connector will probably cut through insulation with this arrangement:




All put back together (taking out those air intake tubes really did open things up in this area:


The truck appears to run great now, though I haven't taken it for a longer drive yet. Thanks all for your help!

I'll likely be back later on to deal with some of the other DTCs on my list. Now that I have those recorded, there isn't any reason not to clear them all, is there?

 

I would remove the steel wool and replace it with a non conducting material! Have you ever watched what happens when you touch a 9v battery to a piece of steel wool? FIRE

Not only will that act as a conductor if any of your wires chafe again, but should that steel wool get a spark it will burst into fire. It's one of the best survial fire starters around.

Replace it wish something else if you feel the need for padding.

 

Um, yeah. Not only is it flammable, it rusts and it's abrasive!