2000 F350 CCLB SRW 280,000. I had an issue about 8-9 months ago driving in a heavy storm and thought water might have been the issue. Service engine light came on and truck started running really rough. No power almost like it was in limp mode. It would come and go as I tried to nurse it home. I thought I had it squared away by replacing the icp with a new motorcraft sensor. I did have a little oil
on the connector and in hind sight I’m thinking maybe I should have replaced the pigtail as well. It seemed to be fine after that and around the same time I went on a buying spree from riffraff and did a lot of projects that I had on the back burner. I did have the VC’s off to replace glow plugs and torque injector hold downs and at the time the VC harness looked solid so I don’t think it’s the harnesses. Truck was running great until about two weeks ago. I was towing my dump trailer home (not a ton of load in the trailer) and it started acting up again. Engine sputtering and missing,no power, boost didn’t appear to be building, etc. I nursed it home and it has sat until my schedule let me get some eyes on it. I purchased a OBDlink MX+ so that I could try forscan lite on my iPhone. I will include some pictures. When I started it, it fired up and almost immediately started to stumble with SES light coming on. I tried with the ICP unplugged and not much change. At one point it started and ran fine then when I throttled up briefly and the rpm’s came back down it began to run rough and light came on. I’m planning on changing oil and fuel filter this weekend to make sure it’s not something dumb. The HPOP seems to be at the right level when I took the plug out to check. If oil change and fuel filter have no effect I will probably Replace the icp pigtail. I wouldn’t mind pulling the ipr but have never done it so I would need to look into the tools to take it off. I have combed the forums for people with similar issues but unfortunately a lot of the threads die without a follow up. My CPS was replaced under a recall when I took it to the dealership shortly after purchasing about 9 years ago. I do have a new cps that I purchased from Ford sitting in my glove box just in case so I could try swapping that out to see if it helps at all. Thanks for any help you can provide in tracking this issue down. I did have an error code at one point for the ICP but wasn’t sure if it was old or existing so I deleted it to see if it would
come back on but hasn’t as of yet. The PERDEL numbers seem odd but I need to research that bc honestly I’m not even sure what they mean yet.

 

PERDELs look perfectly normal, #8 always shows worst. Thanks for posting that, helps a lot!

The P1316 is the one to focus on. Some fault in the wiring that prevents the IDM from working properly, or possibly a bad IDM. Does the poor running correspond to rain? Sometimes water gets into the IDM.

Or could be the big harness that goes over the driver side valve cover to the 42 pin connector. Underside can rub on the VC and short out.

Also pull the 9 pin connectors from each valve cove gasket and look for burnt or melted pins. The connector inside the VC has a history of getting loose and causing these issues.

For further info look up 50 cent mod. Or 52 cent mod, newer version of same idea.

 

initially I thought that might have been the cause when it first happened months ago. It was during Hurricane Ida up in the northeast and I was traveling through some high water. After that it did happen from time to time but not necessarily with bad weather. After that ICP replacement it seemed to go
away. Fortunately /Unfortunately I did a bunch of work on the truck along with the ICP including under the VC’s so maybe i Did tighten up the connection and over the last 9 months it started to loosen again? I’m in the process of assembling a tester to make it easier for ohming the 9 pin harness to see if that is the issue and will report back with those numbers.

 

I'm with David on checking the IDM and associated wiring first. Start ohming at the IDM connector and work your way inwards towards the engine if any anomalies are detected. Do this with the connector disconnected from the IDM and backprobe the connector so you don't spread the contacts.

 

That’s a really helpful image. Thanks. The IDM is located above the drivers side front wheel well? Is that where I would find that harness? I did hook up my tester to the 9 pin and here are the results. Passenger side Cyl had some higher numbers. GLow plugs seemed ok. I used a 9 pin harness that I bought and added about 3’ of wire to extend to a terminal block so I could test each connection easier. I started at the valve covers then I am moving to the 42 pin connector. When I disconnected that I noticed it must have been rubbing on the VC and could definitely be part of the problem. On the 42 pin harness can I just replace the section from the idm to the 42 connection or does the entire harness need to be replaced? Or could I just wrap each wire individually and protect it from future chafe?

 

Just some updated information. I pulled the 42 pin connector apart and tested each cylinder there and here are the numbers. I would say they are pretty similar to the readings at the 9 pin valve cover harnesses. So this is leading me to believe that the problem lies more with the chaffed 42pin wiring harness in the earlier picture although the higher ohm readings on the passenger side are concerning? Does a higher resistance mean I’m due for injectors soon? I’m not really sure what a normal number is. I would think they should be pretty close to the drivers side.

 

The chafed 42 pin wires are likely the problem. That's what caused the P1316. And luckily the damage is not terrible. I'd shoot the area clean with contact cleaner, let dry, and slobber some liquid electrical tape on the worn surface. After it dries a few turns with old school electrical tape, and finally a few inches of split heater hose to protect the area from further rubbing, retained with a couple zip ties. It doesn't need to be pretty new wires, just insulated and protected from wear.

The higher resistance on cyl 5 is suspicious but not necessarily an issue. The PERDELs results show the injector operating normally. I'd repair as above and see how she runs. Another PERDELs test just for gits and shiggles.

If you have an extra six pack and simply must be rid of it immediately, address the cyl 5 resistance. First visually inspect the passenger side 9 pin harness for burns or melting. Pop off the valve cover and see if the inside connector is fully connected. Replace the 9 pin connector pigtail and valve cover gasket if flawed. You can also swap solenoids 5 and 3 to see if the problem follows after you button it all up.

 

That chafed wiring is definitely a concern. Separate them to make sure there are no shorts and then insulate them individually. You may have to splice in fresh wire if any of it is severely chafed. Retest after repair to see if there are any other spots in the harness with issues. Shorts are the quickest way to kill an IDM so do not be surprised if you still get IDM codes after you repair all the wiring.

 

Just a follow up, I wrapped each of the chaffed wires and put another layer of loom over the oem loom and protected it real well. So far so good so that seems to have been the issue. As far as the resistance on the passenger side injectors, does that mean I’m heading toward new injectors? Or is it more likely that it’s a wiring harness issue at the 9pin or potentially under the valve cover?

 

Only way to tell for sure is to work your way in towards the injectors from where your first measured unusual readings. You maybhave to measure all the way to the injector solenoids.

 

High resistance on PS only is most likely 9 pin connector imo. Pull it off and inspect.

If that looks good and the truck is running well, I'd leave it alone.