08 F550 unable to shut down.

BrunoWilimek · December 23, 2008

Got another odd one here now. Intermittent unable to shut off with key. Key out and it keeps running as if key still in run position. Not able to duplicate. Any ideas? /forums/images/%%GRAEMLIN_URL%%/scratchhead.gif

LARRY BRUDZYNSKI · December 23, 2008

Turbo issues? Oil in the CAC?

Bruce Amacker · December 23, 2008

My experience has shown this to be aftermarket accessory problems 95% of the time. How is this truck set up? What aftermarket wiring/options does it have?

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BrunoWilimek · December 24, 2008

Not a fuel issue. Just not able to shut off vehicle with key. This truck was originally from Washington state and was repossessed by Ford at which time it had a new frame installed under the cab(chassis cab unit). Customer recently had a plow unit installed. But are these red herrings? It did it first thing this morning. Started and immediately tried to shut off, pulled key right out, disconnected ignition switch, still running(normally) as if key was in run postion. Checked wiring diagrams and found something called a run/start relay that powers up many circuits in start and run. Went to inspect BJB relays. Pulled hood release and started to raise hood when it shut off(as if key turned off at that moment). Now unable to duplicate. I will keep you posted. /forums/images/%%GRAEMLIN_URL%%/frown.gif

BrunoWilimek · December 24, 2008

I checked the plow wiring and can't find anything to cause the concern. The start run relay is not the cause as removing it does not affect the engine running. I reflashed the PCM for the 08B06 recall and the SJB for the TSB for plow light operation. Inspecting the wiring diagrams leads me to sevaral possibilites. I only hope it acts up long enough the next time to allow me to trace some circuits. /forums/images/%%GRAEMLIN_URL%%/cheers.gif /forums/images/%%GRAEMLIN_URL%%/drinkingdude.gifHave a few of whatever lights your fire and I will let you know what I find after the weekend.

BrunoWilimek · December 31, 2008

Thanks, Bruce, /forums/images/%%GRAEMLIN_URL%%/thumbup.gif for sending me in the right direction. Well, here's the latest. I think I may have found the cause. The day it actually did it until I opened the hood, I was looking for anything that may have been related to the hood closing and re-located the relay rail for the plow lights. This is a long batch of relays to address the 6.4's use of the SJB to control the headlamps/marker lamps etc., on separate circuits for Boss brand plows. Whoever installed the plow only left enough slack in the wiring harness to fit the relays between the coolant reservoir and the battery. If you are familiar with the 6.4 reservoir, you will know that the top has a dropped down area near the fender to accomodate the hood contour. I also performed the venturi recall and then made the relays fit better to match the contour of the coolant reservoir. I had taken a quick look at the relays and wiring before moving them, but did not look too closely as they were not in my mind related to the concern. After trying unsuccessfully for several days to get the truck to act up, I called hotline to see if they had any ideas. The engineer there did some research and told me to look for anything over .1 volt(even without the concern present)at pin 12 of C1232b at the PCM. I had only .003 volt, so I went back to basics. I re-inspected the wiring to the relays for the plow lights and found a wire had been squeezed between the relays and cut through its insulation, likely by the hood pushing the relays down when closed. There were no witness marks to determine where it had been touching, and the wire was not burnt. However, the battery positive terminal is very close to this area, and even though it has an insulating cover, it is possible the wire may have found its way under the cover and contacted the terminal. I applied liquid electrical tape and then further taped the wires and relays and wire-tied them down away from the battery terminal. I was reluctant to try duplicating the concern by applying 12 volts directly to this particular wire for fear that I would let the smoke out of some electronic component, so am unable to verify if this actually caused the concern. The only link would be the SJB, which is where the ignition switch communicates that it has been turned off, and the lights, which are also controleed by the SJB. The customer has the vehicle back now, so I am hoping that was the cause. /forums/images/%%GRAEMLIN_URL%%/eeeesh.gif

Bruce Amacker · January 1, 2009

The engineer there did some research and told me to look for anything over .1 volt(even without the concern present)at pin 12 of C1232b at the PCM. I had only .003 volt, so I went back to basics.

Pin 12 is not used, I wonder why they were having you check that terminal? It sounds like some kind of internal ground circuit by the voltage levels....

Happy New Year!

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BrunoWilimek · January 2, 2009

Originally Posted By: BrunoWilimek

The engineer there did some research and told me to look for anything over .1 volt(even without the concern present)at pin 12 of C1232b at the PCM. I had only .003 volt, so I went back to basics.

Pin 12 is not used, I wonder why they were having you check that terminal? It sounds like some kind of internal ground circuit by the voltage levels....

Happy New Year!

/forums/images/%%GRAEMLIN_URL%%/cheers.gif

Thanks, Bruce. Happy new year back to you too. Actually that pin is listed as KEYPWR(R/S)on the first page of the 6.4 diesel wiring diagram which is teed into the BJB for the fuel pump diode and pin 1 of the fuel pump relay. I don't think this was related in any way to my concern as it wasn't just running on fuel, it was running as if the key was still in the run position. I would have expected the instrument cluster, DRL etc., to be off if it was simply the fuel pump still running. /forums/images/%%GRAEMLIN_URL%%/shrug.gif

Bruce Amacker · January 3, 2009

Actually that pin is listed as KEYPWR(R/S)on the first page of the 6.4 diesel wiring diagram which is teed into the BJB for the fuel pump diode and pin 1 of the fuel pump relay.

That's connector C1232A, not C1232B.

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