Truck Details:
2004 6.0 F250 extended cab.
Mileage: 1,162,000 Kilometres (the dash stopped at 999,999)
Egr is deleted.
Motor has approximately 120,000 miles on it.
The previous owner delivered campers with it. He said that almost everything in had been replaced except the transmission.

I've had an intermittent crank, no start since I've owned the truck. (2.5 years) It's only happened maybe 5 times and the second attempt was always successful....until yesterday morning.
I feel like I've read extensively on many forums and I'm trying my best to solve this issue. I'm using "Forscan" software on my laptop for diagnostics.

It threw a few codes but none I believe related to the no-start. One code for a transfer case issue, one for a turbo under-boost, one for the ac clutch not communicating, one for the exhaust pressure sensor not communicating. I would list the actual code #'s but after the first scan I reset them due to my ignorance.


While cranking I get the following numbers:

FICM LPWR- 11 to 12.5 volts
FICM MPWR- 47.5 to 48.5 volts
ICP v- up to 1.8 volts
ICP pressure- up to 1493 psi
IPR %- 15 to 55%
No FICM sync
No ckp/cmp sync
RPM- 0 to 60 and fluctuating
FUELPW- 0.00 ms

I've checked hertz across the red and orange wire at the centre plug of the pcm while cranking and i believe it tested good at 1.4 hertz.
The batteries are both getting old and I plan on replacing them but the voltage seems adequate.


The following Forscan tests all checked out good.
PCM KOEO
PCM KOEO injector electrical
TCM KOEO
There were a few others but I think they're irrelevant and they checked out good anyway.

I've visually inspected for chaffing but I need to look harder still. There were definitely no codes regarding the cpm, ckp or ficm. Based on what I've read in other posts, the fluctuating rpm reading should point to something I'm not aware of. I'm not a mechanic but I've learned a lot from these forums. I couldn't even do a brake job before I started reading them.

I appreciate any help/suggestions anyone has to offer.
Thanks

 

On Forscan in graph mode, monitor crank and cam sensors pulse. They should be smooth. IIRC rpm gauge gets a signal from the crank sensor CKP.
You will not have FICM SYNC until you have CMP & CKP sync. Because of NO sync and the erratic tach reading while cranking, I'm suspecting it to be a bad crank sensor or chafe harness. Graph it and let's see what the signal looks like first.

 

I don't have crank or cam sensor pulse as an option on Forscan in graph mode. Would it have a different title? The only title with "pulse" in it is Fuel Pulse Width.

 

Look for CKP & CMP

 

Maybe its the mobile version of Forscan that has CKP and CMP as options. I downloaded the latest windows version of Forscan and it still doesn't have CKP/CMP. I checked and checked again.

 

OK. I might be thinking of the IDS/VCMII system.
Inspect the harness to the crank sensor. The sensor is on the passenger side. Try wiggling the plug. If the crank signal is erratic it won't sync. You may have a bad crank sensor.
Is it cranking fast or slow. Make sure batteries are fully charged and make sure ALL heating/ air-conditioning controls are OFF. If the A/C compressor is bad it won't let the engine spin fast enough to start.

 

Where is the crank sensor located? I'm getting conflicting information on forums and I can't visually see it at all. I have the wheel well out. Is it in a different spot for an 04 compared to other years?
It's cranking fast. Batteries were charged last night and this morning and I still have the charger on. All controls in the cab are off.

 

Had the same symptoms except my rpm was consistent. Mine was a loose cam sensor connection. I traced it back to the pcm connection and it didn't read the correct ohms. It was easier to test the sensor where it plugged into the pcm than at the sensor. You can't even touch that thing without taking things apart. Cam sensors rarely go bad, so if there is a sensor problem it's likely the pigtail or connection.

Cam sensor is on drivers side front of engine. Crank sensor is one passengers side.

The uneven crank concerns me more than the mob start.

 

What are the correct ohm for the cpk and cpm sensors? I'm going to test the cpk's hertz while cranking at the pcm connector and compare the reading with the Forscan fluctuating reading. This, I think should point in the direction of either upstream or downstream from the connector electrically.
Can anyone tell me how I can get a visual on the cpk sensor at the pigtail?

 

I've got that info in a book at home. Im on vacation for most of the week, but will try and post that when I get home. Hopefully someone will come in before then with a diagram showing which pcm conector and pins those are.

My cam sensor was an open circuit when I tested because the connector was loose and not making contact with the sensor. Never messed with the crank sensor since I checked the cam sensor first and found the problem.

 

Crank sensor is the signal the pcm gets before it goes to the tach. I'm suspecting crank sensor or connection. Also check the PCM plug connection. Inspect the harness.
The sensor may even have come loose and vibrated out partially. It's located passenger side below A/C compressor.

 

I ohm'd the sensor from the pcm connector. I was getting a 40 ohm (or was it 40 kilo-ohm?) reading that was dropping out to 0 often. When it would drop to 0 it didn't correlate with any wire twisting or movement. I proceeded to remove the sensor. When I finally got it out, it was covered in oil. Wiped it off, ohm'd it, got just under 400 ohms.
I started thinking that maybe I had 400 the whole time but no, I remember seeing the decimal. It was definitely 40.00 on the volt meter the first time I ohm'd it. I then checked resistance of the wire path from the pcm connector to the ckp connector and back again. It read about 0.8 ohms. I again wiggled the wire path while watching the meter. The resistance didn't change. The circuit seems good.
I then tested the sensor by putting the meter's leads across the sensors 2 prongs in AC volts and waved a metallic object in front of the sensor. It's creating a small 0.03 or so voltage. So it seems to check out good.
I'm not sure where to look next. I'm going to cover the sensor in oil and try the previous test again tomorrow.
At this point, I'm thinking that maybe the gear in side that the sensor reads is damaged but wouldn't the truck have shut down on me if it broke while driving? This issue started by "no start" not while driving.

 

Thanks for the diagram 87. The sensor seemed to be in there pretty good. It's bolted in place. I don't think it could have vibrated out. Even when I got the bolt out, it was hard to pull out. Took me more than a few tries yanking on it in an awkward position. If anyone has access to the spec'd ohm reading on this thing I'd really appreciate it. I'm going to buy a new one and compare the readings from old to new.

 

Getting ready for work but I'll see what I can look up later.
Did you check the harness? Did you check the plug on the PCM?
I'll try to post a pinout of the plug so you can ohm out the harness. I'll be back later.

 

I did check the harness. I tested it's resistance from the connector that plugs in to the pcm. The whole path from the plug, to the cpk and back to the plug is good. Less than 1 ohm of resistance. I just jumped out the cpk connector to test the whole circuit at once. I also wiggled the harness all over while testing and the resistance didn't change so the harness is good.