my friend has an 05 F250 thats been having some issues with no starts and stalling. ive tested his ficm voltage and its excellent and his icp numbers while cranking are strong and fires right away when it chooses.
hes had it to the dealer and they tested with a new ficm found it made no difference. when the dealer had it it wasnt connecting to ckp sensor so the tested and found a bad ground fixed and sent it out.

now the truck will randomly stall out while driving especially at lower rpms on bumps and it gives codes for cam and crank position output sensor open. all i have to test with is a multimeter and an edge insight. the dealer suspects the wiring harness and i think its possibly chafed since the owner recently had some of the top end apart.

we are going to be trying some wiggle testing while the engine is running to see if there is a section of harness that shuts the engine down when moved. other than that im out of idea on how to test.
anyone else have similar problems or thoughts?

 

I think you are on the right track with harness chaffing and I think the codes may be from the engine stalling and not necessarily from those particular sensor wires being chaffed. One spot on my truck that started chaffing was where the main engine harness goes under the air cleaner, pull the air filter and look at the harness right under it, also here is a link to the wire chaffing PDF from the tech folder https://www.ford-trucks.com/ford-man...re_chafing.pdf hope this helps.

 

Are either of those sensors oil soaked?

If it is the harness, one of the users on here a while ago had an issue with the pigtail for one of those connectors (crank / cam) and he did a great write up about how he found the part and installed it.

I could be remembering incorrectly, but I think one of the techs (maybe M-chan) said that that approach can be hit and miss because there is some electrical shielding in the harness insulation at those areas that you need to get right if you do a repair. I think he said that's why Ford will just replace the harness for damage to those pigtails.

If this thread continues and I've gotten it all wrong I'll delete or edit this so as not to confuse in the future, but for now maybe that's a start point for you.

 

i know that the cam and crank sensors are on each side of the block i looked for them but couldnt find them where exactly are they?
chafing is hard to find especially with wire loom covering almost all of the wires!

 

That's the thing if it's chaffing the harness cover will be rubbed through where the short is happening

 

Go to the tech folder and download the 6.0 bible. Theres photos of their locations.

 

Just for reference the wire loom does not allways wear through. Some times the chafe comes from ribbing inside the wire loom itself and there is no visible sign makeing it harder to find.

 

Here's the links to the 6.0L bible showing the locations of the CMP and CKP sensors, Page 10: Component Locations and Page 12: Component Locations

 

unbolt the ficm and check the connectors.
the code you are getting are the result of not the cause of the nostart, my guess anyway

 

You ever come up with anything on this?

 

Not yet it's been hard to get time, I have been busy with projects on my truck and the owner works nightshift. Im gonna try more either later today or tomorrow

 

so we found where the problem is originating! we started the truck and were checking under the hood and went to go check on a scanner in the cab, closed the hood and the truck stumbled and almost died. we slammed the hood and it dies.
so we ran the engine and wiggled every wire we could again. we found that the wires going into the fuse and relay block will kill the engine immediately when disturbed.

 

When you find the exact location perhaps you could take a photo of the problem area. That's good that you found something.

 

If I get the chance i will. im pretty sure he is going to send it to the dealer to be repaired since he doesnt have the tools or knowledge and i am leaving to go back up to site tomorrow.
the problem spot is the upper harness on the fuse block closest to the front of the truck. it appears the fuse block has 4 harnesses entering it 2 on the front and 2 on the back one upper one lower.

 

Update On the truck, took into an automotive electrical shop,the tech inspected removed the fuse box and said everything looked good. Inspected harnesses and connections and still couldnt find anything. Only thing he noticed was a blown fuse that I didn't see.any info or suggestions would be greatly appreciated! Thanks