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2005 Ford F250 6.0, ext cab, 4wd
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Discussion Starter · #1 · (Edited)
Hello everyone, I'm still struggling to run down my random crank no start issue. I thought I had it fixed. Truck was studded, new dummy plugs, standpipes, stc a year ago professionally. 260k. It's ran flawlessly for last year until the last few months. I found my ficm logic power was extremely low, so I sent the ficm to circuit board medics and it's been great for last month, however this evening, it is a crank no start.

(Cranking)
Fuel pressure 52 psi
Ipr 36%
Icp 900
Fmp: 48.5v
Passed injector buzz test
No codes on forscan
OEM filters
Amsoil synthetic diesel oil


Before the ficm replacement, it would run and start perfect, then once every couple weeks a crank no start cold/hot doesn't matter, then fine again. Anything replaced has been OEM except arp studs. I'm very meticulous about maintenance. Hasn't done this in a month. Any help or ideas? I prefer diagnosing rather than throw the "parts cannon" at it. Thanks in advance.
 

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Post cranking data for:
cam/crank sync?
FICM sync?
Injector pulse width?
cranking rpm?
FICM LPower?
 

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2005 Ford F250 6.0, ext cab, 4wd
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38 Posts
Discussion Starter · #3 · (Edited)
Post cranking data for:
cam/crank sync?
FICM sync?
Injector pulse width?
cranking rpm?
FICM LPower?
Cranking rpm: 150
Injector pulse width : 2616
Ficm logic power: 12v
Vbatt: 12v
Ficm to pcm sync: yes
Crank cam sync: yes

Thanks
 

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150 rpm cranking is marginal, I guess it should start.

If it drops below that, it might not start.

Two more PIDs when cranking:
v-reference
ICP sensor volts
 

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2005 Ford F250 6.0, ext cab, 4wd
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Discussion Starter · #5 ·
Since I'm completely stumped and grasping at straws here, a few months ago, I was changing the oil, and my alternator post is missing the rubber plug on top, I accidentally hit it with a ratchet, and it arced off the intercooler pipe. Could that have anything to do with it? The crank no start is intermittent.
 

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Also, what is your fuel tank level?

Think about doing some fuel bubble tests.

I know you said you have 52 psi fuel pressure, but you need to look for bubbles in it when filling an empty secondary fuel filter bowl.

I would also do a cranking bubble test with the secondary fuel filter bowl 3/4 full (looking for combustion gasses getting back into the fuel rails). You can crank with the FICM relay removed or crank by jumpering the starter solenoid wire to the passenger (+) terminal.
 

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Since I'm completely stumped and grasping at straws here, a few months ago, I was changing the oil, and my alternator post is missing the rubber plug on top, I accidentally hit it with a ratchet, and it arced off the intercooler pipe. Could that have anything to do with it? The crank no start is intermittent.
I suppose you could have damaged the FICM or the PCM.
 

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2005 Ford F250 6.0, ext cab, 4wd
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Discussion Starter · #8 ·
I suppose you could have damaged the FICM or the PCM.
The ficm was damaged, the ficm logic was extremely low during crank no start.

Guess I'll have to wait til next time, it started now. I appreciate the help. When it does it again, I'll post ICPv, also.
 

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Discussion Starter · #9 ·
Sitting here with idling, my batts are at 13.1, and ficm logic is 12.5
Not sure if that makes a difference. The ficm from circuit board medics has only been in it 3 weeks
 

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So, ...if you have Injector Pulse Width , then "electrically" the system is working as intended -- and will deliver fuel for combustion

Now the question becomes, is there sufficient fuel pressure at the injectors, and are the spool valves opening to allow the injectors to fire?

You say "passed buzz test" -- did you hear each injector make the sound?

52 psi fuel pressure, you have a gauge installed? -- that is "in spec" but lower than desired, which is 65
 
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Discussion Starter · #11 ·
So, ...if you have Injector Pulse Width , then "electrically" the system is working as intended -- and will deliver fuel for combustion

Now the question becomes, is there sufficient fuel pressure at the injectors, and are the spool valves opening to allow the injectors to fire?

You say "passed buzz test" -- did you hear each injector make the sound?

52 psi fuel pressure, you have a gauge installed? -- that is "in spec" but lower than desired, which is 65
Yes I heard all 8 injectors during the buzz test. 1 click for each of the 8 Injectors.

I have a digital gauge ran into the cab from the fuel bowl. It has a needle and digital numbers. Both are exactly the same. Lately, I've seen it dip down to 47 under acceleration, but usually hangs around 49-54. Fuel filters are motorcraft, installed 5500 Miles ago.
 

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When the engine "acts up", look at the Fuel Pulse Width to be sure it is there -- if so, the rest of the system is working, kind of the last thing in the order of operations to fire the engine -- in this case at least the FICM "thinks" it is sending the injector fire signal -- doing the buzz test would than prove if indeed the FICM will send the signal or not

Random issues are the most frustrating, since they always seem to happen just when you need the truck the most
 
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Just be aware that the FICM can perform the buzz test without the logic board being functional enough to start the engine. It is stated in the FICM Guide.

Edit for clarity - the FICM guide states that the injectors will be "buzzed" at "key on" even without proper logic power.

I can't say for sure if it will interfere with running the actual buzz test w/ a scan tool like ForScan, but I assume it might not.
 

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Discussion Starter · #14 ·
When the engine "acts up", look at the Fuel Pulse Width to be sure it is there -- if so, the rest of the system is working, kind of the last thing in the order of operations to fire the engine -- in this case at least the FICM "thinks" it is sending the injector fire signal -- doing the buzz test would than prove if indeed the FICM will send the signal or not

Random issues are the most frustrating, since they always seem to happen just when you need the truck the most
Yes agreed. This happened 11pm last when I was going to get my son from skating rink. I drive it every day, 5-100 miles, no issues at all for a 3 weeks, then last night, no start. Then it just randomly starts after 30 minutes of diagnosing this morning and starts within a second.
 

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Yes
 

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I like CBM, but that doesn't mean that they are perfect. I would contact them. Maybe they would be kind enough to work out a trade. Intermittent issues are not rare in FICMs.
 

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Also, common to cause intermittent issues are IPR solenoid problems (and EBP sensors).

To test the EBP sensor, just run with it disconnected. Intermittent IPR issues are a bear to diagnose.
 

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Discussion Starter · #19 ·
What would the voltage difference need to be to be out of spec? Right now, koer:
Batts 13.1
Ficm lp: 12.5
 

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Theoretically your FICM logic side should function with volts as low as 8, but I really hate to see less than 10 with the FICM LPower or VPower. I don't think you need to worry about the numbers you posted.

ALSO - be aware that the FICM voltage PIDs are HEAVILY filtered and displayed in .5V increments.
 
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